NO EVIDENCE OF LINKAGE FOR CLEFT-LIP WITH OR WITHOUT CLEFT-PALATE TO A MARKER NEAR THE TRANSFORMING GROWTH-FACTOR-ALPHA LOCUS IN 2 POPULATIONS

Nonsyndromic cleft lip with or without cleft palate is a common birth defect, affecting approximately 1 in 1,000 Caucasian newborns. Thirty- five multiplex families from the mid-Atlantic region of the United Sta tes and 22 families from central Mexico with a nonsyndromic form of cl eft lip with or without cleft palate were selected for a linkage analy sis. A tetranucleotide repeat marker (D2S443) located on the same yeas t artificial chromosome as the transforming growth factor alpha locus was tested for linkage to a putative susceptibility Mendelian locus un der varying levels of pentrance. No evidence for linkage between D2S44 3 and a susceptibility locus for cleft lip with or without cleft palat e was found. Insight is given to explain this outcome in spite of the statistically significant associations found by other investigators.