Two siblings with marked dwarfism, now 11 and 19 years of age, have been followed from infancy. The girl had frequent episodes of pneumonitis and presented at age 4 years with hepatic enlargement and ascites which proved to be due to constrictive pericarditis. The boy presented with growth failure and pseudohydrocephalus. He had fibrous dysplasia of the tibia and a pathologic fracture; acute hepatic congestion followed physical activity at age 13 years and led to the diagnosis of constrictive pericarditis. Muscle function was normal, there was no evidence for a primary liver disorder, and mental development was normal so that the coined word "mulibray" seemed inappropriate. Pericardiectomy produced only partial improvement; both patients have hepatic enlargement and continue to need diuretics. A third patient with dwarfism, frequent respiratory infections, and pericardial calcification has certain features of the syndrome.