Analysis of a fetus with unbalanced translocation derived from a balanced t(6;14) maternal translocation / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic characteristics of a fetus with a high risk by maternal serum screening during the second trimester.@*METHODS@#Genetic counseling was provided to the pregnant woman on March 22, 2020 at Henan Provincial People's Hospital. G-banded chromosomal karyotyping and array comparative genomic hybridization (aCGH) were carried out on the amniotic fluid sample and peripheral blood samples from the couple.@*RESULTS@#The fetus and the pregnant woman were respectively found to have a 46,XX,der(6)t(6;14)(q27;q31.2) and 46,XX,t(6;14)(q27;q31.2) karyotype, whilst the husband was found to have a normal karyotype. aCGH analysis has identified a 6.64 Mb deletion at 6q26q27 and a 19.98 Mb duplication at 14q31.3q32.33 in the fetus, both of which were predicted to be pathogenic copy number variations. No copy number variation was found in the couple.@*CONCLUSION@#The unbalanced chromosome abnormalities in the fetus have probably derived from the balanced translocation carried by the pregnant woman. aCGH can help to determine the types of fetal chromosome abnormalities and site of chromosomal breakage, which may facilitate the prediction of fetal outcome and choice for subsequent pregnancies.

Copy number variation analysis and outcomes of 1 658 fetuses with increased nuchal translucency / 中华围产医学杂志

Objective:To analyze the genetic etiology and prognosis in fetuses with increased nuchal translucency (NT) in order to assist in the clinical prenatal genetic counseling and diagnosis.Methods:This study retrospectively enrolled 1 658 cases of singleton pregnancy (<35 years old) receiving invasive prenatal diagnosis, including karyotype analysis and/or chromosome microarray analysis or copy number variation (CNV) sequencing, due to NT value ≥2.5 mm in the first trimester in Henan Provincial People's Hospital from August 2014 to December 2021. They were divided into different groups according to the thickness of NT (≥2.5-<3.0, ≥3.0-<3.5, ≥3.5-<4.5, ≥4.5-<5.5, ≥5.5-<6.5 and ≥6.5 mm groups) and abnormal ultrasound findings (isolated increased NT group, increased NT complicated by soft markers/non-severe structural abnormality group and increased NT complicated by severe structural abnormality group). The results of invasive prenatal diagnosis and pregnancy outcomes were compared between different groups using Chi-square test and trend Chi-square test. Results:The detection rates of numerical abnormalities of chromosomes were 15.8% (262/1 658) and 17.6% (252/1 431) when the NT thickness cut-off value were 2.5 mm or 3.0 mm, respectively. Overall, the detection rate of numerical abnormalities of chromosomes increased with thickness of NT ( χ2trend=180.75, P<0.001), ranging from 6.6% (44/671) in the NT≥2.5-<3.5 mm group to 45.6% (113/248) in the NT≥5.5 mm group. The incidence of pathogenic/likely pathogenic CNV(P/LP CNV) did not increased with NT thickness ( χ2trend=3.26, P=0.071), and the highest detection rate was observed in the NT≥4.5-<5.5 mm group (9.0%, 19/211). The detection rate of numerical abnormalities of chromosomes plus P/LP CNV in the isolated NT≥2.5-<3.0 mm group and NT≥3.0-<3.5 mm group were 5.3% (10/188) and 9.6% (36/375), respectively, however, the difference was not statistically significant ( χ2=3.06, P=0.080). The detection rates of numerical abnormalities of chromosomes plus P/LP CNV in the isolated NT≥3.5-<4.5 mm group and NT≥2.5-<3.0 mm complicated by soft markers/ non-severe structural abnormality group were 12.7% (52/410) and 24.1% (7/29), respectively, and the risk were 2.6 times (95% CI: 1.3-5.2) and 5.7 times (95% CI: 2.0-16.4) of the isolated NT≥2.5-<3.0 mm group, respectively. The pregnancy termination rate increased with the NT thickness ( χ2trend=304.42, P<0.001), ranging from 10.8% (23/212) in the NT≥2.5-<3.0 mm group to 90.7% (117/129) in the NT≥6.5 mm group. After exclusion of the pregnancies terminated due to numerical abnormalities of chromosomes and P/LP CNV, 87.6% (862/984) of the fetus with increased NT were born alive. Conclusions:The detection rate of numerical abnormalities of chromosomes increases with the thickness of NT. Invasive prenatal diagnosis is required for non-advance aged singleton pregnant women when fetuses present with isolated NT≥2.5 mm with or without soft markers/structural abnormalities.

Pedigree analysis and prenatal diagnosis of intellectual disability caused by synonymous mutations of p.S434S in DLG3 gene / 中华围产医学杂志

Objective:To analyze the pathogenic gene and prenatal diagnosis of a family with intellectual disability.Methods:Out of this family consisting of 17 members in three generations, four males had intellectual disability. The proband's elder sister (Ⅱ-7) visited Henan Provincial People's Hospital in Oct 2019 for genetic counseling at 8 weeks of gestation. After informed consent was obtained, peripheral blood samples of the family members were collected. The whole exome sequencing was performed on the genome DNA of the proband (Ⅱ-9, male) and his parents to screen the candidate variants for phenotype co-segregated analysis by Sanger sequencing. The expression vectors were constructed by homologous recombination and the splicing experiments were performed in vitro. Reverse transcription polymerase chain reaction, Sanger sequencing, and TA clone sequencing were used to analyze the effect of candidate variants on splicing. After the pathogenic variant was determined the proband's elder sister underwent prenatal diagnosis (Ⅲ-7) using goldeneyeTM20A genotyping system and Sanger sequencing. Results:A hemizygous synonymous variant of c.1302G>A (p. S434S) in DLG3 gene was found in the proband by whole exome sequencing, which was carried by his mother (Ⅰ-1) and co-segregated with the phenotype in other family patients. In vitro splicing experiment showed that c.1302G>A variant led to abnormal splicing of 88.24% transcripts, which further resulted in the reading frame shift and protein function impairment. The mutation was not detected in the fetus (Ⅲ-7), who was born alive later and showed no abnormal mental or behavioral development at the age of one and a half year and is still being followed up. Conclusions:The synonymous mutation c.1302G>A in DLG3 gene was the etiopathogenesis of X-linked intellectual disability in this family.

Application of genomic copy number variation detection technology in prenatal diagnosis of 7617 pregnant women with serological screening abnormalities during the second trimester of pregnancy / 中华医学遗传学杂志

OBJECTIVE@#To analyze the genomic variation characteristics of fetal with abnormal serological screening, and to further explore the value of copy number variation (CNV) detection technology in prenatal diagnosis of fetal with abnormal serological screening.@*METHODS@#7617 singleton pregnant women who underwent amniocentesis for prenatal diagnosis solely due to abnormal Down's serological screening were selected. According to the results of serological screening, the patients were divided into high risk group, borderline risk group and single abnormal multiple of median (MOM) group. CMA and CNV-Seq were used to detect the copy number variation of amniotic fluid cell genomic DNA and combined with amniotic fluid cell karyotype analysis for prenatal diagnosis. Outpatient revisit combined with telephone inquiry was used for postnatal follow-up.@*RESULTS@#Among 7617 amniotic fluid samples, aneuploidy was detected in 138cases (1.81%) by CMA and CNV-Seq, 9 cases of aneuploid chimerism were detected by amniotic fluid cell karyotype analysis, and 203 cases of fetus carrying pathogenic and likely pathogenic CNV (P/LP CNV) were detected, the variant of uncertain significance (VUS) was detected in 437 cases (5.7%), the overall abnormal detection rate was 10.33%. The detection rate of aneuploidy by CMA and CNV-Seq in three group were 123 cases (2.9%), 13 cases (1.3%) and 2 cases (0.4%), respectively,and showing no significant difference (χ 2=7.469, P=0.024). The detection rate of pathogenic and likely pathogenic CNV in three group were 163cases (2.6%); 24 cases (2.6%) and 16 cases (3.3%), respectively, and showing no significant difference (χ 2=0.764, P=0.682). The CMA reported 2.9% (108/3729)P/LP CNV, and CNV-seq reported 2.4% (95/3888)P/LP CNV, both tests showed similar detective capabilities (χ 2=1.504, P=0.22).The most popular P/LP CNV in this cohort were Xp22.31 microdeletion, 16p13.11 microduplication /microdeletion, 22q11.21 microduplication /microdeletion. In fetuses with P/LP CNV CNV, 59 fetuses were terminated pregnancy, and 32 of 112 fetuses born had abnormal clinical manifestations. Non-medically necessary termination of pregnancy occurred in 11 fetuses carrying VUS CNV, 322 fetuses carrying VUS CNV were born, 4 of them presented abnormal clinical manifestations.@*CONCLUSION@#Compared with the traditional chromosome karyotype, CMA and CNV-Seq can improve the detection rate of pathogenic and likely pathogenic CNV. CMA and CNV-seq can be used for first tier diagnosis of pregnant women in the general population with abnormal Down's serological screening.

Genetic analysis and prenatal diagnosis of intellectual disability caused by Xq25 microduplication in a pedigree / 中华围产医学杂志

Objective:To analyze the clinical and genetic characteristics of a 27-year-old male patient with intellectual disability and his pedigree to provide a reference for genetic counseling and prenatal diagnosis.Methods:G-banding and array comparative genomic hybridization (aCGH) were performed to analyze the karyotypes and genomic copy number variations of the proband (Ⅲ-1) and his family members. Based on the results, prenatal diagnosis was performed for one pregnant woman (Ⅲ-2) in the pedigree who is the sister of the proband.Results:All karyotyping were normal in the family members, while aCGH results showed a 1 533 kb microduplication in the Xq25 region of the proband, his mother (Ⅱ-3), his uncle (Ⅱ-2), and his sister (Ⅲ-2), which was confirmed to be pathogenic. The proband and his uncle presented with intellectual disability, bradylalia, and facial dysmorphism. In contrast, his mother and sister showed normal phenotypes. His sister's fetal karyotype and aCGH results were normal, and the pregnancy continued. A male baby (Ⅳ-1) was delivered vaginally at term and showed no physical or intellectual abnormalities during a 46-month follow-up.Conclusions:Xq25 microduplication might be the cause of intellectual disability in the proband. STAG2 is probably the essential gene in Xq25 region.

Prenatal diagnosis and pregnancy outcomes of 17 fetuses with 16p13.11 microdeletion syndrome / 中华围产医学杂志

Objective:To investigate the association between prenatal genotype and phenotype of 16p13.11 microdeletion syndrome, aiming to provide a reference for prenatal diagnosis and genetic counseling.Methods:This retrospective study analyzed the results of comparative genomic hybridization microarray and low-coverage whole genome sequencing performed on 4 230 pregnant women in the Henan Provincial People's Hospital from July 2018 to July 2021. Indications for prenatal diagnosis, pedigree information and pregnancy outcomes of 17 fetuses with 16p13.11 microdeletion were described.Results:Prenatal diagnostic indications in the 17 fetuses were ultrasound abnormalities in five cases (increased nuchal translucency in four and cerebral ventriculomegaly with 10.7 mm in one), inter-twin weight discordance over 20% in one case, high risk in five cases and marginal risk in one in trisomy-21 serum screening, advanced maternal age in three cases (one with echogenic intracardiac focus in the left ventricle and two with normal ultrasound images) and adverse pregnancy history in two cases with normal ultrasound images. Pedigree verification that performed on 12 cases revealed that five were caused by de novo mutations and seven were inherited from their parents. The follow-up results showed that five cases were terminated, two lost to follow-up and 10 born alive (inheritance patterns were de novo mutations in three cases, parental inheritance in six and unknown pattern in one). These 10 infants were followed up from age 7 months to 3 years and 2 months and the results showed that one case was born with choroid plexus cyst of the left ventricle and presented instability of gait at 1 year and 3 months; one was a premature infant with 33 gestational weeks whose parents reported his language ability was not well at 2 years and 1 month old but without other abnormalities; one case had low muscle tone and was unable to keep head upright at 3 months who recovered at 5 months old after rehabilitation treatment according to the parents' report; all seven parents in the remaining seven cases reported no abnormalities. Conclusions:There was no specific prenatal diagnostic indication for 16p13.11 microdeletion syndrome. Genetic tracing, pregnancy outcome analysis and follow-up surveillance would provide reference for genetic counseling of 16p13.11 microdeletion syndrome.

Analysis of diagnosis and treatment of Lesch-Nyhan syndrome / 中华泌尿外科杂志

Objective:To explore the etiology, clinical diagnosis and treatment strategy of Lesch Nyhan syndrome.Methods:We retrospectively analyzed 2 patients with severe dyskinesia, mental retardation and complicated renal calculi who were admitted to the first people's Hospital of Zhengzhou in August 2019. Case 1, male, 9 years old, had multiple urinary calculi for 1 year. The patient came to the local hospital because double multiple kidney stones and bladder stonesa year ago. The patient had been treated with transurethral holmium laser lithotripsy for bladder stones. The results of infrared spectrum showed that the bladder stone was anhydrous uric acid stone. A week ago, color Doppler ultrasound showed multiple kidney stones and bladder stones. The patient was underdeveloped, mentally retarded and had a full-term cesarean section. There was no history of hypoxia, asphyxia and rescue of the patient. He had the following clinical manifestations: In the waking state, he was no language response to any stimulation. The nasolabial fold on the right was shallow and the corner of the mouth was oblique to the left. He lost the large movements such as lifting head, sitting alone, standing. The trunk showed torsion spasticity, limb muscle strength 2-3, limbs showing spastic hypertonia, limb joints stiff, hands showing fist-like, no involuntary movement and muscle fasciculation. The biceps reflex and knee tendon reflex were not elicited, and the pathological reflex was positive. Serum uric acid was 517 μmol/L. The Case 2 came from the same family, male, 6 years old, had the similar symptoms to his elder brother case 1. The family members complained on behalf of the child about intermittent fever for more than 2 years. The imaging examination of case 2 revealed kidney stones. Serum uric acid was 373 μmol/L. Whole Exome Sequencing and Sanger Sequencing were used to find the genetic causes of the two siblings. The NCBI-Homologene database was used to find the homologous sequence of the human HPRT1 gene, and the human HPRT1 gene sequence was compared with other species to analyze the protein conservation. The online website PredictProtein (http: //www.predactprotein) was used to predict the two-dimensional structure of the HPRT1 gene. The reported cases were summarized and same with the treatment plan.Results:A De novo mutation [c.571T>G(p.Tyr191Asp)] was found in the HPRT1 gene of the child, which was inherited from the mother. Lesch Nyhan syndrome can be diagnosed by the results of gene examination combined with clinical manifestations. The amino acid Tyr at the 191 position and the amino acids before and after it were highly conserved. Amino acid 191 was involved in the β-strand of the protein. We treated the patients with the lowest dose of allopurinol and children's conventional dose of potassium sodium bicitrate granules, and low purine diet. After 3 months of treatment, the serum uric acid was decreased, and the urinary calculi did not increase significantly.Conclusions:Combining with the clinical manifestations of children, HPRT1 gene might be the cause of pediatric disease and the two siblings could be diagnosed as Lesch-Nyhan syndrome. For such patients, the lowest dose of allopurinol and children's conventional dose of potassium sodium hydrogen citrate granule combined with diet could be more effective.

Identification of pathogenic variant in a Chinese pedigree affected with non-syndromic cleft lip and palate / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree affected with non-syndromic cleft lip and cleft palate (NSCLP).@*METHODS@#With informed consent obtained, members of the pedigree were subjected to clinical examination and history taking to exclude syndromic cleft lip and palate. One affected member was subjected to whole-exome sequencing and bioinformatics analysis. Candidate variant was verified by Sanger sequencing and co-segregation analysis of her family members and 100 unrelated healthy individuals.@*RESULTS@#Whole-exome sequencing and co-segregation analysis showed that all affected members of this pedigree have carried a heterozygous missense c.253A>G (p.Cys85Arg) variant in exon 4 of the IRF6 gene, which has co-segregated with the phenotype and was not found among the 100 unrelated healthy individuals.@*CONCLUSION@#The missense c.253A>G variant in exon 4 of the IRF6 gene probably underlay the NSCLP in this pedigree.

Hereditary spherocytosis due to a novel c. 5798+ 1G>A variant of the SPTB gene / 中华医学遗传学杂志

Objective@#To explore the genetic basis of a pedigree affected with hereditary spherocytosis.@*Methods@#Peripheral blood samples were collected from 17 members of the pedigree. Genomic DNA of the proband was subjected to next generation sequencing. Candidate variant was validated by co-segregation analysis. pCAS2c.5798+ 1G and pCAS2c.5798+ 1A plasmids were constructed by homologous recombination and transfected into 293T cells. Reverse transcription PCR, TA cloning and Sanger sequencing were used to analyze the effect of candidate variant on splicing. Meanwhile, peripheral blood RNAs were extracted to analyze the effect of candidate variant on splicing in vivo.@*Results@#The proband was found to carry a c. 5798+ 1G>A variant of the SPTB gene. The variant has co-segregated with the phenotype in the pedigree. In vitro and in vivo splicing experiments confirmed that the mutation has significantly affected the splicing, resulting in shift of reading frame and produced a premature termination codon.@*Conclusion@#The novel c. 5798+ 1G>A variant of the SPTB gene probably underlies the pathogenesis of hereditary spherocytosis in this pedigree.

Hereditary spherocytosis due to a novel c.5798+1G>A variant of the SPTB gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a pedigree affected with hereditary spherocytosis.@*METHODS@#Peripheral blood samples were collected from 17 members of the pedigree. Genomic DNA of the proband was subjected to next generation sequencing. Candidate variant was validated by co-segregation analysis. pCAS2(c.5798+1G) and pCAS2(c.5798+1A) plasmids were constructed by homologous recombination and transfected into 293T cells. Reverse transcription PCR, TA cloning and Sanger sequencing were used to analyze the effect of candidate variant on splicing. Meanwhile, peripheral blood RNAs were extracted to analyze the effect of candidate variant on splicing in vivo.@*RESULTS@#The proband was found to carry a c.5798+1G>A variant of the SPTB gene. The variant has co-segregated with the phenotype in the pedigree. In vitro and in vivo splicing experiments confirmed that the mutation has significantly affected the splicing, resulting in shift of reading frame and produced a premature termination codon.@*CONCLUSION@#The novel c.5798+1G>A variant of the SPTB gene probably underlies the pathogenesis of hereditary spherocytosis in this pedigree.

Genetic analysis of 90 families affected with spinal muscular atrophy / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for 90 families affected with spinal muscular atrophy (SMA), and discuss the necessity for carrier screening.@*METHODS@#All families were subjected to multiplex ligation-dependent probe amplification (MLPA) analysis. Combined MLPA and allele-specific PCR (AS-PCR) was used for prenatal diagnosis of the pregnant women.@*RESULTS@#Among the 90 couples, 84 (93%) had a negative family history, 85 (94%) had given birth to an affected child before. Eighty-five husbands and 88 wives carried heterozygous deletion of exon 7 of the SMN1 gene. Two wives had homozygous deletion of exon 7 of the SMN1 gene and were affected. Prenatal diagnosis showed that 19 fetuses were SMA patients, 48 fetuses were carriers, and 23 fetuses were normal. Of note, eighteen affected fetuses were conceived by couples without a family history, which accounted for 20% of all pregnancies and 95% of all affected fetuses.@*CONCLUSION@#To screen SMA carriers using MLPA and carry out prenatal diagnosis using combined MLPA and AS-PCR can ensure accurate diagnosis, which has a significant value for the prevention of SMA affected births.

Influence of uniparental disomy on the conclusion of paternity testing / 中华医学遗传学杂志

Objective@#To explore the influence of uniparental disomy (UPD) on bipartite and tripartite paternity testing.@*Methods@#Two cases of paternity testing were analyzed by multiplex amplification and capillary electrophoresis typing. Suspected UPD was verified by using single nucleotide polymorphism array (SNP array). Parental power index was calculated by using a bipartite or tripartite model.@*Results@#The two cases were found to harbor respectively three short tandem repeats on chromosome 2 and two short tandem repeats on chromosome 15. SNP array verified that both cases were of UPD. Case 1 had a parental power index of 122274987565.23 by a tripartite model, while case 2 had a parental power index of 13500.8463 by a bipartite model. Based on the technical specification, the conclusions supported a biological parent-child relationship in both cases.@*Conclusion@#UPD may lead to misjudgment of paternity testing. The possibility of UPD should be considered when certain loci which do not conform to Mendelian inheritance have aggregated to one chromosome.

Germinal mosaicism for partial deletion of the Dystrophin gene in a family affected with Duchenne muscular dystrophy / 中华医学遗传学杂志

Objective@#To carry out genetic testing and prenatal diagnosis for a family affected with Duchenne muscular dystrophy (DMD).@*Methods@#Multiplex ligation dependent probe amplification (MLPA) was used to detect potential deletion and duplication of the Dystrophin gene. Haplotype analysis was performed using five short tandem repeat polymorphism loci (3'-STR, 5'-STR, 45-STR, 49-STR, 50-STR of the DMD gene.@*Results@#A same deletional mutation (exons 51-55) of the DMD gene was detected in two brothers but not in their mother. The patients and fetus have inherited different haplotypes of the Dystrophin gene from their mother, suggesting that the fetus was unaffected.@*Conclusion@#The mother was very likely to harbor germline mosaicism for the Dystrophin gene variant. Genetic testing of peripheral blood samples cannot rule out germline mosaicism in the mother. Prenatal diagnosis should be provided for subsequent pregnancies in this family.

Prenatal diagnosis and genetic analysis of increased fetal nuchal translucency due to 2p15-16.1 microdeletion: a case report / 中华围产医学杂志

We reported the prenatal molecular diagnosis and pregnant outcome of a fetus with increased nuchal translucency.The ultrasound findings of the gravida at 12+5 gestational weeks indicated that the fetal nuchal translucency thickness was 4.5 mm,and non-invasive prenatal testing suggested as low risk.Amniocentesis was performed at 18 gestational weeks.Fetal chromosomal karyotype was normal but chromosome microarray comparative genomic hybridization analysis identified a 1.878 Mb deletion on chromosome 2p15-16.1.No copy number variation was found in the parents.The microdeletion was also verified by multiplex ligation-dependent probe amplification.Literature reported that chromosome 2p 15-16.1 microdeletion syndrome was characterized by mental retardation,language developmental disorder,microcephaly and so on.This case we reported here was a de novo 2p 15-16.1 microdeletion which contained the critical region and genes of 2p 15-16.1 microdeletion syndrome and was inferred to be a pathogenetic mutation.The gravida chose to terminate the pregnancy after genetic consultation.

Genetic diagnosis of a child with Smith-Magenis syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular mechanism of a girl with developmental delay and intellectual disability.@*METHODS@#Chromosomal karotypes of the child and her parents were analyzed with routine G-banding method. Their genomic DNA was also analyzed with array comparative genomic hybridization (aCGH) for chromosomal duplications/deletions.@*RESULTS@#No karyotypic abnormality was detected in the child and her parents, while aCGH has identified a de novo 3.37 Mb deletion at 17p11.2 in the child.@*CONCLUSION@#The child was diagnosed with Smith-Magenis syndrome, for which RAI1 may be the causative gene.

Analysis of ELN gene mutation in a pedigree affected with cutis laxa / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic diagnosis for a pedigree affected with cutis laxa.@*METHODS@#Genomic DNA was extracted from peripheral blood samples from members of the pedigree and 50 unrelated healthy controls. Potential mutation was screened by next-generation sequencing and verified by Sanger sequencing.@*RESULTS@#A heterozygous c.1985delG mutation was identified in the ELN gene among all patients from this pedigree. The same mutation was not found among unaffected family members and 50 healthy controls.@*CONCLUSION@#The genetic etiology for the pedigree has been elucidated, which has enabled genetic counseling and guidance for reproduction.

Prenatal diagnosis of partial trisomy 3q in a fetus / 中华医学遗传学杂志

OBJECTIVE@#To carry out prenatal diagnosis for a fetus with ultrasonographic abnormality.@*METHODS@#Chromosomal karyotyping and array comparative genomic hybridization (array-CGH) analysis were applied for the diagnosis. Peripheral blood samples were also taken from the parents for chromosome karyotyping analysis.@*RESULTS@#The fetal karyotype showed additional material of unknown-origin attached to Yq. Array CGH analysis confirmed that the material was derived from 3q22.1q29. The father was found to carry a balanced translocation 46, X, t(Y;3)(q12;q23) (which was diagnosed as 46,XY,Y≥18 elsewhere), whilst the mother was found to be normal.@*CONCLUSION@#3q partial trisomy may present as malformation of multiple systems. Combination of chromosome karyotyping and array-CGH can provide reliable diagnosis for fetuses with abnormalities by ultrasonography.

Influence of uniparental disomy on the conclusion of paternity testing / 中华医学遗传学杂志

OBJECTIVE@#To explore the influence of uniparental disomy (UPD) on bipartite and tripartite paternity testing.@*METHODS@#Two cases of paternity testing were analyzed by multiplex amplification and capillary electrophoresis typing. Suspected UPD was verified by using single nucleotide polymorphism array (SNP array). Parental power index was calculated by using a bipartite or tripartite model.@*RESULTS@#The two cases were found to harbor respectively three short tandem repeats on chromosome 2 and two short tandem repeats on chromosome 15. SNP array verified that both cases were of UPD. Case 1 had a parental power index of 122274987565.23 by a tripartite model, while case 2 had a parental power index of 13500.8463 by a bipartite model. Based on the technical specification, the conclusions supported a biological parent-child relationship in both cases.@*CONCLUSION@#UPD may lead to misjudgment of paternity testing. The possibility of UPD should be considered when certain loci which do not conform to Mendelian inheritance have aggregated to one chromosome.

Germinal mosaicism for partial deletion of the Dystrophin gene in a family affected with Duchenne muscular dystrophy / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for a family affected with Duchenne muscular dystrophy (DMD).@*METHODS@#Multiplex ligation dependent probe amplification (MLPA) was used to detect potential deletion and duplication of the Dystrophin gene. Haplotype analysis was performed using five short tandem repeat polymorphism loci (3'-STR, 5'-STR, 45-STR, 49-STR, 50-STR of the DMD gene.@*RESULTS@#A same deletional mutation (exons 51-55) of the DMD gene was detected in two brothers but not in their mother. The patients and fetus have inherited different haplotypes of the Dystrophin gene from their mother, suggesting that the fetus was unaffected.@*CONCLUSION@#The mother was very likely to harbor germline mosaicism for the Dystrophin gene variant. Genetic testing of peripheral blood samples cannot rule out germline mosaicism in the mother. Prenatal diagnosis should be provided for subsequent pregnancies in this family.

Genetic analysis of a pedigree affected with distal hereditary motor neuronopathy V / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing for a family affected with distal hereditary motor neuronopathy V (dHMN V).@*METHODS@#Potential mutations of the GARS and BSCL2 genes were analyzed with PCR and Sanger sequencing. Suspected mutation was verified among unaffected members of the family and 100 healthy controls. Prenatal diagnosis was provided based on the above results.@*RESULTS@#Sequencing analysis has identified a heterozygous c.269C>T (p.S90L) mutation in the BSCL2 gene, which resulted in replacement of Serine (TCG) to Leucine (TTG). The same mutation was found in all other 3 patients from the pedigree but not among unaffected members or the 100 healthy controls. By prenatal diagnosis, the fetus did not carry the above mutation.@*CONCLUSION@#Pathogenic mutation of BSCL2 gene probably underlies the dHMN V in this pedigree, which enabled prenatal diagnosis for the proband.