Nonsyndromic cleft lip and palate: no evidence of linkage to HLA or factor 13A.

Nonsyndromic cleft lip with or without cleft palate (CLP) is a common craniofacial anomaly, the etiology of which is not known. Population studies have shown that a large proportion of cases occur sporadically. Recently, segregation analyses applied to CLP families have demonstrated that an autosomal dominant/codominant gene(s) may cause clefting in cases. Associations of autosomal dominant CLP and nonsyndromic cleft palate (CP) with HLA and F13A genes on chromosome 6p have been suggested previously. Linkage to these two areas on chromosome 6p were tested in 12 autosomal dominant families with CLP. With a LOD score of -2 or less for exclusion, no evidence of linkage was found to four chromosome 6p markers. Multipoint analysis showed no evidence of a clefting locus in this region spanning 54 cM on chromosome 6p in these CLP families.