Project description:We measured expression profiles of skin fibroblasts harvested during lip cleft surgery of neonates (until 16 days after birth) and children (until 10 years after birth) and compared them to fibroblast isolated from adult skin of breast, scar, and face. We observed clear differences between the cleft and facial fibroblasts and the fibroblasts of breast, as the former originate from the neural crest. Further, we observed differences between adult face fibroblasts and children fibroblasts.
Project description:Genome-wide DNA methylation profilinf from 67 non syndromic cleft lip and palate samples and controls using whole-blood DNA and Illumina Infinium Human Methylation 450K Bead array, in which over 485000 CpGs sites were analysed per sample
Project description:Orofacial clefts are one of the most common birth defects, affecting 1-2 per 1000 births, and have a complex etiology. High-resolution array-based comparative genomic hybridization has increased the ability to detect copy number variants that can be causative for complex diseases such as cleft lip and/or palate. Utilizing this technique on 97 non-syndromic cleft lip and palate cases and 43 cases with cleft palate only, we identified a heterozygous deletion of Isthmin 1 in one affected case, as well as a deletion in a second case which removes putative 3' regulatory information. Isthmin 1 is a strong candidate for clefting as it is expressed in orofacial structures derived from the first branchial arch and is also in the same synexpression group as fibroblast growth factor 8 and sprouty RTK signaling antagonist 1a and 2, all of which have been associated with clefting. Copy number variants affecting Isthmin 1 are exceedingly rare in control populations, and Isthmin 1 scores as a likely haploinsufficiency locus. Confirming its role in craniofacial development, knockdown or CRISPR/Cas9-generated mutation of isthmin 1 in Xenopus laevis resulted in mild to severe craniofacial dysmorphologies, with several individuals presenting with median clefts. Moreover, knockdown of isthmin 1 produced decreased expression of LIM homeobox 8, itself a gene associated with clefting, in regions of the face that pattern the maxilla. Our study demonstrates a successful pipeline from copy number variant identification of a candidate gene to functional validation in a vertebrate model system and reveals Isthmin 1 as both a new human clefting locus as well as a key craniofacial patterning gene.
Project description:Cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex, heterogeneous etiology. It is well-established that both common and rare sequence variants contribute to the formation of CL/P, however, the contribution of copy number variants (CNVs) to cleft formation remains relatively understudied. To fill this knowledge gap, we conducted a large-scale comparative analysis of genome-wide CNV profiles of 869 individuals from the Philippines and 233 individuals of European ancestry with CL/P with three primary goals: first, to evaluate whether differences in CNV number, amount of genomic content, or amount of coding genomic content existed within clefting subtypes; second, to assess whether CNVs in our cohort overlapped with known Mendelian clefting loci; and third, to identify unestablished Mendelian clefting genes. Significant differences in CNVs across cleft types or in individuals with non-syndromic versus syndromic clefts were not observed, however, several CNVs in our cohort overlapped with known syndromic and non-syndromic Mendelian clefting loci. Moreover, employing a filtering strategy relying on population genetics data that rare variants are on the whole more deleterious than common variants, we identify several CNV-associated gene losses likely driving non-syndromic clefting phenotypes. By prioritizing genes deleted at a rare frequency across multiple individuals with clefts yet enriched in our case cohort compared to controls, we identify COBLL1, RIC1, and ARHGEF38 as clefting genes. CRISPR/Cas9 mutagenesis of these genes in Xenopus laevis and Danio rerio yielded craniofacial dysmorphologies, including clefts analogous to those seen in human clefting disorders.