Unusual presentation of severe neonatal form of nemaline rod myopathy - ophthalmoplegia and ptosis

Abstract

We report a neonate who presented with floppiness after birth. She is the first baby girl of a non-consanguineous Chinese couple. There was decreased fetal movement detected in the third trimester. The delivery was uneventful with no need for resuscitation. No relevant family history could be elicited. After birth, she was found to have generalized hypotonia with minimal movement of the limbs. Multiple contractures were detected. All the muscles were wasted with no fasciculation. The jerks were absent. The face was myopathic with drooling of saliva. She had bilateral ptosis and complete ophthalmoplegia. Gag reflex was absent. Respiratory distress was noted. No organomegaly or cardiomyopathy was found. Her mother was noted to have mild myopathic face as well with no obvious muscle weakness or myotonia elicited. Preliminary investigations showed normal muscle enzyme with no acidosis. Electromyography showed myopathic changes. Muscle biopsy revealed nemaline rod myopathy. The baby’s developed recurrent aspiration pneumonia requiring ventilatory support. She had feeding difficulties and gastrostomy was performed for nutritional support. The child finally succumbed at the age of 6 months due to respiratory failure. This patient illustrated an unusual presentation of severe neonatal form nemaline rod myopathy with extraocular muscles involvement as these were usually spared. Clinically, the differential diagnoses were centroneuclear myopathy and congenital myotonic dystrophy since both involved extraocular muscles. Definitive diagnosis was made by muscle biopsy. Molecular studies were sent to Finland for further delineation of the underlying molecular defect. An accurate diagnosis is of ultimate importance for counseling on the child’s prognosis and the possibility of antenatal diagnosis in future pregnancies.