Further Evidence for an Association Between Genetic Variation in Transforming Growth Factor Alpha and Cleft Lip and Palate To the Editor:

Ardinger et al. (1989) hypothesized that there might be a nonrandom association between clefting and RFLPs of candidate genes which have a role in palate formation. They reported a significant association be-tween two RFLPs of transforming growth-factor alpha (TGFa) and clefting in a group of 80 patients with nonsyndromic cleft lip with or without cleft palate (CLIP) and in a group of 102 controls (P =.0047 for the TaqI RFLP, and P =.0052 for the BamHI RFLP). However, in another study of seven families with CLI P segregating in a dominant manner, none of the TGFa haplotype associations reported by Ardinger et al. was seen, and, in one family, clefting did not cosegregate with TGFa, ruling out tight link-age in these families (Hecht et al. 1990). We have genotyped the TaqI RFLP in 96 unrelate