Friedrich’s ataxia

Friedrich s ataxia, the most common of early-onset inherited ataxias/ accounts for about one half of all cases of hereditary ataxia reported in Europe and the USA. The gene, which has only five exons, codes for a small protein called frataxin, of 210 amino acids. The most common mutation is the expansion of a... 

Ataxia - total or partial inability to coordinate voluntary bodily movements, particularly muscular movements. Friedrich s ataxia, an autosomal recessive trait with a prevalence of about 2 per 100000, is a lethal disease, defined as neurological (affecting the nervous system), but most patients die from cardiomyopathy. 

A couple undergoes genetic counseling for consultation on the possibility that they may have a child with Friedrich s ataxia, an autosomal recessive neuromuscular disorder. The disorder has been diagnosed in the wife s sister, and they are concerned that she is a carrier. The incidence of the disorder in the population is 1 in 25,000 live births. 

What is the probability that this couple s first child will have Friedrich s ataxia ... 

A mixed group which is now thought to exclude Friedrich s ataxia modes of inheritance not all well established. 

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