Utilization of Whole Exome Sequencing in Lethal Form of Multiple Pterygium Syndrome: Identification of Mutations in Embryonal Subunit of Acetylcholine Receptor.

The acetylcholine receptor (AChR) is a member of the superfamily of transmitter-gated ion channels having a critical role in controlling electrical signals between nerves and muscle cells. Disruptive mutations in genes encoding different subunits of AChR result in multiple pterygium syndrome (MPS), which can be associated with a severe prenatally lethal presentation. This study aimed to investigate the etiology of lethal MPS (LMPS) in two consanguineous families with a history of miscarriages. DNA was extracted from a tissue sample of two aborted fetuses (probands) from two different families with a history of spontaneous miscarriages. Parental peripheral blood samples were collected for confirmatory analysis and follow-up testing. Whole-exome sequencing (WES) was performed on DNA from the probands. The results were confirmed and segregated by Sanger sequencing. Moreover, protein structure evaluations were accomplished. We identified a homozygous frameshift mutation of c.753_754delCT (p.V253fs*44) and a homozygous missense mutation of c.715C>T (p.Arg239Cys) in the CHRNG gene. Both aborted fetuses had pterygium, severe arthrogryposis, and fetal hydrops with cystic hygroma, being compatible with LMPS. The heterozygous state was confirmed in parents for both CHRNG variants. Likewise, CHRNG mutation was predicted to display the damaging effects by lowering the number of helixes and modifying the surface electrostatic potential. The present study identified rare sequence variants in the CHRNG gene in aborted fetuses from consanguineous couples with recurrent miscarriage history. WES is a comprehensive and cost-effective approach to study heterogeneous diseases including MPS. Such findings can improve our knowledge of MPS databases, particularly for genetic counseling of high-risk families and preimplantation genetic diagnosis.

Frequency of TNFR1 36 A/G gene polymorphism in azoospermic infertile men: A case-control study.

BACKGROUND: Tumor necrosis factor-alpha (TNF-α) is a multifunctional cytokine that regulates different cellular activities related to spermatogenesis. Tumor necrosis factor-alpha receptor 1 (TNFR1) mediates TNF-α activity and polymorphism in TNFR1 could lead to gene dysfunction and male infertility. OBJECTIVE: The aim of this study is to determine the association of TNFR1 36 A/G polymorphism with the idiopathic azoospermia in Iranian population. MATERIALS AND METHODS: This case-control study included 108 azoospermic and 119 fertile men. This research investigated the frequency of TNFR1 36 A/G polymorphism in cases who were idiopathic azoospermic men referred to Yazd Research and Clinical Center for Infertility, Iran in comparison with controls. polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method was used to investigate the polymorphism in both case and control groups. PCR fragments were digested by Mspa1I enzyme and products were appeared by gel electrophoresis. The abundance of A→G was calculated in the azoospermic and healthy men. RESULTS: According to the present study, GG and AG genotypes frequency in the azoospermic men group were higher than the control group (OR= 2.298 (1.248-4.229), p=0.007), (OR=1.47 (0.869-2.498, p=0.149). Our findings also showed that G allele frequency in azoospermic men had significant difference compared to the control group (OR=2.302 (1.580-3.355), p<0.001). CONCLUSION: It seems that the GG genotype and G allele have an association with increased risk of non-obstructive azoospermia.