Comprehensive microsatellite marker analysis contradicts previous report of segmental maternal heterodisomy of chromosome 14.

Uniparental disomy of chromosome 14 (UPD(14)) results in one of two distinct abnormal phenotypes depending upon the parent of origin. The discordance between the maternal and paternal UPD(14) phenotypes may result from overexpression and/or underexpression of one or more imprinted genes located on chromosome 14q. A cluster of imprinted genes has been identified and localised to 14q32. However, it is unknown whether the altered expression of these genes results in any of the phenotypic features associated with maternal and paternal UPD(14). To refine the candidate imprinted region, it would be useful to identify cases of segmental UPD with clinical features associated with paternal or maternal UPD(14). We recently reported the first case of segmental paternal isodisomy of chromosome 14. In addition, there are two reported cases of segmental maternal UPD(14). 8 We recently had the opportunity to re-evaluate the patient reported by Martin et al.