A 12-month-old female infant with developmental delay, growth retardation, and dysmorphic features including dolichocephaly, telecanthus, ptosis, flat nasal bridge, anteverted nares, high-arched palate, carp-shaped mouth, micro-retrognathia, and low-set and posteriorly rotated ears was found to have an interstitial deletion of chromosome 11 involving bands q14-q22. Immunoblot analysis of her fibroblasts revealed a normal amount of mitochondrial acetoacetyl-coenzyme A thiolase, of which gene locus has been assigned to chromosome 11q22.3-q23.1. This result suggested that the region around the boundary of 11q22.3-q23.1 was intact in this patient.