A mild phenotype associated with der(9)t(3;9) (p25;p23)

A female infant is described with hypoglycaemia, hypotonia, obesity of the trunk and thighs, and mild dysmorphic features. Growth parameters were consistently above the 90th centile. Chromosome analysis showed her to have a derived chromosome 9 inherited from a maternal t(3;9)(p25;p23) by adjacent I segregation. She had features in common with both the dup(3p) and del(9p) syndromes. There are few reports of this chromosome rearrangement and the features are milder than expected for the degree of imbalance, complicated in males by sex reversal. The repeated reports of macrosomia may suggest an overgrowth syndrome.