Genetic analysis of two children with developmental delay and intellectual disability / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology of two patients with developmental delay and intellectual disability.@*METHODS@#Two children who were respectively admitted to Henan Provincial People's Hospital on August 29, 2021 and August 5, 2019 were selected as the study subjects. Clinical data were collected, and array comparative genomic hybridization (aCGH) was carried out on the children and their parents for the detection of chromosomal microduplication/microdeletions.@*RESULTS@#Patient 1 was a 2-year-and-10-month female and patient 2 was a 3-year-old female. Both children had featured developmental delay, intellectual disability, and abnormal findings on cranial MRI. aCGH revealed that patient 1 has harbored arr[hg19] 6q14.2q15(84621837_90815662)×1, a 6.19 Mb deletion at 6q14.2q15, which encompassed ZNF292, the pathogenic gene for Autosomal dominant intellectual developmental disorder 64. Patient 2 has harbored arr[hg19] 22q13.31q13.33(46294326_51178264)×1, a 4.88 Mb deletion at 22q13.31q13.33 encompassing the SHANK3 gene, haploinsufficiency of which can lead to Phelan-McDermid syndrome. Both deletions were classified as pathogenic CNVs based on the guidelines of American College of Medical Genetics and Genomics (ACMG) and were not found in their parents.@*CONCLUSION@#The 6q14.2q15 deletion and 22q13-31q13.33 deletion probably underlay the developmental delay and intellectual disability in the two children, respectively. Haploinsufficiency of the ZNF292 gene may account for the key clinical features of the 6q14.2q15 deletion.

Prenatal genetic analysis of a fetus with Miller-Dieker syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for fetus with bilateral lateral ventriculomegaly.@*METHODS@#Fetus umbilical cord blood and peripheral blood samples of its parents were collected. The fetus was subjected to chromosomal karyotyping, whilst the fetus and its parents were subjected to array comparative genomic hybridization (aCGH). The candidate copy number variation (CNV) were verified by qPCR, Application goldeneye DNA identification system was used to confirm the parental relationship.@*RESULTS@#The fetus was found to have a normal karyotype. aCGH analysis indicated that it has carried a 1.16 Mb deletion at 17p13.3, which partially overlapped with the critical region of Miller-Dieker syndrome (MDS), in addition with a 1.33 Mb deletion at 17p12 region, which is associated with hereditary stress-susceptible peripheral neuropathy (HNPP). Its mother was also found to harbor the 1.33 Mb deletion at 17p12. qPCR analysis confirmed that the expression levels of genes from the 17p13.3 and 17p12 regions were about the half of that in the normal control, as well as the maternal peripheral blood sample. Parental relationship was confirmed between the fetus and its parents. Following genetic counseling, the parents has chosen to continue with the pregnancy.@*CONCLUSION@#The fetus was diagnosed with Miller-Dieker syndrome due to the de novo deletion at 17p13.3. Ventriculomegaly may be an important indicator for prenatal ultrasonography in fetuses with MDS.

Clinical and genetic analysis of two children with intellectual developmental disorder and microcephaly with pontine and cerebellar hypoplasia / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical features and genetic etiology of two children with intellectual developmental disorder and microcephaly with pontine and cerebellar hypoplasia (MICPCH).@*METHODS@#Two children with MICPCH who were presented at the Henan Provincial People's Hospital between April 2019 and December 2021 were selected as the study subjects. Clinical data of the two children were collected, along with peripheral venous blood samples of them and their parents, and amniotic fluid sample of the mother of child 1. Whole exome sequencing (WES), array-comparative genomic hybridization (aCGH) and real-time quantitative PCR (qPCR) were carried out for the children, their parents and the fetus. The pathogenicity of candidate variants were evaluated.@*RESULTS@#Child 1 was a 6-year-old girl featuring motor and language delay, whilst child 2 was a 4.5-year-old girl mainly featuring microcephaly and mental retardation. WES revealed that child 2 has harbored a 158.7 kb duplication in Xp11.4 (chrX: 41446160_41604854), which has encompassed exons 4~14 of the CASK gene. The same duplication was not found in either of her parents. aCGH revealed that child 1 has harbored a 29 kb deletion at Xp11.4 (chrX: 41637892_41666665), which encompassed exon 3 of the CASK gene. The same deletion was not found in either of her parents and the fetus. The above results were confirmed by qPCR assay. Above deletion and duplication were not found in the ExAC, 1000 Genomes and gnomAD databases. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were rated as likely pathogenic (PS2+PM2_Supporting).@*CONCLUSION@#The deletion of exon 3 and duplication of exons 4~14 of the CASK gene probably underlay the pathogenesis of MICPCH in these two children, respectively.

Clinical features and genetic analysis of two Chinese pedigrees affected with Joubert syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics and genetic basis of two Chinese pedigrees affected with Joubert syndrome.@*METHODS@#Clinical data of the two pedigrees was collected. Genomic DNA was extracted from peripheral blood samples and subjected to high-throughput sequencing. Candidate variants were verified by Sanger sequencing. Prenatal diagnosis was carried out for a high-risk fetus from pedigree 2.@*RESULTS@#The proband of pedigree 1 was a fetus at 23+5 weeks gestation, for which both ultrasound and MRI showed "cerebellar vermis malformation" and "molar tooth sign". No apparent abnormality was noted in the fetus after elected abortion. The fetus was found to harbor c.812+3G>T and c.1828G>C compound heterozygous variants of the INPP5E gene, which have been associated with Joubert syndrome type 1. The proband from pedigree 2 had growth retardation, mental deficiency, peculiar facial features, low muscle tone and postaxial polydactyly of right foot. MRI also revealed "cerebellar dysplasia" and "molar tooth sign". The proband was found to harbor c.485C>G and c.1878+1G>A compound heterozygous variants of the ARMC9 gene, which have been associated with Joubert syndrome type 30. Prenatal diagnosis found that the fetus only carried the c.485C>G variant. A healthy infant was born, and no anomalies was found during the follow-up.@*CONCLUSION@#The compound heterozygous variants of the INPP5E and ARMC9 genes probably underlay the disease in the two pedigrees. Above finding has expanded the spectrum of pathogenic variants underlying Joubert syndrome and provided a basis for genetic counseling and prenatal diagnosis.

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.

Genetic analysis of 21 fetuses with high suspicion of congenital skeletal malformation by prenatal ultrasound / 中华围产医学杂志

Objective:To explore the genetic etiology of fetuses with high suspicion of congenital skeletal malformation detected by prenatal ultrasound.Methods:This retrospective study collected 21 pregnant women with highly suspected fetal skeletal malformation indicated by ultrasound (the couples had no skeletal malformation) at Institute of Medical Genetics, Henan Provincial People's Hospital from January 2019 to August 2020. Amniotic fluid/umbilical cord blood of the fetus and peripheral blood of the couples were obtained for karyotype analysis, chromosomal microarray analysis, and whole-exome sequencing. Sanger sequencing was performed for the "pathogenic" "suspected pathogenic" "variants of uncertain significance" variants detected by whole exome sequencing. Genetic etiology of the 21 fetuses was described.Results:A total of five chromosomal abnormalities were detected, including four cases of trisomy 21 and one trisomy 18. Chromosome microarray analysis detected one case of abnormal copy number variation, 16 p11.2 microdeletion syndrome. Ten cases of monogenic diseases were found by whole exome sequencing and eight genes were involved ( SGMS2, FGFR3, DYNC2H1, WDR35, TBX5, COL2A1, FGFR2, and ALPL). Totally, 14 variations were detected, among which seven were novel variations (c.8129T>A, c.7126G>A, c.10307_10320del, and c.2641G>T in DYNC2H1 gene; c.3085G>A and c.491G>A in WDR35 gene; c.1070G>T in COL2A1 gene). Conclusions:For fetus, whose parents have no skeletal malformation, highly suspected of congenital malformation of skeletal system by prenatal ultrasound, genetic factor is the primary reason, including chromosomal abnormalities, copy number variations, and monogenic mutations.

Genetic analysis and prenatal diagnosis of a Chinese pedigree affected with Usher syndrome due to novel compound heterozygous variants of PCDH15 gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical features and genetic variant in a patient with Usher syndrome.@*METHODS@#Whole exome sequencing was carried out for the patient. Suspected variants were validated by Sanger sequencing of her parents and fetus.@*RESULTS@#The proband was found to harbor compound heterozygous variants c.17_18insA (p.Tyr6Ter*) and c.4095_4096insA (p.Arg1366Lys fs*38) of the PCDH15 gene (NM_033056), which were respectively inherited from her father and mother. The same variants were not detected in 100 healthy controls. Based on the guidelines of the American Society of Medical Genetics and Genomics, both variants were predicted to be pathogenic (PVS1+PM2+PP4). By prenatal diagnosis, her fetus was found to carry the c.4095_4096insA variant. After birth, the child has passed neonatal hearing screening test, and no abnormal auditory and visual function was found after the first year.@*CONCLUSION@#The compound heterozygous variants c.17_18insA (p.Tyr6Ter*) and c.4095_4096insA (p.Arg1366Lys fs*38) of the PCDH15 gene probably underlay the Usher syndrome is this proband.

Advance in Transcranial Direct Current Stimulation for Cognitive Impairment in Parkinson's Disease (review) / 中国康复理论与实践

@#Cognitive impairment is the most common non-motor symptom of Parkinson's disease (PD), which may associate with the disorders of transmitters, cortical atrophy, proteinosis, etc., and seriously influence the motor function, ability of daily life of the patients. Transcranial direct current stimulation (tDCS), which may adjust the cerebral excitability, regional blood flow, plasticity of synapses, etc., has been used for PD cognitive impairment.