Loss of the Y chromosome PAR2 region and additional rearrangements in two familial cases of satellited Y chromosomes: cytogenetic and molecular analysis.

Two cases of rare structural aberrations of the Y chromosome were detected: a del(Y) (q12) chromosome in a child with mild dysmorphic features, obesity and psychomotor delay, and two identical satellited Y chromosomes (Yqs) in a normal twin, which were originally observed during routine prenatal diagnosis. In both cases a Yqs chromosome was detected in the father which had arisen from a reciprocal translocation involving the short arm of chromosome 15 and the heterochromatin of the long arm of the Y chromosome (Yqh). Cytogenetic and molecular studies demonstrated that in the reciprocal product of chromosomes 15 and Y PAR2 could not be detected, showing that PAR2 had been deleted.