Vitamin A-enhanced cleft palate susceptibility associated with H-2.

Pregnant mice from the congenic strains C57BL/10Sn, B10.BR, B10.A/SgSn, B10.A(5R)/SgSn, B10.A(2R)SgSn and B10.A(18R)Sg were fed Purina Laboratory Chow or the same diet plus approximately 400 IU vitamin A daily and given 80 mg/kg dexamethasone intra-peritoneally or a sham injection on the 12th day of pregnancy. It was found that only strains with b alleles between H-2S and H-2D had significantly higher frequencies of isolated cleft palate among their progeny when fed the supplemental vitamin A. The locus appears to be on the centromeric side of a dexamethasone-induced cleft palate gene which has been mapped to the same general area.