The case of a little girl has overturned the reputation of adult diseases with phenotypes linked to mutations in the HNRNPA1 gene (amyotrophic lateral sclerosis, hereditary myopathy with bordered vacuoles associated with Paget’s disease or distal myopathy with bordered vacuoles):
- between the ages of 3 and 5, she developed generalised muscle weakness and atrophy affecting the limbs and trunk, a myopathic facies, difficulty chewing and swallowing problems;
- at the age of 5.5, she lost her ability to walk and at 8, her ability to lift her arms;
- worsening bulbar problems led to a gastrostomy at the age of 9, and she died of a severe bacterial lung infection at the age of 11;
- muscle biopsy revealed significant muscle fibre atrophy, an increase in centralised nuclei, marked endomysial fibrosis, autophagic vacuoles and tubulofilament inclusions on electron microscopy;
- a detailed genetic analysis revealed a de novo deletion of 85 base pairs affecting exon 7 and intron 7 of the HNRNPA1 gene.
