Trisomy 9 mosaicism and XX sex reversal.

We report on a case of a phenotypic male infant who was referred to the genetics service due to dysmorphic features and congenital cardiac anomalies. Dysmorphic features included low-set, posteriorly rotated ears with squared, simple helices, midface hypoplasia, a broad nasal root with wide nasal alae, small mouth, micrognathia, short neck, overlapping fingers, rocker-bottom feet, prominent heels, and hypoplastic toenails. The phallus was normal and no testes were palpable in the scrotal sac. Cardiac anomalies included tricuspid atresia and a ventricular septal defect. The karyotype was 46,XX. Diagnostic microarray demonstrated evidence for trisomy 9 mosaicism, metaphase FISH revealed trisomy 9 on 7% of cultured cells, and interphase FISH analysis of a peripheral blood smear showed trisomy 9 in 78% of the cells examined. This is the first reported case of XX sex reversal in a patient with trisomy 9 mosaicism.