Spinocerebellar ataxia type 12 (SCA12) (Spinocerebellar ataxia type 12) - PPP2R2B gene.

Spinocerebellar ataxia is a clinically and genetically heterogeneous group of disorders of the cerebellum group in which affected individuals show a progressive deterioration of locomotor coordination, dysarthria, and eye movements uncoordinated, because cerebellar degeneration with variable involvement of the brainstem and spinal cord.

Spinocerebellar ataxia type 12 (SCA12) is an autosomal dominant cerebellar ataxia (ADCA). This disease is due to mutations in the PPP2R2B gene, located on the long arm of chromosome 5 (5q32). This gene encodes a component that belongs to the family regulatory subunit B phosphatase 2. Protein phosphatase 2 is one of four major phosphatases Ser / Thr, and is involved in negative growth control and cell division. It consists of a heteromeric enzyme common base, consisting of a catalytic subunit and a regulatory subunit constant, which is associated with a variety of regulatory subunits. Regulatory subunit B could modulate substrate selectivity and catalytic activity. This gene encodes a beta isoform subfamily regulatory subunit B55.

Multiple variants have been identified alternatively spliced in this gene, encoding different isoforms. The 5'-UTR end of some of these variants includes a sequence of CAG trinucleotide repeat (7-28 copies) which can be expanded to 66 to 78 copies where SCA12.

This disease is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient for the disease to be expressed.  

Tests performed in IVAMI: in IVAMI perform detection of mutations associated with spinocerebellar ataxia type 12 (SCA12), by complete PCR amplification of the exons of the PPP2R2B gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).