[Genetic analysis of a child with Complex cortical dysplasia with other brain malformations type 6 due to a p.M73V variant of TUBB gene].

OBJECTIVE: To explore the genetic basis for a child with multiple malformations. METHODS: A child who had presented at Shanxi Provincial Children's Hospital in February 2021 was selected as the study subject. Clinical data of the patient was collected, and whole exome sequencing (WES) was carried out to screen pathogenic variants associated with the phenotype. Candidate variant was validated by Sanger sequencing of her family members. RESULTS: The child had normal skin, but right ear defect, hemivertebral deformity, ventricular septal defect, arterial duct and patent foramen ovale, and separation of collecting system of the left kidney. Cranial MRI showed irregular enlargement of bilateral ventricles and widening of the distance between the cerebral cortex and temporal meninges. Genetic testing revealed that she has harbored a heterozygous variant of NM_178014.4: c.217A>G (p.Met73Val) in the TUBB gene, which was unreported previously and predicted to be likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). The child was diagnosed with Complex cortical dysplasia with other brain malformations 6 (CDCBM6). CONCLUSION: CDCBM is a rare and serious disease with great genetic heterogeneity, and CDCBM6 caused by mutations of the TUBB gene is even rarer. Above finding has enriched the variant and phenotypic spectrum of the TUBB gene, and provided important reference for summarizing the genotype-phenotype correlation of the CDCBM6.

Correlation of TGF-ß signaling pathway gene polymorphisms with unexplained recurrent spontaneous abortion.

BACKGROUND: The association of key genes in the transforming growth factor-ß (TGF-ß) signaling pathway and their gene polymorphisms with unexplained recurrent spontaneous abortion (URSA) is unclear. OBJECTIVE: To investigate the association of gene polymorphisms related to the TGF-ß signaling pathway in URSA women. METHODS: The study population consisted of 80 women with URSA and 90 normal control women, of which 10 women with URSA and 10 normal control women underwent high-throughput sequencing to select loci, and the remaining 70 women with URSA and 80 normal control women underwent flight mass spectrometry experiments to verify gene loci polymorphism. A total of 7 polymorphic loci in interleukin-6 (IL-6), TGF-ß1, TNF-α, SMAD1, and TNFRSF4 genes were screened by high-throughput sequencing combined with a review of databases. An SNP flight mass spectrometer (Mass ARRAY detection system) was applied to detect the polymorphisms and their frequencies in 70 women with URSA and 80 normal control women at the 7 gene loci. RESULTS: Among the 7 loci of IL-6, TGF-ß1, TNF-α, SMAD1, and TNFRSF4 genes, 2 loci were found to have significantly different allele and genotype frequency distributions between the 70 URSA and 80 normal controls, one was the IL-6 gene -174G/C locus (rs1800795), the risk of disease was 2.636 and 3.231 times higher in individuals carrying the C allele and CC genotype than in those carrying the G allele and GG genotype, respectively; the other was the TGF-ß1 gene -509T/C locus (rs1800469), and the risk of disease was 1.959 and 3.609 times higher in individuals carrying the T allele and TT genotype than in those carrying the C allele and CC genotype, respectively. The remaining 5 genetic loci have no statistically significant. CONCLUSION: IL-6 gene -174G/C locus (rs1800795) genotype CC and allele C may be the causative factor of URSA, TGF-ß1 gene -509T/C locus (rs1800469) genotype TT and allele T may be the causative factor of URSA, and polymorphisms of the 2 loci may be associated with URSA.

[Observation of spermatogenic cells for infertile patients with Y-chromosomal microdeletion].

OBJECTIVE: To assess the spermatogenic function of the infertile patients with Y-chromosomal microdeletion. METHODS: Thirty-five 23-44 years old patients with microdeletions of Y chromosome were included in this study. Three semen analyses confirmed that 26 cases were non-obstructive azoospermia and 9 oligospermia with sperm count < 1 x 10(6)/ml. They were divided into 3 groups by the locus of deletion, 5 cases of AZFa + b + c deletion in group 1, 4 cases of AZFb + c and 3 cases of AZFb deletion in group 2, and 23 cases of AZFc deletion in group 3. Semen was collected and centrifuged, the supernatant removed and the centrifugate applied on the clean slides after dilution. Following Wright's-Giemsa staining, the slides were viewed under the microscope. Testis histopathological biopsy was performed for 6 of the cases. RESULTS: In group 1, no spermatogenic cells were observed but only Sertoli cells in 1 case, with a consistency between the result of spermatogenic cell test and that of testis biopsy. In group 2, spermatogenic cell tests revealed spermatocytes in 6 cases, 2 were proved by testis biopsy with sperm maturation arrest in the primary spermatocyte stage, and spermatogenic cells of all developmental stages were seen in 1 AZFb deletion patient with the same sperm maturation arrest as the above two. In group 3, only primary spermatocytes were detected by spermatogenic cell test in 5 oligospermia patients but no spermatogenic cells in the 15 azoospermia cases, and biopsy revealed 2 cases of Sertoli cell-only syndrome. CONCLUSION: The spermatogenic cell test can effectively assess the spermatogenic function of AZF deletion patients. Non-invasive and easily accepted by patients, it is highly recommendable for the evaluation of spermatogenesis of patients with Y-chromosomal microdeletion.

Rapid molecular prenatal diagnosis of spondyloepiphyseal dysplasia congenita by PCR-SSP assay.

Heterozygous mutations of COL2A1 gene are responsible for type II collagenopathies. The common skeletal phenotypes include achondrogenesis type II, hypochondrogenesis, Stickler dysplasia, Kniest dysplasia, late onset spondyloepiphyseal dysplasia, and spondyloepiphyseal dysplasia congenita (SEDC). Prevention of SEDC can be achieved by prenatal diagnosis. This study reports the first rapid molecular prenatal diagnosis of SEDC performed in China by polymerase chain reaction sequence-specific primer (PCR-SSP) analysis. The pregnant woman we previously reported with SEDC carried the G to A substitution at nucleotide 1510 in exon 23 of COL2A1 gene, which caused a change from glycine to serine at codon 504 (G504S). By the time the woman got pregnant again, she had terminated two pregnancies and still had no child. In the first pregnancy, the molecular mutation of the family was not yet identified, and therefore prenatal diagnosis was unable to be performed by DNA analysis. In the second pregnancy, G504S mutation was found from fetal DNA. At the time of her third pregnancy, the woman and her husband became extremely worried about the potential SEDC for the fetus. For this reason, a quick and reliable molecular prenatal diagnosis of SEDC was performed by a PCR-SSP on an amniocyte sample collected at the 14th week of pregnancy. No mutation of the fetal DNA was identified. The result was obtained within 24 h after the sample was collected. The technique could be applied in confirmatory diagnosis and prenatal diagnosis for the affected family.

[Clinical, molecular and cytogenetic studies on 4 patients with 46, XX (SRY positive) male syndrome].

OBJECTIVE: To analyze the clinical, molecular and cytogenetic features of 46, XX (SRY positive) male syndrome. METHODS: The clinical features of 4 patients with 46, XX (SRY positive) male syndrome were analyzed retrospectively. Karyotyping, FISH, PCR amplification of the SRY gene, and Y-chromosome microdeletion were performed to study their molecular cytogenetic features. RESULTS: The Four patients were all sociopsychologically males of short stature and came to hospital for infertility. Physical examination revealed that their testes were small in volume and soft in texture, but their penes were normal. Semen analyses showed complete azoospermia. Detection of serum sexual hormone suggested hypergonadotropic hypogonadism. All were karyotyped as 46, XX. Molecular analyses revealed the presence of the SRY gene and absence of AZFa, b and c of the Y chromosome. FISH analysis showed that SRY genes were translocated to Xp in 3 of the patients. CONCLUSION: Phenotypically 46, XX (SRY positive) male patients are males generally, for the presence of the SRY gene in the whole genome and azoospermia due to the deletion of AZF. The clinical characteristics of the patient include testis dysgenesis, infertility and short stature. The long arm of the Y chromosome might contain the gene associated with body height. Extensive molecular and cytogenetic studies on 46, XX male syndrome may help to elucidate its genotype-phenotype relation.