Is NIPA1-associated hereditary spastic paraplegia always 'pure'? Further evidence of motor neurone disease and epilepsy as rare manifestations

Abstract

Pathogenic variants in the nonimprinted in Prader-Willi/Angelman syndrome (NIPA1) gene typically present with pure hereditary spastic paraplegia (HSP) but complex cases are described. We present a patient with childhood idiopathic generalised epilepsy (IGE) who later developed HSP. She rapidly deteriorated 27 years later with clinically definite amyotrophic lateral sclerosis (ALS). Her family history included HSP, IGE and motor neurone disease. Genetic testing identified a pathogenic variant in the NIPA1 gene associated with spastic paraplegia 6 (SPG6). This case provides the first description of NIPA1 in a family with epilepsy, ALS and thus complex HSP.