Leukoencephalopathy in RIN2 syndrome: Novel mutation and expansion of clinical spectrum.

RIN2 syndrome also known as MACS syndrome is a rare autosomal recessive connective tissue disorder caused by RIN2 mutations and is accompanied by following clinical features: macrocephaly, coarsening of facial features, downward slanting palpebral fissures, Puffy droopy eyelids, full everted lips, soft redundant skin especially in face, gum hypertrophy, irregular dentition, sparse scalp hair, skeletal problems, joint hypermobility and scoliosis. RIN2 gene encodes the RAS and RAB interactor 2 and biallelic mutations in this gene cause cell trafficking dysfunction. Here we reported the eleventh patient of RIN2 syndrome in a 4 yr-old boy, from Tehran, Iran as the youngest reported patient so far. Whole exome sequencing revealed a novel frameshift homozygous variant of NM_001242581.1: c.2251dup; p.(Leu751Profs*9) in RIN2 gene. In addition to the previously reported symptoms for the RIN2 syndrome, white matter abnormalities in his brain MRI were noticed. Our findings expand the clinical spectrum of MACS syndrome due to mutation in RIN2 gene.