Interstitial deletion of the proximal long arm of chromosome 4 associated with father‐child incompatibility within the Gc‐ system: Probable reduced gene dosage effect and partial piebald trait

Abstract

Gc‐system typing by isoelectric focusing polyacrylamide gel electrophoresis and quantitative assays were carried out on a patient with a karyotype of 46,XY,del(4)(q12q21.1) and on his parents with normal chromosomes. Although a father‐child incompatibility within the Gc‐system suggested that its locus is on segment 4q12‐13, the serum concentration of vitamin D binding protein in the patient and his father were only about half of that of his mother and control individuals. The possibility of interference of a silent allele in the child could not be excluded. Associated congenital partial leukodermia appeared to be an expression of a partial piebald trait.