Ring chromosome 15: expanding the phenotype.

Ring chromosome 15 is a rare disorder, with less than 50 cases reported in the literature to date. We report the clinical and cytogenetic evaluation of a patient with ring chromosome 15. Diagnostic tests including echocardiography, abdominal ultrasound, brain computerized tomography (CT), magnetic resonance imaging (MRI) and electroencephalogram (EEG) were done. Clinical examination of the patient revealed the characteristic features of ring chromosome 15, such as growth retardation, hypertelorism, frontal bossing, a highly arched palate, small hands and feet and café-au-lait spots. In addition, the patient presented with a mild intellectual disability, a congenital atrial septal heart defect, and abnormal EEG records. We also report 2 novel findings, which to our knowledge; have not been reported before in ring chromosome 15 patients: large areas of hyperpigmentation on the front of both legs and feet and hypogenesis of the corpus callosum. Cytogenetic studies using both conventional G-banding and fluorescence in situ hybridization (FISH) with a Sub Tel 15q probe confirmed the diagnosis of ring chromosome 15.