The syndrome of ring chromosome 12.

We have studied a 13 month-old girl with failure to thrive developmental delay, and dysmorphic features. At 13 months, the weight-age was 1 month, length-age was 3 months and head circumference was at the 3rd centile for 3 months. Physical findings were: Epicanthal folds, mildly cupped, apparently low-set ears, highly arched palate, short neck with low hairline, clinodactyly, and single crease of left 5th finger. The modal chromosome number was 46. Trypsin-G banding identified a ring chromosome 12; Karyotype was 46,XX,r(12)(p13q24).