Wolf-Hirschhorn Syndrome: distal microdeletion of chromosome 4 short arm Background: Wolf-Hirschhorn Syndrome is a genetic disease, in which the defect is a partial deletion involving the distal part of the short arm of chromosome 4. The clinical manifestations are craniofacial anomalies, delayed psychomotor development and neurological disorders. Objetive: Describe a clinical case of Wolf-Hirschhorn Syndrome, with specific description of craniofacial dysmorphological features. Case report: A female hypotonic infant with microcephaly and facial dysmorphism like "greek helmet": prominent glabela, ocular hypertelorism, epicanthal folds and marked broad-beaked nose, with pre and postnatal severe growth deficiency, mental retardation and seizures. Conclusions: The fluorescence in situ hybridization (FISH) karyotype revealed loss of genetic material at chromosome 4 short arm, with deletion in band 4p15 confirming the diagnosis. A case of probable de novo mutation with deletion of gene WHSC1 and other linked contiguous genes.