Severe congenital nemaline myopathy with bilateral chylothorax caused by primary pulmonary lymphangiectasia

Abstract

Severe congenital nemaline myopathy is the most serious form of the diseases spectrum. The affected newborn has no spontaneous movement, fractures at birth and respiratory insufficiency. Nema-line myopathy is defined by the presence of nemaline rods in the sacroplasm. The present case was a Thai male floppy newborn with fractures of both humeri and femurs and ventilator-dependent respiration. The patient subsequently developed bilateral chy-lothorax two weeks later, and finally expired at the age of 6 weeks. Whole-body postmortem examination was performed upon inform consent. Muscle biopsy microscopically and ultrastructurally showed the features of nemaline myopathy. ACTA 1 heterozygous missense mutation (c.1127G>C) was identified. Microscopic examination of both lungs revealed marked dilataion of existing lymphatic vessels in the subpleural connective tissue, interlobular septa and peribronchovascular areas. Secondary events causing lymphatic dilatation were absent. The diagnosis of primary pulmonary lymphangiectasia was, therefore, firmly established. To the best of our knowledge, this is the first case of nemaline myopathy with primary pulmonary lymphangiectasia causing bilateral chylothrax. Only two cases of severe congenital nemaline myo-pathy with chylothorax were documented in the literature^1,2, and the etiology of chylothorax in those cases remained unclarified.