Wolf-Hirschhorn syndrome (WHS) is a disorder that affects many parts of the body. The major features of this condition include specific craniofacial malformations, delayed growth and development, intellectual disability and seizures. Here, we report a case of WHS: a 27-month-old girl with a microdeletion at distal part of short arm of chromosome 4. She had striking clinical features of WHS and had an apparently normal karyotype. Array comparative genomic hybridization performed on the DNA extracted from peripheral blood revealed loss of 1.7 Mb at 4q16.3-q15.3. Taken together, this data suggests that a patient with strong clinical suspicion of chromosome abnormality and normal conventional karyotype analysis should be further evaluated by molecular cytogenetic techniques such as array comparative genomic hybridization (aCGH) or fluorescence in situ hybridization (FISH).