G.P.236: Two siblings with SMARD1, one of them being in “double trouble”

The elder sibling, a boy, had tight heel cords that were noted from the age of 4months. He also developed varus foot position of the feet. At 20months, he could pull himself to standing. Lower leg muscles were atrophic, the ankles were unstable. He did not have a full extension of his fingers when he was crawling, and his pincer grasp was immature. Deep tendon reflexes could not be elicited. He had pectus excavatum. Cognitive function was normal. Neurophysiological investigation was suggestive of a polyneuropathy of axonal type and with predominantly motor affection, involving both lower and upper extremities. The MRI of cerebrum and medulla spinalis were normal. In the younger sister a syndromic evaluation was started in early infancy because of dysmorphic traits. She was hypotonic. At 9months she developed lung infection and atelectasis. She had increasing need for ventilatory support, and she got a tracheostomy. Attempts at weaning from the ventilator were unsuccessful. Additional findings were paradox diaphragm movement and neurophysiological signs of an axonal neuropathy. DNA was sent for the analysis of the IGHMBP2-gene, and she was diagnosed with SMARD1 with compound heterozygote mutations. At the same time, she tested postive for the Kabuki syndrome. Subsequent investigation in the brother disclosed the same mutations in the IGHMBP2-gene as his sister had. At the age 3.5years he can walk with ankle–foot orthoses, is not losing motor skills, and his ventilation is fo...
Source: Neuromuscular Disorders - Category: Neurology Authors: Source Type: research