Combination of cor triatriatum sinistrum and hypoplastic left heart syndrome in Meckel-Gruber syndrome: a case report.

Meckel-Gruber syndrome (MKS) is a fatal, autosomal recessive disorder characterized by malformation of central nervous system, particularly occipital encephalocele, bilateral renal dysplasia, and polydactyly. However, the clinical findings of this syndrome encompass various organ abnormalities as a result of genetic heterogeneity. The associated heart anomaly in MKS is inconstant. Its prevalence is rare and no striking or specific cardiac defects have been documented. We present a case of MKS with combined cor triatriatum sinistrum (left atrium divided into upper and lower compartment by a thin membrane) and hypoplastic left heart syndrome (underdeveloped mitral valve, left ventricle, and aorta) in a 33-week male fetus that was ultrasonographically detected and confirmed by autopsy. In addition to the cardiac defects, the patient was found to have postaxial polydactyly of 4 extremities, Dandy-Walker malformation, bilateral renal cystic dysplasia, and hepatic plate malformation. To the best of our knowledge, this is the first time that a combination of cor triatriatum sinistrum and hypoplastic left heart syndrome in MKS has been reported in the literature.