Analysis of clinical phenotypes and ATP7B gene variants in 75 children patients with Wilson' s disease / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotypes and ATP7B gene variants among children patients with Wilson' s disease from Northwestern China.@*METHODS@#The clinical features and variants of the ATP7B gene among 75 children with hepatic Wilson' s disease were retrospectively analyzed.@*RESULTS@#Among the 75 cases, 4 were presymptomatic, 59 had isolated transaminase elevation, 12 had acute and/or chronic liver diseases. Nine children were found to harbor homozygous variants, 64 harbored compound heterozygous variants, and two only had heterozygous variants of the ATP7B gene. In total 49 variants were detected, with common variants including c.2333G>T (p.Arg778Leu), c.2621C>T (p.Ala874Val) and c.2975C>T (Pro992Leu), which yielded allelic frequencies of 28.7%, 12.7% and 9.3%, respectively. Six novel variants were detected, which included c.1908dupC (p.Asn637Glnfs*118), c.4179_4180insC (p.Pro1394Profs*15), c.1604A>G (p.Glu535Gly), c.2278C>T (p.Pro760Ser), c.3008C>A (p.Ala1003Glu) and c.3532A>C (p.Thr1178Pro). Except for c.1604A>G (p.Glu535Gly), the remainder five were all predicted to be likely pathogenic. No significant correlation was found between genotype and phenotype among the patients.@*CONCLUSION@#The common mutation types of the ATP7B gene among patients with hepatic Wilson disease in Northwestern China are c.2333G>T (p.Arg778Leu), c.2621C>T (p.Ala874Val) and c.2975C>T (p.Pro992Leu), there is no significant correlation between their genotypes and phenotypes.

Analysis of a novel JAG1 variant and clinical phenotype in a family affected with Alagille syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a pedigree affected with Alagille syndrome (ALGS).@*METHODS@#Targeted capture and next generation sequencing was carried out for the proband. Candidate variants were verified by Sanger sequencing among his family members. Their pathogenicity of the variant was predicted with bioinformatic analysis. Clinical characteristics and genotype-phenotype correlation were analyzed.@*RESULTS@#The proband, his elder sister and mother were found to carry a heterozygous c.1270dupG (p.Ala424Glyfs*5) variant of the JAG1 gene, which may lead to premature termination of translation and a truncated protein with loss of function. The variant was unreported previously. The phenotypes of the proband (cholestasis, pulmonary artery stenosis and peculiar faces) have differed from those of his elder sister (cholestasis with pruritus, posterior embryonic ring of cornea) and mother (with no clinical manifestation). Cholestasis and peculiar face of the proband became insignificant with age.@*CONCLUSION@#The c.1270dupG (p.Ala424Glyfs*5) variant of the JAG1 gene probably underlay the ALGS in this pedigree with incomplete penetrance.

Isovaleric acidemia due to compound heterozygous variants of IVD gene in a case / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical features, biochemical characteristics and molecular pathogenesis of a girl with isovaleric acidemia.@*METHODS@#Clinical features, blood spot amino acid profiles and urinary organic acid profiles of the patient were analyzed. Targeted capture, next generation sequencing and Sanger sequencing were carried out to detect potential variant of the IVD gene.@*RESULTS@#The patient presented with poor weight gain, poor feeding, lethargy, and a "sweaty feet" odor 10 days after birth. Biochemical test suggested hyperammonemia. Blood spot amino acid profiles displayed a dramatic increase in isovalerylcarnitine (C5: 3. 044, reference range 0.04 - 0.4 μmol/L). Organic acid analysis of her urine sample revealed a high level of isovaleric glycine (669. 53, reference range 0 - 0.5). The child was ultimately diagnosed with isovaleric acidemia, and was found to harbor a paternally derived heterozygous variant c.149G>A (p.R50H) and a maternally derived heterozygous variant c.1123G>A (p.G375S) of the IVD gene. Her elder brother was a heterozygous carrier of c.1123G>A (p.G375S) variant. The c.149G>A (p.R50H) was a known pathogenic variant, while the c.1123G>A (p.G375S) variant was previously unreported.@*CONCLUSION@#The pathogenesis of the patient was delineated from the perspective of genetics, which has provided a basis for clinical diagnosis, treatment as well as genetic counseling.

Analysis of clinical characteristics and SLC25A13 gene mutation in children with neonatal intrahepatic cholestasis caused by citrin deficiency / 国际儿科学杂志

Objective:To analyze the clinical characteristics and SLC25A13 gene mutation in children with neonatal intrahepatic cholestasis caused by citrin deficiency(NICCD).Methods:The data of 18 children diagnosed with NICCD in Xi′an Children′s Hospital from January 2014 to December 2018 were collected.The clinical manifestations, biochemical characteristics, SLC25A13 gene mutation and prognosis were analyzed.Results:All the 18 cases of NICCD were from North China and the age of initial diagnosis averaged(63.4±19.5)days.The clinical manifestations included jaundice(100%), light yellow or white stool(38.9%), growth retardation(27.8%)and so on.All patients had cholestasis.Of 18 cases, the levels of glutamyltranspeptidase, total bile acid and alpha fetoprotein were all increased, and serum albumin was decreased.Elevated aspartate aminotransferase(94.4%), elevated glutamic pyruvic transaminase(72.2%), prolonged prothrombin time(88.9%), hyperlactemia(83.3%), hypoglycemia(77.8%), anemia(66.7%)and other biochemical abnormalities were observed.Citrulline and other serum amino acids of all cases were elevated in blood samples by tandem mass spectrometry.The increase of 4-hydroxyphenyllactate and 4-hydroxyphenylpyruvate was found in 70%(7/10)urine samples by gas chromatography.Age was negatively correlated with total bile acid( r=-0.469, P=0.049), and positively correlated with blood ammonia, threonine, methionine, ornithine and tyrosine( r=0.472, 0.690, 0.698, 0.678 and 0.769, respectively, P<0.05). A total of 16 SLC25A13 gene mutations were detected, of them c. 851_854del(33.3%)and c. 1638_1660dup(19.4%)were the most common.c.1841+ 3_1841+ 4del, c.980_981del(p.E327Vfs*45)and c. 602A>T(p.E201V)were novel mutations.Among the 17 children who were followed up, 1 case died and 16 cases had normal biochemical parameters within 1 year. Conclusion:The characteristic biochemical changes are helpful for early recognition of NICCD.The prognosis of NICCD is good if the treatment is appropriate and timely.c.851_854del and c. 1638_1660dup are high-frequency mutations of SLC25A13 gene in north China.

Identification of a novel variant of SRD5A2 gene in a child featuring steroid 5α-reductase type 2 deficiency / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics and genetic basis of a child with 5α-reductase type 2 deficiency.@*METHODS@#Clinical data of the child was retrospectively analyzed. Targeted capture-next generation sequencing and Sanger sequencing were carried out to detect potential variants.@*RESULTS@#The patient's main features included micropenis and hypospadia. He was found to harbor compound heterozygous c.680G>A (p.R227Q) and c.3G>T (p.M1I) variants of the SRD5A2 gene. Among these, c.680G>A (p.R227Q) was inherited from his father and was a known pathogenic mutation, while c.3G>T (p.M1I) was inherited from his mother and was unreported previously.@*CONCLUSION@#The compound heterozygous variants of the SRD5A2 gene probably underlay the disease in this child, who was eventually diagnosed with 5α-reductase 2 deficiency.

Clinical features and genetic testing of a Chinese pedigree affected with Smith-Lemli-Opitz syndrome / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical features and genetic variants of two patients from a pedigree affected with Smith-Lemli-Opitz syndrome and explore their genotype-phenotype correlation.@*METHODS@#Clinical data and family history of the pedigree were collected. Whole exome sequencing was carried out to identify the potential variants. Suspected variants were verified by Sanger sequencing of the family members.@*RESULTS@#The proband and her sister both presented with feeding difficulty, facial dysmorphism, seizures, and mental and speech retardation. The third child of this family presented with feeding difficulty, poor weight gain and severe malnutrition after birth. He had died of unknown cause at 6 months without genetic testing. The fourth child was a healthy boy. Genetic testing showed that both the proband and her sister have carried c.127G>T (p.Val43Phe) and c.820_825del (p.Asn274_Val275del) compound heterozygous variants of the DHCR7 gene (NM_001360.2), but the fourth child carried neither of the variants. The two variants were unreported in the literature and disease-related databases, and were not included in the 1000G and gnomAD databases. The c.820_825del variant may affect the sterol-sensitive region of the DHCR7 protein, which can lead to deletion of two amino acids at positions 247 and 275, causing truncation of the DHCR7 protein. It is speculated that this may affect the stability of protein's spatial conformation, thereby decrease the activity of the enzyme. The c.127G>T variant may affect the first transmembrane region of the protein, which is involved in the transmembrane transport of proteins. Multiple software predicted it to be harmful. Conservation analysis suggested that the three amino acids all locate in a highly conserved region of the protein. In consideration of the clinical phenotype, family history and result of genetic testing, we speculated that both patients had Smith-Lemli-Opitz syndrome due to variants of the DHCR7 gene.@*CONCLUSION@#This pedigree has enriched the phenotypic and genotypic data of Smith-Lemli-Opitz syndrome, which clarified the genetic etiology of the patients and provided a basis for genetic counseling of this pedigree.

Clinical phenotype and variantal analysis of a pedigree affected with hereditary coagulation factor V deficiency / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for a pedigree affected with coagulation factor V (FV) deficiency.@*METHODS@#Clinical data of the patient and his family members was analyzed. Targeted capture and next-generation sequencing (NGS) and Sanger sequencing were carried out to detect potential variant of the FV gene.@*RESULTS@#The patient presented with jaundice and prolonged prothrombin time (PT) and activated partial thromboplastic time (APTT). V factor activity measured only 0.1% of the normal level, though the patient had no sign of bleeding. A paternal heterozygous variant c.653T>C (p.F218S) and a maternal heterozygous variant c.3642_3643del (p.P1215Rfs*175) were identified in the FV gene of the patient. His elder brother was a heterozygous carrier of the c.653T>C (p.F218S) variant. c.653T>C(p.F218S) was a known pathogenic variant, while the c.3642_3643del (p.P1215Rfs*175) variant was unreported previously.@*CONCLUSION@#Mutations of the FV gene probably underlie the hereditary coagulation factor V deficiency in this patient. NGS combined with Sanger sequencing has detected potential variant with efficiency and provided a reliable basis for clinical and prenatal diagnosis for this family.

Genotype-phenotype analysis of a homozygous familial hypercholesterolemia pedigree / 中华儿科杂志

Objective@#To analyze the genetic characteristics of a five generations pedigree with homozygous familial hypercholesterolemia (HoFH).@*Methods@#Prospective study. Twenty family members included a proband diagnosed as familial hyperlipidemia at the cardiology Department of Xi′an Children′s Hospital in October 2018 were research object. Clinical data were collected. Genome DNAs were extracted. Whole exons sequencing was performed on the proband using target capture next generation sequencing. Candidate gene mutation sites identified by bioinformatics were verified by Sanger sequencing in the family members. The genotype-phenotype correlation of the pedigree was analyzed between heterozygous mutation carriers and non-carriers.@*Results@#The proband was a 7-years and 10-month-old boy. He was born with a roundgreen bean size yellow skin protuberance in the skin of the coccyx. Since the age of 3-4 years old, xanthoma-like lesions with a diameter of 0.5-1.5 cm gradually appeared in the skin of bilateral elbow joints, knee joints and Achilles tendon. The height, weight and intellectual development of the child were the same as those of normal children at the same age. No similar xanthoma-like lesion was found in the other family members. The proband′s total cholesterol (TC) reached 18.16-21.24 mmol/L, and his low density lipoproteincholesterol (LDL-C) was 14.08-15.51 mmol/L. Carotid ultrasonography showed diffuse sclerotic plaques in bilateral carotid and vertebral arteries, and color Doppler echocardiography revealed aortic valve thickening and calcification. Gene testing identified that the proband carried a homozygous mutation C. 418G>A (p. E140K) in LDLR gene inherited from his parents who had a consanguineous marriage and carried a heterozygous mutation of LDLR-E140K, respectively.The TC, LDL-C and apolipoproteinB (ApoB) of LDLR-E140K gene heterozygous carriers ((8.40±0.13), (6.79±0.01) and (1.95±0.05) mmol/L, respectively) were significantly higher than those of non-carriers ((4.59±0.28), (3.35±0.39) and (0.86±0.10) mmol/L, t=7.269, 4.595, 6.311, respectively, P<0.05).@*Conclusions@#LDLR-E140K gene homozygous mutation is first reported to be associated with most severe phenotype HoFH. The genotype-phenotype analysis of the pedigree shows that the clinical phenotype of the proband with homozygous mutation is the most serious, and all the heterozygous mutation carriers present with hypercholesterolemia phenotype. The investigation confirms that LDLR-E140K is the pathogenic variation of familial hyperlipidemia.