Interstitial deletion of chromosome 8p23.1 has been reported in patients with congenital heart defects, including atrial and ventricular septal defects, pulmonary stenosis, and complex cyanotic heart defects. GATA4, a zinc-finger transcription factor gene, has been localized to this region. GATA4 interacts with additional transcription factors in the embryogenesis of the primitive heart tube. Mutations in GATA4 are thought to be responsible for the congenital heart defects reported in association with this chromosomal deletion, and several familial point mutations leading to amino acid substitutions have also been identified. Left ventricular noncompaction (LVNC) is a clinically heterogeneous disorder characterized by LV myocardial trabeculations and intertrabecular recesses that communicate with the LV cavity. Patients may be asymptomatic or may present with evidence of severely depressed LV systolic and diastolic function. The LV may be dilated or hypertrophied, and clinical expression may be undulating. Several genetic causes of LVNC have been reported, with variable modes of inheritance, including autosomal dominant and X-linked inheritance, but relatively few responsible genes have been identified. A 12-year-old boy with a history of acute lymphoblastic leukemia, dysmorphic features, and LVNC with preserved LV systolic function was referred to the Cardiovascular Genetics Clinic at our institution. The patient was asymptomatic in terms of cardiovascular function. Chromosome microarray testing revealed an interstitial deletion in the region of 8p23.1 containing GATA4. LVNC has not been reported previously in association with this chromosome deletion. Further investigation into the role of GATA4 in patients with LVNC is warranted. © 2011 Wiley-Liss, Inc.