Isolated Left Ventricular Noncompaction in a Case of Sotos Syndrome: A Casual or Causal Link?

A 16-year-old boy affected by Sotos syndrome was referred to our clinic for cardiac evaluation in order to play noncompetitive sport. Physical examination was negative for major cardiac abnormalities and rest electrocardiogram detected only minor repolarization anomalies. Transthoracic echocardiography showed left ventricular wall thickening and apical trabeculations with deep intertrabecular recesses, fulfilling criteria for isolated left ventricular noncompaction (ILVNC). Some sporadic forms of ILVNC are reported to be caused by a mutation on CSX gene, mapping on chromosome 5q35. To our knowledge, this is the first report of a patient affected simultaneously by Sotos syndrome and ILVNC. 1. Introduction Sotos syndrome [1] is an autosomal dominant condition, mainly occurring as a neomutation, characterized by a distinctive facial appearance, learning disability, and overgrowth resulting in tall stature and macrocephaly. This syndrome is known to be associated in 25% of cases with renal and cardiac abnormalities, such as patent ductus arteriosus, ventricular and/or atrial septal defects, seizures and/or scoliosis, and less frequently with a broad variety of additional features (hearing loss, abnormal vision, and thyroid disorders). In 2002, Sotos syndrome was shown to be caused by mutations and deletions of NSD1 gene, which encodes a histone methyltransferase involved in chromatin regulation mechanism. Furthermore, NSD1, mapping in 5q35 region, has multiple functional domains and may play different roles in regulating transcriptional processes, thus playing a negative or positive role according to cellular environment. In most of cases, abnormalities occurring in NSD1 gene are missense mutations in functional domains, partial deletions, and 5q35 variable-size microdeletions [2] encompassing it. We report a case of a patient with Sotos syndrome, who met echocardiographic criteria for ILVNC. 2. Case Report A 16-year-old boy affected by Sotos syndrome was referred to our outpatient cardiology clinic for fitness to noncompetitive sport. Diagnosis of Sotos syndrome had been established at birth and genetically confirmed. At physical examination, he presented with evident macrocephaly, height at the 96 percentile, normal psychomotoric development, and no hearing problems or thyroid disorders were detected. Rest electrocardiogram showed sinusal arrhythmia and an early repolarization pattern. Blood pressure was 120/70？mmHg, heart sounds were normal, no murmurs were present. The 2D echocardiogram demonstrated mild thickening of the left ventricular wall in the