SERPINA11 related novel serpinopathy - A perinatal lethal disorder.

SERPINA11 is a hitherto poorly characterised gene belonging to Clade A of the SERPIN superfamily, with unknown expression pattern and functional significance. We report a perinatal lethal phenotype in two foetuses from the same family associated with a biallelic loss of function variant in SERPINA11, and provide functional evidence to support its candidature as a Mendelian disorder. The SERPINA11 variant-associated foetal phenotype is characterised by gross and histopathological features of extracellular matrix disruption. Western blot and immunofluorescence analyses revealed SERPINA11 expression in multiple mouse tissues, with pronounced expression in the bronchiolar epithelium. We observed a significant decrease in SERPINA11 immunofluorescence in the affected foetal lung compared with a healthy gestation-matched foetus. Protein expression data from HEK293T cell lines following site-directed mutagenesis support the loss of function nature of the variant. Transcriptome analysis from the affected foetal liver indicated the possibility of reduced SERPINA11 transcript abundance. This novel serpinopathy appears to be a consequence of the loss of inhibition of serine proteases involved in extracellular matrix remodelling, revealing SERPINA11 as a protease inhibitor critical for embryonic development.

Fetal phenotypes of Mendelian disorders: A descriptive study from India.

OBJECTIVE: Exome sequencing (ES)-based diagnosis of Mendelian diseases in the fetus is limited by paucity of phenotypic information. This study reports the comprehensive phenotypes of some fetuses with Mendelian disorders. METHODS: Next generation technology-based sequencing of all coding regions of the genome (Exome sequencing) or targeted gene sequencing using Sanger or next generation platforms was performed in a cohort of deeply phenotyped, cytogenetically normal fetuses with morphological defects. Prenatal ultrasonographic phenotypes and postmortem details including dysmorphology, histopathology, and radiography were ascertained. Novel candidate genes, novel/unusual findings, and unusual genotypes in cases with confirmed Mendelian disorders are described. RESULTS: Of the 102 fetuses sequenced, 45 (44%) achieved definitive diagnosis of a Mendelian disorder with 50 pathogenic/likely pathogenic variants. The majority (87%) were autosomal recessive, 69% families were consanguineous, and 54% variants were novel. Dysmorphic syndromes, skeletal dysplasias, and metabolic disorders were the commonest disease categories, ciliopathies and dystroglycanopathies, commonest molecular categories. We describe the first fetal description of six monogenic diseases, and nine cases with novel histological findings. Nineteen cases had novel/unusual findings. CONCLUSION: This cohort demonstrates how deep fetal phenotypes of some Mendelian disorders can show novel/unusual findings, which have important implications for prenatal diagnosis of these conditions.

Fetal presentation of chondrodysplasia with joint dislocations, GPAPP type, caused by novel biallelic IMPAD1 variants.

Biallelic IMPAD1 pathogenic variants leads to deficiency of GPAPP (Golgi 3-prime phosphoadenosine 5-prime phosphate 3-prime phosphatase) protein and clinically causes chondrodysplasia, which is characterized by short stature with short limbs, craniofacial malformations, cleft palate, hand and foot anomalies, and various radiographic skeletal manifestations. Here we describe prenatal presentation of GPAPP deficiency caused by novel biallelic pathogenic variants, 2 base pair duplication in exon 2 of IMAPD1 gene in a patient of Asian-Indian origin. Further we report on diagnostic clues of prenatal presentation of GPAPP deficiency through ultrasonography, fetal MRI, and postmortem findings. We also provide evidence of pathophysiology of underlying GPAPP deficiency in the form of disorganization and dysplastic chondrocytes and reduced sulfation of glycoproteins through histopathology of cartilage similar to that described in mice IMPAD1 homozygous mutant model.

Exome sequencing for perinatal phenotypes: The significance of deep phenotyping.

OBJECTIVE: To ascertain the performance of exome sequencing (ES) technology for determining the etiological basis of abnormal perinatal phenotypes and to study the impact of comprehensive phenotyping on variant prioritization. METHODS: A carefully selected cohort of 32/204 fetuses with abnormal perinatal phenotypes following postmortem/postnatal deep phenotyping underwent ES to identify a causative variant for the fetal phenotype. A retrospective comparative analysis of the prenatal versus postmortem/postnatal phenotype-based variant prioritization was performed with aid of Phenolyzer software. A review of selected literature reports was done to examine the completeness of phenotypic information for cases in those reports and how it impacted the performance of fetal ES. RESULTS: In 18/32 (56%) fetuses, a pathogenic/likely pathogenic variant was identified. This included novel genotype-phenotype associations, expanded prenatal phenotypes of known Mendelian disorders and dual Mendelian diagnoses. The retrospective analysis revealed that the putative diagnostic variant could not be identified on basis of prenatal findings alone in 15/22 (68%) cases, indicating the importance of comprehensive postmortem/postnatal phenotype information. Literature review was supportive of these findings but could not be conclusive due to marked heterogeneity of involved studies. CONCLUSION: Comprehensive phenotyping is essential for improving diagnostic performance and facilitating identification of novel genotype-phenotype associations in perinatal cohorts undergoing ES.

Evaluation of in vitro sperm nuclear chromatin decondensation among different subgroups of infertile males in Mysore, India.

BACKGROUND: Infertility is a condition associated with multiple etiologies. Sperm nuclear chromatin decondensation is one of the important events that occur during fertilization. Abnormal spermatogenesis leads to improper protamine package and chromatin condensation. The aim of the study was to analyze and understand the levels of fertilization capacity and nuclear stability of the spermatozoa in different infertile subgroups. MATERIAL AND METHODS: A total of 65 infertile males and 24 fertile males were employed in the study. Infertile subjects were classified into different groups according to the World Health Organization (WHO) protocol. In this study, in vitro nuclear chromatin decondensation status was assessed in different subgroups of infertile males. The obtained data was then statistically analyzed. RESULTS: Decreased sperm chromatin decondensation was observed in different infertile subgroups compared to the control group (p < 0.05). Spermatozoa with swollen head indicated a positive response and unswollen head indicated a negative response. CONCLUSION: This study asserts that abnormal nuclear decondensation is a potential factor that diminishes the fertilizing capacity of the sperms among different subgroups of infertile males.