Three patients with terminal deletions within the subtelomeric region of chromosome 9q

We report on three male infants with de novo terminal deletions of chromosome 9q34.3. The clinical features are compared to the nine cases described in the literature. Case 1 and 3 were ascertained following the use of subtelomeric FISH to screen for a chromosomal anomaly, case 2 was confirmed by FISH probe following detection of a 9q deletion on standard karyotyping. Deletions in this region result in severe developmental delay, a distinct facial phenotype, cardiac anomalies, obesity, and respiratory failure, which may result in premature death. The delineation of the 9q deletion phenotype will aid diagnosis and genetic counseling as subtelomere FISH screening becomes more widely available.