A Heterogeneous Group of Disorders: Spinocerebellar Ataxias, Their Genetic Bases and Molecular Diagnoses

Scientific background: Spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative disorders that are inherited in an autosomal dominant manner. Population studies in certain geographical areas throughout the world indicate that the prevalence of SCA is 3/100 000. SCAs which are characterized by loss of balance and coordination, are progressive and late-onset disorders. Since the clinical symptoms of SCA subtypes significantly overlap, and since there is a high clinical variation even in each SCA subtype, the diagnosis of SCA patients, based on only clinical features, becomes difficult and complex. In this respect, the identification of the genetic etiology of SCAs is significant for understanding and classifying this group of disorders, and for definite diagnosis of patients. Today, molecular diagnosis of 12 autosomal dominant cerebellar ataxias with defined gene and mutations can be performed. The increase in the number of new ataxia genes suggests the guidance of well-defined clinical signs, neuropathological findings, family history, age of onset and population-specific SCA prevalence in molecular diagnosis. Conclusion: Although there has been no established therapy to prevent the progression of SCA yet, molecular analysis is required for the confirmation of cfinical diagnosis, the rough prediction of cfinical course and the family planning. Boðaziçi University experience reveals the importance of clinician-bench scientist cooperation and an intense dialogue for correct and definite SCA diagnosis.