Neurogenetics

Neurogenetic diseases are an ever increasing, surprisingly common group of disorders. This chapter describes this group of disorders from the molecular DNA abnormality through to clinical manifestations. It outlines the factors that suggest a neurogenetic disorder, then modes of inheritance with examples of neurogenetic disorders in each of these groups, and finally the practical approach to neurogenetic diagnosis and genetic counselling. Advances in genetics have had an enormous impact on the field of the inherited neurological disorders, possibly more so than in other areas of medicine. The gene variants responsible for most autosomal recessive conditions are rare in the general population. Predictive genetic testing is often offered to individuals at risk, typically in the late-onset autosomal dominant inherited conditions. More common neurological diseases caused by mitochondrial point mutations include myoclonic epilepsy with ragged red fibres, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes and Leber’s hereditary optic neuropathy