Similarly, biallelic truncating mutations in ERLIN2 cause infancy onset complicated HSP with lower limb predominant spastic tetraparesis, intellectual disability, pseudobulbar palsy and scoliosis (SPG18, MIM#611225 [https://www.omim.org/entry/611225])15–17 as well as primary lateral sclerosis18. This evidence concerns the gene ERLIN2 and pseudobulbar palsy.