Prader–Willi syndrome and Tay–Sachs disease in association with mixed maternal uniparental isodisomy and heterodisomy 15 in a girl who also had isochromosome Xq

Malsegregation of chromosomes during reproduction can result in uniparental disomy when associated with trisomy rescue, monosomy rescue or gamete complementation. Pathogenicity stemming from uniparental disomy in liveborns results from imprinting disorders or autozygosity for autosomal recessive disorders. We report on a girl with Prader-Willi syndrome and Tay-Sachs disease resulting from maternal uniparental disomy of chromosome 15. The child …