Maternal uniparental disomy for chromosome 14 in a boy with a normal karyotype

Groningen, Ne report on a boy with a maternal uniparental disomy for chromo some 14 (UPD(14)). At 7 years of age he was referred to us by the paediatri cian because of symptoms of Prader-Willi syndrome (PWS). He showed short st ature, obesity, mild developmental delay, cryptorchidism, and some mild dys morphic features. The history further indicated intrauterine growth retarda tion at the end of the pregnancy. His mother was 44 years of age at the tim e of his birth. After birth he showed hypotonia with poor sucking, for whic h gavage feeding was needed. Motor development was delayed. After 1 year he became obese despite a normal appetite. Recurrent middle ear infections, a high pain threshold, and a great skill with jigsaw puzzles were reported. There were no behavioural problems or sleep disturbance. Chromosomal analys is was normal (46,XY). DNA analysis for Prader-Willi syndrome showed no abn ormalities. Two years later he was re-examined because we thought his featu res fitted the PWS-like phenotype associated with maternal UPD(14). At that time precocious puberty was evident. DNA analysis showed maternal heterodi somy for chromosome 14. In all the previously described 11 cases with mater nal UPD(I I), a Robertsonian translocation involving chromosome 14 was dete cted cytogenetically before DNA analysis. This is the first report of diagn osis of maternal UPD(14) based on clinical features. This finding underline s the importance of DNA analysis for maternal UPD(14) in patients with a si milar PWS-like phenotype even without previous identification of a Robertso nian translocation involving chromosome 14.