Hernias, Diaphragmatic, Congenital study with SNP Genotypes (NGS), WXS data on dbGaP (4 participants)

phs000485 — Gene Mutation and Rescue in Congenital Diaphragmatic Hernia

Congenital Diaphragmatic Hernia (CDH) is a common and life-threatening malformation. The most common phenotype is left-sided posterolateral (Bochdalek-type) hernia accompanied by pulmonary hypoplasia. Due to the high mortality, most of the cases have no family history for CDH. The rare presumed Mendelian instances of CDH have the potential to be extremely informative about the molecular mechanisms generating this phenotype. Three multiplex families were deemed meritorious for study by whole exome sequencing: <ol> <li>Parents who were 1st cousins gave birth to 2 children with CDH (one of whom also had cleft lip and palate), both now deceased. A DNA sample was available from one child. We proposed to perform a SNP array to identify regions of homozygosity by descent and intersect these regions with variants detected on exome sequencing. This effort has led to the identification of 3 confirmed variants. We are determining which if any are expressed in the primordial developing diaphragm and are also using bioinformatic approaches to determine which of these candidates interact with known CDH genes.</li> <li>This non-consanguineous couple gave birth to 2 affected boys with an identical and lethal CDH phenotype (consisting of diaphragmatic hernia, epigastric hernia, and facial dysmorphism) and one healthy boy. We predicted X-linked inheritance and findings from X chromosome microsatellite marker analysis are consistent with this. Accordingly, we are focusing on sequence variants mapping to the X chromosome. We have identified a single candidate gene and confirmed that the variant follows an X-linked pattern of inheritance in all family members. Expression studies are underway.</li> <li>These affected males are second cousins. By virtue of their position in the pedigree, we predicted an inheritance pattern consistent with X-linked inheritance. Data from WES and microsatellite marker analysis are currently being integrated.</li> </ol>