Cognitive impairment in children with 5q-associated spinal muscular atrophy type 1: two case reports and the review of the literature

Background: Spinal muscular atrophy (SMA) is an autosomal recessive inherited disease. It is caused by mutations in the survival motor neuron1 (SMN1) gene on chromosome 5. The degeneration of lower motor neurons is the main feature. Current research focuses on the motor, respiratory, and swallowing systems of SMA children, and there are few studies on cognitive impairment. These studies evaluate the cognitive function of all diagnosed 5q- SMA patients, but have not reported and studied 5q- SMA patients who have already developed cognitive impairment. This is the first report of cognitive impairment in 5q-SMA patients. Cases presentation: The two cases of SMA type 1 reported by us are homozygous mutations in exons 7 and 8 of 5q13 SMN1 gene. Cognitive impairment occurs in infancy. Two patients had severe motor dysfunction and speech impairment, and their communication was characterized by eye and head movements with scoliosis and joint contracture. Conclusions: : Cognitive dysfunction in SMA patients may be related to dyskinesia, onset age, education level, and the pathogenesis may be related to brain developmental disorders and SMN protein deficiency. Severe cognitive dysfunction may be a co-morbidity of SMA. Cognitive dysfunction in patients with muscle weakness and atrophy suggests that clinicians should not miss and misdiagnose SMA.