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A seven-year-old female presents with progressively worsening difficulty walking over the last six months. In the last few weeks, hand clumsiness and difficulty speaking clearly have appeared, prompting this visit. On examination, the patient's extensor plantar reflex is 2 + ; all others are 1 + 0. Which type of disorder is likely involved?

A. CAG trinucleotide repeat expansion disorder

B. CGG trinucleotide repeat expansion disorder

C. GAA trinucleotide repeat expansion disorder

D. GAC trinucleotide repeat expansion disorder

E. It is not a trinucleotide repeat expansion disorder

Answer with expl., please


i think it is c.

GAA repeat disorder..which is friedrich's ataxia..


correct, answer is c.
other trinucleotide repeat disorders are
Hintington d-se - CAG
Fragyle X - CGG
Miotonic dystrophy - CTG


Any disorder with GAC repeats????


huntington symptoms start at middle age. fragile x is only in male. what is speical of friedrich and myotonic dystrophy? thanks.


classical symptoms of myotonic dystophy, which include myotonia, muscle wasting, permature frontal balding, testicular atrophy, endocrine disturbances, neuropsychological deficits and cardiac conduction defects.


Can anyone explain to me how they knew the answer is freidrich's??Whats special about this disease that differentiates it from the other choices?


Who said Fagile X only occurs in male? It is X-linked dominant disease. So female can have it too, as long as one of her X chromosome is with the mutation.


Also...Bulbo-Spinal Muscular Atrophy (Kennedy's Syndrome); X-linked; CAG repeats


Friedreich's ataxia: gait ataxia, dysarthria, hand clumsiness, loss of sense of position, impaired vibratory sensation, loss of tendon reflex...



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