erlin2 mutations in two iranian families with hereditary spastic paraplegia

spastic paraplegia 18 is an autosomal recessive disorder characterized by motor dysfunction, joint contracture and mental retardation. we describe two families as three cases. case 1 is a 35-year-old woman with and spasticity and mild weakness in lower limbs. case 2 and 3 are a sister and brother aged six and two respectively. the older sister suffered from lower limb spasticity, equinovarus and weakness in lower and upper hands. the brother had spasticity in lower limbs. parents of both families were consanguineous.  based on positive clinical findings hereditary spastic paraplegia (hsp) was suspected and targeted next generation sequencing was performed for genes responsible for hsp identifying a homozygote 37607361 ac>a mutation in erlin2.  in cases 2 and 3 a homozygous mutation was identified by whole exome sequencing. to date all patients, except one, reported with erlin2 mutations have intellectual disability.  our patient with normal intelligence, without additional findings highlights the fact that erlin2 mutations can present as uncomplicated hsp.