title: Isolated exon 8 deletion in type 1 spinal muscular atrophy with bilateral optic atrophy: unusual genetic mutation leading to unusual manifestation?
abstract: Proximal spinal muscular atrophy (SMA) or type 1 SMA is a fatal autosomal recessive disorder usually caused by homozygous deletion of exons 7 and 8 in the survivor motor neuron (SMN) gene. Additional deletion of the neuronal apotosis inhibitory protein (NAIP) gene exacerbates the clinical severity. Isolated exon 8 deletion has been reported in a single case series of SMA types 2 and 3 and never with SMA type 1. While extraocular muscles are typically spared, there are a few case reports documenting associated external ophthalmoplegia. Optic atrophy is a hitherto unreported association of SMA. We report a 10-month-old male infant with SMA type 1 with optic atrophy due to isolated deletion of exon 8 of the SMN gene with intact exon 7 and NAIP gene.
authors.affiliation: Department of Pediatrics, Maulana Azad Medical College and Lok Nayak Hospital, New Delhi, India.
authors.forename: D
authors.initials: D
authors.lastname: Maiti
authors.forename: M
authors.initials: M
authors.lastname: Bhattacharya
authors.forename: S
authors.initials: S
authors.lastname: Yadav
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D005091:Exons; D017353:Gene Deletion; D005808:Genes, Recessive; D006801:Humans; D007223:Infant; D008297:Male; D051616:Neuronal Apoptosis-Inhibitory Protein / Q000235:genetics*; D009896:Optic Atrophy / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D014897:Spinal Muscular Atrophies of Childhood / Q000235:genetics* / Q000473:pathology; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics*
chemical_list: D051616:Neuronal Apoptosis-Inhibitory Protein; D055533:Survival of Motor Neuron 1 Protein