{Reference Type}: Case Reports {Title}: Retrocollis as the cardinal feature in a de novo ITRP1 variant. {Author}: Zachou A;Palaiologou D;Kanavakis E;Anagnostou E;Zachou A;Palaiologou D;Kanavakis E;Anagnostou E; {Journal}: Brain Dev {Volume}: 44 {Issue}: 5 {Year}: May 2022 {Factor}: 2.272 {DOI}: 10.1016/j.braindev.2022.01.005 {Abstract}: BACKGROUND: ITPR1 gene encodes inositol 1,4,5-trisphosphate-receptor-type 1, a Ca2+ channel highly expressed in cerebellar Purkinje cells. ITPR1 gene variants, through a loss-of-function mechanism, have been found to be related with the manifestation of spinocerebellar ataxia (SCA) 15, an adult-onset slow progressive cerebellar ataxia, SCA 29, a rare non-progressive congenital cerebellar ataxia and Gillepsie syndrome (SCA 29 phenotype plus aniridia). They share an heterogeneity of additional phenotypic features while no genotype-phenotype correlation has ever been found.
METHODS: Here we report the case of a boy with cerebellar ataxia who came to our clinic due to his cervical dystonia in the form of retrocollis. He presented an early-onset, non-progressive cerebellar ataxia, with cognitive impairment and delayed motor milestones. Whole exome sequencing (WES) revealed an heterozygous nucleotide variation, c.829A > C (p.Ser277Arg) in ITPR1 gene (NM_001168272.1), a de novo ITPR1 variant, as his parents came up with negative genetic testing. Due to his clinical presentation and genetic result, we came up with the diagnosis of SCA 29.
CONCLUSIONS: We described cervical dystonia as a phenotypic feature of ITPR1 related SCA 29, found in a new de novo ITPR1-variant.