Quantification of the iduronate-2-sulfatase activity in prenatal diagnosis of mucopolysaccharidosis type Ⅱ / 中华实用儿科临床杂志

Objective:To evaluate the activity of iduronate-2-sulfatase (IDS) in fetal villi and peripheral blood plasma of pregnant women at high risk of mucopolysaccharidosis type Ⅱ (MPS Ⅱ), and to discuss the application of gene analysis in prenatal diagnosis of MPS Ⅱ.Methods:The enzymatic testing and gene analysis results of 23 pregnant women at high risk of MPS Ⅱ, who underwent prenatal diagnosis in Guangzhou Women and Children′s Medical Center from February 2013 to December 2020, were analyzed retrospectively.The IDS activity in fetal villi (30 cases) and plasma (28 cases) was detected by artificial substrate fluorescence.The IDS activity in fetal villi (28 cases) and plasma (34 cases) of normal pregnant women was taken as control.Meanwhile, the fetal villi of both pregnant women at high risk of MPS Ⅱ and normal pregnant women were also analyzed by gene testing and for fetal sex identification.Data were compared between groups by the independent samples t test. Results:The normal reference values of the IDS activity in fetal villi and plasma of normal pregnant women were(71.2±23.4) nmol/(mg·4 h) and (611.1±114.5) nmol/(mL·4 h), respectively.Among the 30 cases of high-risk fetal villi, the IDS activity in fetal villi of 8 affected male fetuses was (1.7±0.3) nmol/(mg·4 h), which was significantly lower than that of 11 unaffected male fetuses (83.2±6.3) nmol/(mg·4 h) and that of 9 non-carrier female fetuses (80.0±7.5) nmol/(mg·4 h) ( t=10.8, 8.8; all P<0.01). Meanwhile, the IDS activity was measured in the maternal peripheral plasma of 28 pregnant women at high risk of MPS Ⅱ.Among them, the IDS activity in 8 affected male fetuses was(225.4±20.5) nmol/(mL·4 h), which was significantly lower than that in non-affected male fetuses[(451.0±15.1) nmol/(mL·4 h)] and that in non-carrier female fetuses[(467.7±45.3)nmol/(mL·4 h)]. Eight known pathogenic mutations were found in 30 cases at high risk of MPS Ⅱ of fetal villi, and the mutation types were c. 1048A>C, c.212G>A, c.514C>T, c.257C>T, c.425C>T, and c. 998C>T.Of the 8 cases, 6 affected male fetuses had significantly reduced IDS activities, and the other 2 female carriers had normal IDS enzyme activities. Conclusions:The IDS activity in fetal villi and peripheral plasma of pregnant woman is consistent with the gene analysis results.The IDS activity has an important reference value for the prenatal diagnosis of MPS Ⅱ in the first trimester.When no genetic mutations are found in the probands or the pathogenicity of the new mutation remains unclear, the IDS activity in fetal villi can be detected separately for the prenatal diagnosis of MPS Ⅱ.

Newborn screening for Citrin deficiency and molecular characteristics of SLC25A13 variants in Guangzhou population / 中华实用儿科临床杂志

Objective:To investigate the sensitivity of newborn screening for neonatal intrahepatic cholestasis caused by Citrin deficiency (NICCD) based on tandem mass spectrometry and the carrying rate of known pathogenic variants of SLC25A13 in Guangzhou population. Methods:A total of 124 250 neonates born in Guangzhou from January 1, 2015 to December 31, 2018 were performed newborn screening for NICCD by tandem mass spectrometry technology. SLC25 A13 gene mutation analysis was performed to diagnose patients with suspected NICCD.The carrying rate of known pathogenic variants of the SLC25 A13 gene in the whole exon sequencing results of 2 395 healthy children in Guangzhou was retrospective analyzed. Results:Among the 124 250 screened neonates, 31 cases were screened positive for NICCD and one of them was confirmed.Three false negative patients with NICCD were found in this cohort.NICCD screening sensitivity was 25%(1/4 cases). All of the four patients were homozygous for c. 851_854del of SLC25A13.Among 2 395 controls, 60 cases were detected heterozygous variant of SLC25A13, including 8 kinds of reported pathogenic variants.The carrying rate of pathogenic alleles was 1/40 (60/2 395 cases). The estimated prevalence of citrin deficiency was about 1/6 400.The most common variant was c. 851_854del (56.7%, 34/60 cases), and the second was c. 790G>A (23.3%, 14/60 cases). The controversial variant c. 2T>C was detected in 113 children with heterozygous and 2 cases with homozygous and the carrying rate of c. 2T>C was 1/20(117/2 395 cases). Conclusions:The carrying rate of pathogenic variants of SLC25A13 and the estimated prevalence of Citrin deficiency in Guangzhou population are high.The sensitivity of newborn screening for NICCD by tandem mass spectrometry is limited.Even if the negative results for screening of multiple genetic and metabolic diseases by tandem mass spectrometry, it is recommended to recheck blood for newborns or infants with delayed jaundice to avoid missed diagnosis.

Analysis of thyroid stimulating hormone receptor gene mutation in children with hyperthyroidism / 中华内分泌代谢杂志

Objective To explore the characterization of thyroid stimulating hormone receptor(TSHR) gene mutational spectrum in children with hyperthyroidism from Guangzhou. Methods Ninety children were diagnosed with hyperthyroidism from July 2009 to July 2014 in our institute. Their median age at diagnosis was(7.5± 3.4) years, and there were 28 males and 62 females. Mutational analysis were performed by performing polymerase chain reaction (PCR) and DNA direct sequencing of exon 10 of TSHR gene. TSHR gene mutations from 50 unrelated healthy children were served as controls. The correlation between TSHR gene and hyperthyroidism in children was explored. Results A total of 3 mutations were identified in ninety children who were diagnosed with hyperthyroidism, one synonymous mutations(p.V614V), and two missense mutations( p. R707W and p. D727E). Mutation of p. V614V do not change amino acid and do not influence the structure and function of TSHR, no pathogenicity. p.R707W is a SNP associated with human cancers. The frequency of C allele of the D727E in children with hyperthyroidism was 86.7%, while 55.0% in the controls, significant different between the children with hyperthyroidism and the controls( P＜0. 01). In this study, a very high association between the D727E SNP and hyperthyroidism ( OR=18. 86, P＜0. 01) was found. Conclusion Three different mutations of TSHR gene exon 10 were identified in 90 children with hyperthyroidism, (c.1842A＞G,p.V614V、c.2119C＞T,p.R707W、c.2181G＞C,p.D727E), there were association between p.D727E and hyperthyroidism, nor p. V614V and p. R707W. Finally, p. D727E may be correlated with hyperthyroidism in children.

DUOX2 hotspots variants and outcomes of patients with congenital hypothyroidism suspected thyroid dyshormonogenesis / 中华实用儿科临床杂志

Objective To investigate prospectively molecular and clinical characteristics of infants with congenital hypothyroidism (CH) caused by DUOX2 mutations in Guangzhou.Methods A population-based cohort of 83patients with CH were recruited based on newborn screening results among 108 899 newborns who were born in Guangzhou between April 1 and September 30 in 2015.Genetic analysis of DUOX2 hotspots(including 11 exons) by PCR-direct sequencing was performed in 52 patients with suspected thyroid dyshormonogenesis (SDH) according to thyroid ultrasound at diagnosis.All the patients were followed up for 3 years.The data of this cohort study(prevalence of CH,detection rate of DUOX2,clinical features) were compared with those of 96 patients with SDH in 2011-2012.Results (1) The incidence of CH in 2015 was 1 ∶ 1 312,and 73.5％ (61/83 cases) of CH patients were classified as SDH.Compared with those founded in 2011-2012,the incidence of CH was increased (1 ∶ 1 312 vs.1 ∶ 2 779),and the difference was significant (P ＜ 0.001),while the frequency of SDH was not different significantly (73.5 ％ vs.76.6％,P =0.593).(2) There were 27 cases (51.9％) with SDH detected DUOX2 hotspots variants,including 6 cases with biallelic variants,21 cases with monoallelic variants,and 1 possible new pathogenic variant p.S1091F.The p.K530X was the most common mutation accounting for 51.5％ (17/33 cases) detected allelic and involving in 16 cases (30.8％) with SDH.Novel p.S1091F variant was probably damaging variant.Both detected rate and spectrum of DUOX2 variant were not significantly different compared with those in 2011-2012 (all P ＞ 0.05).(3) There were no significant differences in the levels of thyrotropin (bsTSH),serum TSH (sTSH),free thyroxine (FT4) and thyroglobulin in neonates with dry blood spot at diagnosis between children with DUOX2 and without DUOX2 variants cases (all P ＞ 0.05).Among 27 cases,24 (88.9％) patients with DUOX2 mutation were transient CH,and 3 cases were permanent CH.Conclusions The incidence of CH was increased in last few years in Guangzhou.Most of them were SDH,and 51.9％ of SDH cases had DUOX2 hotspots variants.Temporary CH is the main clinical outcome.The p.K530X was the most common mutation in this cohort population.

DUOX2 hotspots variants and outcomes of patients with congenital hypothyroidism suspected thyroid dyshormonogenesis / 中华实用儿科临床杂志

Objective@#To investigate prospectively molecular and clinical characteristics of infants with congenital hypothyroidism (CH) caused by DUOX2 mutations in Guangzhou.@*Methods@#A population-based cohort of 83 patients with CH were recruited based on newborn screening results among 108 899 newborns who were born in Guangzhou between April 1 and September 30 in 2015.Genetic analysis of DUOX2 hotspots(including 11 exons)by PCR-direct sequencing was performed in 52 patients with suspected thyroid dyshormonogenesis (SDH) according to thyroid ultrasound at diagnosis.All the patients were followed up for 3 years.The data of this cohort study(prevalence of CH, detection rate of DUOX2, clinical features) were compared with those of 96 patients with SDH in 2011-2012.@*Results@#(1) The incidence of CH in 2015 was 1∶1 312, and 73.5%(61/83 cases) of CH patients were classified as SDH.Compared with those founded in 2011-2012, the incidence of CH was increased (1∶1 312 vs.1∶2 779), and the difference was significant (P<0.001), while the frequency of SDH was not different significantly (73.5%vs.76.6%, P=0.593). (2)There were 27 cases(51.9%) with SDH detected DUOX2 hotspots variants, including 6 cases with biallelic variants, 21 cases with monoallelic variants, and 1 possible new pathogenic variant p. S1091F.The p. K530X was the most common mutation accounting for 51.5%(17/33 cases) detected allelic and involving in 16 cases (30.8%) with SDH.Novel p. S1091F variant was probably damaging variant.Both detected rate and spectrum of DUOX2 variant were not significantly different compared with those in 2011-2012 (all P>0.05). (3) There were no significant differences in the levels of thyrotropin (bsTSH), serum TSH (sTSH), free thyroxine (FT4) and thyroglobulin in neonates with dry blood spot at diagnosis between children with DUOX2 and without DUOX2 variants cases(all P>0.05). Among 27 cases, 24(88.9%) patients with DUOX2 mutation were transient CH, and 3 cases were permanent CH.@*Conclusions@#The incidence of CH was increased in last few years in Guangzhou.Most of them were SDH, and 51.9% of SDH cases had DUOX2 hotspots variants.Temporary CH is the main clinical outcome.The p. K530X was the most common mutation in this cohort population.

Newborn screening program and blood amino acid profiling in early neonates with citrin deficiency / 中华儿科杂志

Objective@#To investigate the profiles of blood amino acid and acylcarnitine in early neonates with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and the sensitivity of newborn screening, and to explore potential biochemical metabolic markers for newborn screening program.@*Methods@#Amino acid and acylcarnitine profiles in dried blood spots of newborn screening program were analyzed by tandem mass spectrometry (MS/MS). A total of 158 651 neonates born in Guangzhou from January 1, 2015 to June 30, 2019 were enrolled in this newborn screening program, and additionally 55 patients with NICCD confirmed by SLC25A13 gene analysis in Guangzhou Women and Children Medical Center were included in this study. NICCD screen-positive was defined as the cutoff value of citrulline (Cit) ≥ 30 μmol/L. The values of blood sampling time of the true positive group and those of the false negative group were compared by t-test. The levels of amino acid and acylcarnitine among different groups, including true positive group (Cit≥30 μmol/L), false negative group (Cit 21-<30 μmol/L and Cit<21 μmol/L) and the normal control group, were analyzed by F test, respectively.@*Results@#Among 158 651 neonates, 39 neonates were positive for NICCD screening. Three of them were confirmed NICCD and 4 cases were found to be false negatives. The positive predictive value was 7.7% and the sensitivity was about 43.0%. Among 55 patients with NICCD, 18 cases (18/55, 32.7%) were true positives and 37 cases (37/55, 67.3%) were false negatives based on the cutoff value of citrulline in the dried blood spots for newborn screening. The blood sampling time was significantly different between true positive group and false negative group ((4.28±1.6) vs. (2.98±0.74) d, t=4.06, P<0.01). The increased levels of tyrosine((176.0±98.4) μmol/L), methionine ((37.0±26.9) μmol/L) and phenylalanine ((133.0±80.9)μmol/L) in Cit≥30 μmol/L group (n=18) were significantly different as compared with those in the other three groups, respectively (F=117.0, 58.5, 135.0, P<0.01). The levels of arginine ( (10.0±9.2) , (11.0±9.3) , (9.0±17.8) μmol/L), valine ( (119.0±29.8) , (107.6±14.1) , (102±68) μmol/L) and leucine ( (167.0±37.1) , (161.0±37.7) , (163.5±180.6) μmol/L) were not statistically significant among groups of Cit≥30 μmol/L(n=18), Cit21-<30 μmol/L(n=7) and Cit<21μmol/L(n=30,P>0.05), but they were significantly higher than those of the normal control group ((4±3), (78±21), (114.0±31.5) μmol/L, n=1 000), respectively(F=30.1, 23.0, 29.8, P<0.01). Alanine (Ala) ( (150±50) , (156.0±30.2), (168±105), (152±52) μmol/L) levels showed no significant difference (F=0.86, P>0.05) but the ratios of Ala/Cit (1.52±1.44, 6.82±1.56, 12.06±7.71, 19.42±6.27) decreased significantly among the four groups (F=69.0, P<0.05). The acylcarnitine levels showed no statistically significant results among the different groups (P>0.05). With Cit≥30 μmol/L and Ala/Cit<7.5 as cutoff values, the number of screen-positive cases reduced from 39 to 22 cases with no additional false negative case. With Cit≥21 μmol/L and Ala/Cit<7.5 as cutoff values the number of screen-positive cases increased to 117 cases with 1 additional true positive.@*Conclusions@#The profiles of blood amino acid in early neonates with NICCD present the increased levels of multiple amino acids including citrulline, tyrosine, methionine and phenylalanine, and decreased ratio of Ala/Cit. Taking citrulline and ratio of Ala/Cit as screening markers can improve the positive predictive value appropriately. The limited sensitivity of NICCD newborn screening may be related to early blood sampling time.

Pilot study on the adjustment of the cut-off value for congenital hypothyroidism screening according to the age at sampling / 中国新生儿科杂志

Objective To study the influence of postnatal age and season of sample collection on congenital hypothyroidism (CH) screening and to determine the appropriate cut-off value. Method From January 2015 to December 2017, neonatal thyroid stimulating hormone (TSH) screening data in Guangzhou were retrospectively analysed. The infants were assigned into four groups according to sampling postnatal age:24～＜48 h, 48～＜72 h, 3～＜7＜d and≥7 d, and assigned into another four groups according to their birth seasons. Based on the data of 2015 and 2016, the cut-off value of TSH for hypothyroidism were adjusted. The data of 2017 were used to verify the accuracy of the adjusted cut-off value. The cut-off value was determined based on the receiver operating characteristic (ROC) curve and percentile method. Specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) of the cut-off value were also calculated. Result A total of 459854 newborns were screened from 2015 to 2016. 7329 were positive in preliminary screening, 371 were still positive after recall for re-examination, and 318 were confirmed with CH eventually. The optimal TSH cut-off value calculated using ROC curve was 9 mIU/L, with a percentage of 98.7. The cut-off value with sampling time≥48 h was set to 9 mIU/L in spring, summer and autumn, and 10 mIU/L in winter. The cut-off of sampling time 24～＜48 h was set to 10 mIU/L in all seasons. The data of 264993 newborns screened in 2017 were verified using the adjusted cut-off value. The overall positive rate was reduced from 1.27％to 1.02％, and the PPV was increased from 6.07％to 7.58％without adding false negative cases. Conclusion Adjusting cut-off values of TSH for CH screening according to postnatal age and season can effectively reduce false positive rates.

Clinical features and genetics studies of Finnish variant late infantile neuronal ceroid lipofuscinosis in two families / 中华儿科杂志

Objective@#To report clinical feature and results of genetic analysis of 3 patients from 2 families with Finnish variant late infantile neuronal ceroid lipofuscinosis.@*Methods@#The clinical and ultrastructural features of 3 patients with progressive neurodegenerative diseases were retrospectively analyzed from October 2014 to December 2016 in Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center. The whole exon sequencing and Sanger sequencing were used to analyze the molecular genetics of the patients and their parents.@*Results@#The probands were 11 years and 3 moths, 9 years and 1 month,10 years and 1 month old. All were normal at birth, and from 5-6 years old they began to develop "regression of cognition and motion, impaired vision". Physical examination at the first consultation: clear minded butignorant, unable to speak and understand instructions, unable to stand up and sit alone, unable to maintain postureupright. The brain magnetic resonance imaging(MRI) indicated diffuse cerebral and cerebellar atrophy, white matter damage. Blood biochemistry, lactic acid, acid-base balancewere normal. Electron microscopic examination of peripheral blood lymphocytes showed swelling of the nucleus, autophagy, intracellular massive deposits and abnormal vacuoles. Two compound heterozygous c.334C> T (p.Arg112Cys) and c.595C> T (p.Arg199Ter) mutations of CLN5 gene were identified in the two siblings, and the proband 3 was c.335G> A (p.Arg199His) homozyousmutation, which were inherited from their unaffected parents.@*Conclusions@#The 3 cases with Finnish variant late infantileneuronal ceroid lipofuscinosises were normal at birth, cognitive and motor function was regressed at preschool age.Brain MRI showed whole brain atrophy, white matter lesions, there were no bovious difference from other neurodegenerative diseases. Blood biochemistry and pathological examination of lymphocytes had no specific changes. The pathogenic genes were CLN5,most are inherited in autosomal recessive way.

Evaluations of newborn screening program performance and enzymatic diagnosis of glucose-6-phosphate dehydrogenase deficiency in Guangzhou / 中华儿科杂志

Objective@#To reveal the molecular epidemiologic characteristics of glucose-6-phosphate dehydrogenase (G6PD) gene and to evaluate based on the genetic analysis the newborn screening program performance and enzymatic diagnosis of G6PD deficiency in Guangzhou.@*Methods@#G6PD enzyme activities were measured by quantitative fluorescence assay in dry blood spots of 16 319 newborns(8 725 males, 7 594 females) 3-7 days after birth in Guangzhou Newborn Center. They were born in Guangzhou form Oct. 1 to 20, 2016. The cutoff value of G6PD was less than 2.6 U/g Hb in dry blood spots. G6PD deficiency was diagnosed when G6PD<1 700 U/L or G6PD/6PGD<1 in red blood cells. Genetic analysis of G6PD gene was performed on the dry blood spot samples of 823 newborns (including positive 346, negative 477)with various levels of G6PD enzyme activities through fluorescence PCR melting curve analysis(FMCA) to detect 15 kinds of mutations reported to be common among Chinese.G6PD gene Sanger sequency was performed in seven highly suspicious patients with negative results by FMCA.@*Results@#(1) Using the cutoff value of G6PD< 2.6 U/g Hb , a total of 687(4.2%) newborns showed positive screening results, including 560 (6.4%) males and 127(1.7%) females. (2) Among the newborns with positive screening results, 214 males and 122 females were randomly chosen for G6PD gene analysis. The results showed that 197 (92.1%) males were hemizygote and 108(88.6%) females were mutation carriers with one to four alleles. Among the newborns with negative screening results, 41 males with G6PD 2.6-2.8 U/g Hb and 436 females with G6PD 2.6-4.5 U/g Hb were chosen for genetic analysis.Mutations were detected in 5(12.2%)boys, and 226(51.8%) girls were carriers.G6PD gene Sanger sequency of seven highly suspicious patients showed that c.406C>T, c.551C>T, c.835A>T hemizygote were found in 3 male's samples, respectively. (3) The estimated prevalence of harboring mutation was 6.0% in males and 13.5% in females according to rates of mutation in samples with various levels of G6PD enzyme activities. Six common mutations were c.1388G>A、c.1376G>T, c.95A> G, c.871G>A, c.1024C>T, c.392G>T, accounting for 95.5% of detected alleles .(4) based on results of G6PD gene analysis, the newborn scereening of G6PD deficiency with cutoff value G6PD<2.6 U/g Hb yielded a positive predict value(PPV) of 93.5%, a false-positive rate of 0.5%, and a sensitivity of 99.0% for males. A PPV of 88.5%, a false-positive rate of 0.2% . The prevalence of severe type G6PD deficiency in females was about 1.5%. Compared with to genetic analysis, the sensitivity and PPV of G6PD activity assay in red blood cells were 95.5%, 97.2%, respectively.@*Conclusions@#The prevalence of G6PD deficiency in males was 6.0% in Guangzhou. Six mutations c.1388G>A, c.1376G>T, c.95A>G, c.871G>A, c.1024C>T, c.392G>T accounted for 95.5%. The cutoff value of G6PD<2.6 U/g Hb innewborn screening program and the criteria of biochemical diagnosis could accurately identify G6PD deficiency . Combined with biochemical and molecular analysis will improve the accuracy of diagnosis of G6PD deficiency and detect more heterozygous females.

High risk screening and disease spectrum for 24 kinds of lysosomal storage diseases / 中华实用儿科临床杂志

Objective To evaluate the sensitivity and specificity of enzyme assays,and to provide disease spectrum of lysosomal storage diseases (LSDs).Methods Three thousand three hundred and sixty-four high risk individuals were screened for 24 LSDs at Guangzhou Women and Children's Medical Center between January 2009 and December 2016.Twenty-two kinds of enzyme activities from peripheral blood leucocytes or plasma were measured by using the fluorometry or colorimetry of corresponding artificial substrates,screening for 24 LSDs diseases.Measurement data were represented by (x) ± s,and count data were expressed as a percentage or composition ratio.Results A total of 283 subjects were diagnosed with 18 different kinds of LSDs,and the positive rate of high-risk screening was 8.4％.Among the identified patients,172 cases (60.8％) were mucopolysaccharidosis (MPS),79 cases (27.9％) were sphingolipidoses,18 cases (6.4％) were Pompe diseases,10 cases (3.5％) were affected with mucolipidoses,3 cases (1.1％) were glycoprotein storage diseases,and 1 case(0.4％) was Wolman disease.Of the MPS cases,there were 75 cases of MPS Ⅱ (43.6％),45 cases of MP5 ⅣA (26.2％),24 cases of MPS Ⅵ (14.0％) and 20 cases of MPS Ⅰ (11.6％).Gaucher disease (23/79 cases,29.1％) and metachromatic leukodystrophy (MLD) (21/79 cases,26.6％) were common in sphingolipidoses group.Both the sensitivity and specificity of enzyme assays on peripheral blood leucocytes for LSDs were 100％.Conclusions The most common kinds of LSDs are MPS Ⅱ,MPS Ⅳ A,MPS Ⅵ,Gaucher disease,MLD and Pompe disease.Leukocyte enzymology analysis of high-risk screening LSDs has high sensitivity and specificity.

Genetic analysis of TPO, DUOX2 and DUOXA2 genes in children with permanent congenital hypothyroidism suspected dyshormonogenesis / 中华儿科杂志

Objective@#To explore the TPO, DUOX2 and DUOXA2 genotypes and phenotypes of children with permanent congenital hypothyroidism(PCH) suspected dyshormonogenesis in Guangzhou, identified and treated at Guangzhou Newborn Screening Center. Six of them were born between 2011 and 2012.@*Method@#Retrospectively analyzed the clinical data of 9 children with PCH suspected dyshormonogenesis. Genetic analysis of TPO, DUOX2 and DUOXA2 genes were performed with Sanger sequencing.@*Result@#Of the 9 patients, four were identified variants in TPO gene including three cases with biallelic variants and one case with monoallelic variant. Novel c. 1784G>C( p. R595T) variant in TPO was predicted to be damaging by SIFT and PolyPhen-2. Four patients harbored monoallelic known variants in DUOX2 gene and the other one harbored heterozygous known mutation c. 738C>G(p.Y246X) in DUOXA2 gene.Two adolescent patients with biallelic variants in TPO gene showed classical PCH phenotypes with thyroid goiter or nodules. The six patients with monoallelic variant in TPO, DUOX2 or DUOXA2 presented variable phenotypes. Among the 433 578 newborns in the 2011-2012 cohort, there were 156 cases of CH. Six of these cases were PCH suspected dyshormonogenesis, among which 1 case was confirmed TPO biallelic variants and 5 cases were monoallelic variants of TPO, DUOX2, or DUOXA2 genes.@*Conclusion@#TPO and DUOX2 variants are the common molecular pathogenesis in children with PCH suspected dyshormonogenesis. Monoallelic variants in TPO, DUOX2 or DUOXA2 are associated with PCH and showed wide variability in their phenotypes. The novel variant p. R595T in TPO is probably a pathologic variant. The prevalence of PCH caused by TPO gene defects is rare in Guangzhou.

Study on iodine nutrition and thyroid function in pregnant women / 国际检验医学杂志

Objective To analyze iodine nutrition and its correlation with thyroid function in pregnant women.Methods A total of 295 pregnant women were enrolled from Jun.to Oct.2016,and detected for serum levels of thyroid stimulating hormone(TSH),free thyroxine(FT4) and thyroid-peroxidase antibody(TPOAb) by using electrochemiluminescence analysis,and for urinary iodine concentration(UIC) by cold digestion method according to iodine catalytic effect of arsenic-cerium.Results The median of UIC was 174.90 μg/L.The prevalence of iodine deficiency and iodine excess were 40.00% and 7.12% respectively.The prevalence of TPOAb positivity and thyroid dysfunction in the iodine deficiency group and iodine excess group were significantly higher than those of iodine proper group(P<0.05).The levels of TSH and FT4 of iodine excess group were significantly higher than those of iodine proper group(P<0.05).Conclusion The abnormality of iodine nutrition could be common in pregnant women.Monitoring of UIC and thyroid hormones should be highlighted.

Clinical and molecular analysis of two Chinese siblings with Cockayne syndrome / 中华儿科杂志

<p><b>OBJECTIVE</b>Cockayne syndrome is a rare disease and difficult to be recognized. This study aimed to expand the knowledge of the clinical and molecular characteristics of the children with Cockayne syndrome (CS).</p><p><b>METHOD</b>Clinical data of two siblings with classic CS of Guangzhou Women and Children's Medical Center from July 2013 to November 2014 were obtained and analyzed. The whole DNA of peripheral blood was collected from two CS siblings and their parents. Amplification of all exons and adjacent introns for ERCC6 gene was conducted using PCR, and measurement of reaction product was performed to find mutation sites by two-way sequencing.</p><p><b>RESULT</b>Two affected siblings were males, and came from unconsanguineous parents, 7 years and 5 months old and 4 years and 8 months old, respectively. They were in treatment because of developmental and mental retardation for years. When they were younger than one year of age, their heights and weight were within normal limits. However, poor growth of height and weight and psychomotor retardation appeared after one and a half years of age, as well as skin and eye sensitivity to sunshine, hearing impairment, optic nerve atrophy, microcephaly, and deep-set eyes. The proband's height was 90.8 cm, and weight 9.1 kg, head circumference 41 cm, and chest circumference 44 cm when he was taken to hospital. The elder brother of the proband had a height of 92 cm, weight 11.2 kg, head circumference 41 cm, and chest circumference 44 cm when he was taken to hospital. When the proband was four and a half years old, ventricular enlargement, hypomyelination, and brain atrophy were detected for his elder brother at 7 years of age by cranial MRI. MRS imaging indicated that damages occurred at the left and right sides of dorsal thalamus, lobus insularis, along with the left half circle of central neurons. Symmetrical calcification on bilateral basal ganglia was found on the brain CT scan. Pathogenic compound heterozygous c. 1357C > T (p.Arg453Ter) and c. 1607T > G (p.Leu536Trp) mutations of ERCC6 gene were identified in the two siblings which were separately inherited from their unaffected parents.</p><p><b>CONCLUSION</b>CS children are usually normal at birth, however, they have severe clinical characteristics such as poor growth, psychomotor retardation, cerebral injury, microcephalus, deep-set eyes, and skin sensitivity to sunshine. ERCC6 gene mutation usually occurs, and it is easy to misdiagnose CS as cerebral palsy, primary microcephaly, and so on.</p>

Clinical and molecular characteristics of 27 children with Prader-Willi syndrome in South China / 中华实用儿科临床杂志

Objective To understand the clinical and molecular characteristics of children with Prader-Willi syndrome (PWS) in South China.Methods Clinical and molecular data of children diagnosed as PWS by Methylation-specific PCR(MS-PCR) and/or Array Comparative Genomic Hybridization(Array-CGH)in Guangzhou Women and Children's Medical Center from November 2012 to November 2014 were analyzed.Results A total of 27 children diagnosed as PWS were included in this study,including 21 cases diagnosed by Array Comparative Genomic Hybridization (Array-CGH) and 13 cases diagnosed by methylation-specific PC R (MS-PCR).Within the 27 cases,13 cases were male(48.1％) and 14 cases were female(51.9％).The age on diagnosis was from 16 days to 16 years old.MS-PCR was performed in 13 cases,7 cases of them also performed Array-CGH,both of them showed a 174 bp fragment from the methylated allele and a 100 bp fragment from the unmethylated allele.Array-CGH analysis was performed in 21 cases,paternal deletion in 18 cases and mean interstitial deletions measure (5.48 ± 0.51) Mb in size,paternal duplication in 2 cases,loss of heterozygosity measure approximately 79.58 Mb in 1 case.Eighteen simple chromosome deletion cases were divided into 6 Del Ⅰ and 12 Del Ⅱ according to the location of Array-CGH and query the database to DECIPHER(Database of Chromosomal Imbalance and Phenotype in Humans Using Ensembl Resources).The major phenotype included central hypotonia and feeding difficulty in all cases (100.0％),hypogonadism in 25 cases (92.6％),weak crying in 22 cases(81.5％),and hypopigmentation in 22 cases(81.5％).Fourteen cases beyond 1 year old had varied degrees of development disability and behavioral and psychiatric disturbance:speech articulation defects in 13 cases(92.9％),hyperphagia and weight gain too fast in 13 cases(92.9％) when they were between 1 to 6 years old[(2.80 ± 1.32) years old],and obesity in 12 cases (85.7％).Conclusions For PWS children in South China,there is no statistically significant difference in the clinical manifestation between Del Ⅰ and Del Ⅱ.PWS children in South China have typical clinical characteristics,which can be used as a further screening indication to implement molecular diagnostics.

Clinical research on methimazole treatment of 379 children with hyperthyroidism at a single institution / 中华内分泌代谢杂志

Objective To investigate the clinical efficacy and adverse events of methimazole ( MMI ) treatment for children with hyperthyroidism, and to identify the predictors of remission and relapse. Methods A total of379children(260girlsand119boys)diagnosedwithhyperthyroidismandtreatedbyMMIinGuangzhouWomenand Children's Medical Center from March, 2004 to July, 2014 were retrospectively analyzed. The average age at diagnosiswas(9.3±2.3)years(range2.0~15.9years). Results AftertreatmentwithMMIfor3and6months, the thyroid functions of 96. 3%(365/379) and 98. 9%(375/379) patients returned to normal, respectively. By the end of this study, 256(67. 5%) patients continued to use MMI treatment and 44 patients(11. 6%) dropped out. 79 patients(20. 8%) achieved remission, 35 patients (44. 3%) of whom experienced a later relapse. Children who achieved constant remission had significantly lower FT3 and FT4 levels at diagnosis compared with the relapsed children(P<0. 05 or P<0. 01). It was more likely to remain long-term remission for children turned to be euthyroid within 3 months after initiating MMI treatment(P<0. 05). The relieved patients with family history of thyroid diseases weremorelikelytoberelapsed(P<0.05). Therewerenosignificantdifferencesinage,gender,exophthalmos, initial goiter size, thyroid peroxidase autoantibody, and thyroglobulin antibody levels between the relieved and relapsed patients. The overall incidence of adverse events associated with MMI was 27. 7%, mainly elevated alanine aminotransferase, bilirubin, and neutropenia. Most(66. 7%) of adverse events occurred within the first three months of MMI treatment. Conclusion MMI has a good effect on pediatric hyperthyroidism, with low remission and high relapse rate. The low thyroid hormone concentrations at diagnosis and normalization of thyroid function within three months seem to be useful predictors of remission. Vigilance is needed concerning MMI-associated adverse events throughout the MMI treatment period, especially during the first trimester of MMI initiation.

Kniest dysplasia due to mutation of COL2A1 gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutation of COL2A1 gene in two children suspected for Kniest dysplasia.</p><p><b>METHODS</b>The 54 exons and splicing regions of the COL2A1 gene were amplified with PCR and the product was subjected to direct sequencing.</p><p><b>RESULTS</b>A missense mutation (c.905C>T, p.Ala302Val) was found in the coding region of the COL2A1 gene, which has been previously reported in abroad. The patients appeared to have short trunk dwarfism, enlarged joints and midface hypoplasia.</p><p><b>CONCLUSION</b>The probands are the first cases of Kniest dysplasia described in China, and so was the p.Ala302Val mutation.</p>

Analysis of screening results for congenital hypothyroidism in preterm infants / 中国基层医药

Objective To discuss the effect of neonatal congenital hypothyroidism (CH)screening in preterm infants.Methods The result of 208 713 cases neonatal congenital hypothyroidism screening in Guangzhou neonatal screening center were analyzed,including 11589 cases preterm infant and 197 124 cases of full term.The difference of screening positive rate and incidence between preterm infants and full term infants group were compared and the efficiency of preterm infants congenital hypothyroidism screening were estimated.Results A total of 208 713 newborns were screened and the screening positive rate was 1.39%.123 cases were confirmed positive for CH and the incidence rate was 1 /1 697.124 cases were screening positive in preterm infants and the screening posi-tive rate was 1.06%.14 cases were confirmed positive for CH and the incidence rate was 1 /828 in preterm infants group.2 771 cases were screening positive in full term infants and the screening positive rate was 1.41%.109 cases were confirmed positive for CH and the incidence rate was 1 /1 809 in full term group.The screening positive rate was lower and the incidence rate of preterm infants group(χ2 =4.89,P <0.05)was higher than that of the full term infants group(χ2 =8.26,P <0.05).Conclusion The incidence rate of congenital hypothyroidism is higher in preterm infants.Neonatal screening is an effective measure for early diagnosis of preterm infants congenital hypothyroidism.

The application of colostomy care products in managing the leakage around PTCD drainage tube / 介入放射学杂志

Objective To investigate the application of colostomy care products in managing the leakage around PTCD drainage tube, and to discuss its clinical effect. Methods A total of 56 patients with malignant obstructive jaundice, who had received PTCD and suffered from postoperative leakage around PTCD drainage tube, were randomly and equally divided into the study group (n=28) and the control group (n=28). The colostomy care powder, the skin protective film and the colostomy bag were used for the patients of the study group, while iodophors, sterile gauze and mupirocin ointment were employed for the patients of the control group. The incidence of irritant dermatitis around PTCD drainage tube, the degree of comfort to the indwelling tube judged by the patient, and the nursing workload for PTCD drainage tube were determined, and the results were compared between the two groups. Results The incidence of irritant dermatitis around PTCD drainage tube in the study group was obviously lower than that in the control group. And the degree of comfort to the indwelling tube judged by the patient in the study group was much higher than that in the control group. The differences between the two groups were statistically significant (P<0.05). Conclusion Combination use of colostomy care powder, skin protective film and colostomy bag can effectively reduce the incidence of irritant dermatitis around PTCD drainage tube and improve the patient’s condition. Therefore, this method is worthy of popularization in clinical practice.

Analysis of clinical features and arylsulfatase B gene mutation in thirteen Chinese children with mucopolysaccharidosis type VI / 中华儿科杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type VI (MPS VI) or Maroteaux-Lamy syndrome is an autosomal recessive lysosomal storage disease caused by a deficiency of arylsulfatase B(ARSB), which is required in the degradation of dermatan sulfate and chondroitin sulfate. The deficiency of ARSB leads to an accumulation of dermatan sulfate and chondroitin sulfate in lysosomes and gross excretion in the urine.Few articles about clinical study and ARSB gene mutation analysis of Chinese MPS VI patients were published. This study aimed to explore the clinical features and characteristics of ARSB gene in Chinese children with MPS VI.</p><p><b>METHOD</b>Thirteen children were diagnosed as MPS VI by ARSB enzyme activity determination during the period from 2009 to 2013. Their clinical features, radiological findings and urine glycosaminoglycan (GAG) levels were retrospectively reviewed. Direct sequencing was used to identify any mutation in the ARSB gene.</p><p><b>RESULT</b>Thirteen children were diagnosed at the average age of (3.9 ± 2.2) years with 6 male and 7 female. All of these children presented with severe form and onset at an early age of (1.5 ± 0.8) years.Other clinical features included coarse facies, short stature, skeleton deformity, corneal clouding, hepatosplenomegaly with normal intelligence. The radiological findings in all children were characteristic of dysostosis multiplex, like abnormal development of vertebral bodies of the spine, campylorrhachia and paddle-shaped widened ribs. The MRI in case 2 showed cervical cord compression and multiple cysts degeneration in the corona radiate, cella lateralis and callosum.High urine GAG levels were detected, (307.10 ± 112.14) mg/L (Normally below 70 mg/L) and (722.28 ± 245.68) µg/mg creatinine. The ARSB enzyme activity in leukocytes was low, (13.29 ± 6.22) nmol/(mg×h) [Normal range (47-169) nmol/(mg×h)] by fluorogenic assay and (0.24 ± 0.18) U/g [Normal range (1.01-11.47) U/g] by colorimetric assay. A total of 11 mutations were identified by molecular analysis, including seven previously reported mutations (p.L72R, p.G167R, p.G303E, p.F399L, p. T442M, p.Y255X and p.R327X) and four novel mutations (p.Y175D, p.S403X, p.S464X and large deletion including ex. 2, 3). The c.1197C>G (p.F399L) mutation was the most common mutation in this study (31%).</p><p><b>CONCLUSION</b>The severe form of MPS VI is characterized by early onset and rapid illness progression. Both the radiological findings and increased urine GAG are important clues to diagnose MPS VI.Large decrease or absence of ARSB activity is diagnostic for MPS VI.Four novel mutations of ARSB gene were identified. The reported mutation c.1197C>G (p.F399L) was the hot-spot mutation in this study.</p>

Clinical and molecular characteristics of a child with juvenile Sandhoff disease / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the clinical features and molecular mutation of HEXB gene in a case with juvenile Sandhoff disease.</p><p><b>METHOD</b>We retrospectively reviewed the clinical, neuroimaging and biochemical findings in this Chinese child with juvenile Sandhoff disease. Hexosaminidase A and hexosaminidase A & B activities were measured in blood leukocytes by fluorometric assay. HEXB gene molecular analysis was performed by PCR and direct sequencing.</p><p><b>RESULT</b>The 9-year-old boy was admitted for psychomotor regression. He presented slowly progressive gait disorder and dysarthria during the last three years. Cranial MRI revealed a marked cerebellar atrophy with normal intensity in the thalamus and basal ganglia. Brain MRS showed normal in the thalamus and basal ganglia. Hexosaminidase A was 69.5 (mg·h) [normal controls 150-360 nmol/(mg·h)], hexosaminidase A & B activity was 119 nmol/(mg·h)[normal controls 600-3 500 nmol/(mg·h)], confirming the diagnosis of Sandhoff disease. The patient was a compound heterozygote for a novel deletion mutation c.1404delT (p. P468P fsX62) and a reported mutation c.1509-26G>A.</p><p><b>CONCLUSION</b>The clinical features of juvenile Sandhoff disease include ataxia, dysarthria and cerebellar atrophy. The enzyme assay and molecular analysis of HEXB gene can confirm the diagnosis of Sandhoff disease. The novel mutation c.1404delT(p. P468P fsX62) is a disease-related mutation.</p>