A deletion in CFL-2 gene associated with Severe Nemaline Myopathy with peculiar features

Abstract

Context: Nemaline myopathy (NM) is the most common congenital myopathy characterized by muscle weakness and presence of nemaline bodies (rods) in muscle biopsy. Phenotype ranges from neonatal death to normal lifespan. 13 genes have been reported. We describe a new variant in cofilin 2 gene (CFL2;OMIM*601443). Case report: A 5-year-old boy born severely hypotonic and unable to breathe, in need of mechanic ventilation. Healthy non-consanguineous parents. Physical examination: severe hypotonia with only extraocular motricity preserved and multiple contractures. Dysmorphic features were observed as brachycephaly, hypertelorism, pseudohypertrophy, macroglossia, premature pubic hair. Deep reflexes were absent. CK: 1010U/l. DHEA-S elevated. Muscular biopsy: Rods, cores and dystrophic pattern. Exome: homozygous deletion in exons 1 to 4 of CFL2 and partial deletion of the next gene Sorting nexin-6 (SNX6) in Chr14:34.563.122-34.714.639. Conclusion: 9 cases were described previously: Age onset was before 31 months. 4 presented respiratory distress at birth, 1 presented macroglossia, 2 contractures, 2 spinal deformities and 3 delayed motor milestones. Our patient presents an extent deletion in homozygosis not described before. A second deletion was found in SNX6, which is involved in protein trafficking and is expressed in different cells, as endocrine and cardiac. The early puberty and dimorphisms could be due to SNX6, though there is no previous disease caused by this gene. Among differential diagnosis of macroglossia, congenital myopathy caused by CFL2 should be considered.