Mulibrey nanism

Mulibrey nanism (also known as Mulibrey dwarfism or Perheentupa syndrome) is a rare autosomal recessive disorder characterized by severe growth restriction affecting multiple organ systems. The name 'Mulibrey' is an acronym derived from the organs primarily involved: muscle (MU), liver (LI), brain (BR), and eye (EY). The condition is caused by mutations in the TRIM37 gene located on chromosome 17q22-q23, which encodes a peroxisomal protein involved in intracellular protein trafficking. Key clinical features include severe prenatal and postnatal growth failure with proportionate short stature, a characteristic triangular face with a high and broad forehead, low nasal bridge, and a small chin. Patients frequently develop constrictive pericarditis, which is a hallmark complication and a major cause of morbidity and mortality. Hepatomegaly due to hepatic congestion is common, and yellowish dots in the ocular fundi are a distinctive ophthalmologic finding. Muscle hypotonia, a peculiar high-pitched voice, and fibrous dysplasia of long bones may also be present. Many affected females develop ovarian fibrothecomas, and there is an increased risk of Wilms tumor in childhood. There is no curative treatment for Mulibrey nanism. Management is supportive and multidisciplinary, focusing on monitoring and treating cardiac complications, including surgical pericardiectomy for constrictive pericarditis and management of heart failure. Growth hormone therapy has been attempted but generally shows limited efficacy. Regular surveillance for tumors, particularly Wilms tumor in children and ovarian tumors in females, is recommended. Cardiac transplantation may be considered in cases of severe cardiomyopathy. The condition is most prevalent in Finland due to a founder effect, though cases have been reported worldwide.

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