A genetic study of vitamin D deficiency rickets: 2-sex differences and ABO typing.

In a further attempt to study the role of genetics in vitamin D deficiency rickets, 400 rachitic infants randomly chosen and aged from 6 months to 2 years (14.3 +/- 3.5 months) were investigated for sex differences and ABO typing. A significant (P < 0.001) predominance of the male sex was found, sex ratio being 1.43. Blood group A was significantly (P < 0.001) associated with rachitic patients whether males or females. Alkaline phosphatase values were significantly (P < 0.01) higher in male infants 91% of them had levels above 30 K.A. units, while the corresponding percentage of girls was 72%. This indicates that the disease is more severe among males. The study gives added support for the belief that there is a genetic factor in nutritional rickets.