Title: Novel GRHL3 Exonic/Intronic Variants in Puerto Ricans With Cleft Palate
Carolina Bello-Rivera (Presenter)
University of Puerto Rico
TAMARA BUSCH, University of Iowa
Ada Toraño, University of Puerto Rico
Natalio Debs, University of Puerto Rico
Maria Salcedo, University of Puerto Rico
Lydia López-Del Valle, University of Puerto Rico
Ricardo Ledesma, University of Puerto Rico
Mairim Soto-Ortiz, University of Puerto Rico
José Cordero, University of Puerto Rico
Mary Marazita, University of Pittsburgh
Azeez Butali, University of Iowa
Carmen Buxó-Martínez, University of Puerto Rico
Objectives: In Puerto Rico, the prevalence of cleft palate (CP) is 6.3 per 10,000 live births (2001-2013). Recently, a genome-wide association study reported a significant association of a missense variant in GRHL3 to non-syndromic cleft palate (nsCP). The study aimed to identify GRHL3 variants in Puerto Ricans with nsCP.
Methods: DNA samples from an ongoing case-control study (n=398) of Puerto Rican families were selected. Children (probands) with nsCL/P (n=199) ages 0-14 years were recruited as cases. DNA samples of nsCP probands (n=53) were selected for Sanger sequencing to study GRHL3 variants. We also sequenced the regions of variants in PAX7, ARHGAP29, IRF6, FOXE1, VAX1, BMP4, ADCY9, and MAFB. Findings were confirmed by reverse sequencing as well as sequencing the parents.
Results: Six missense mutations were identified. A novel G473V glycine to valine missense variant, located in exon 11, was found on proband and mother. Although predicted “tolerated” by SIFT and “benign” by PolyPhen, it may have a biological impact yet to be determined. Multiple sequence alignment (UniProtKB) showed the amino acid glycine to be conserved among the majority of the listed species. We also identified a novel 4bp heterozygous deletion mutation in exon 9 that replaces a cysteine with a stop codon, (Cys365Stop), causing a frameshift. This variant segregates in the family. A novel intronic single nucleotide polymorphism (SNP) (C/T) was identified on both proband and mother. Multiple sequence alignment (UCSC BLAT) showed it to be conserved in 8 out of the 9 species, suggesting it has evolutionary importance.
Conclusions: Our findings contribute to the limited knowledge about the etiology of nsCP and serve as potential risk factors to aid in genetic counseling, especially in this Hispanic population.