De novo interstitial duplication 4(q28.1q35) associated with choanal atresia.

We report a case of direct interstitial duplication of chromosome 4 from 4q28.1 to 4q35 associated with bilateral choanal atresia. The child also had dysmorphic features including a broad nasal bridge, telecanthus, downward slanting palpebral fissures, prominent ears, mild bilateral clinodactyly of the 5th fingers and bilateral hypoplasia of the 2nd-5th toenails. There was also a slightly dilated renal collecting system. At the age of 2.5 years, he had moderate global developmental delay, short, wide and tapering fingers, and short toes with hypoplastic toenails. To our knowledge, this is the second report of choanal atresia in a patient with trisomy 4q involving this region.