<prompt> All of the following are true about Frederichs ataxia exceptAutosomal recessiveSpinal cord, dorsal root ganglion cell are primarily involvedWeakness in lower limbsPlantar flexor response  <response>: Friedreichs ataxia is most common; autosomal recessive, onset before age 25; ataxia with areflexia, upgoing toes, vibration and position sense deficits, cardiomyopathy, hammer toes, scoliosis; linked to expanded trinucleotide repeat in the intron of gene encoding frataxin; a second form is associated with genetically determined vitamin E deficiency syndrome. Common dominantly inherited ataxias are spinocerebellar ataxia SCA1 olivopontocerebellar atrophy; ataxin-1 gene Fig. 184-1, SCA2 ataxin-2; pts from Cuba and India and SCA3 Machado-Joseph disease; all may manifest as ataxia with brainstem andor extrapyramidal signs; SCA3 may also have dystonia and amyotrophy; genes for each disorder contain unstable trinucleotide repeats in coding region. Symptoms may include the following: 91 of people develop hea problems such as cardiomegaly up to dilated cardiomyopathy, symmetrical hyperophy, hea murmurs, atrial fibrillation, tachycardia fast hea rate, hyperophic cardiomyopathy and conduction defects Cerebellar: nystagmus, fast saccadic eye movements, dysmetria, loss of coordination truncal ataxia and Stomping gait Vision impairment Hearing impairment Slurred speech Abnormal curvature of the spine Dorsal column: Loss of vibratory sensation and proprioceptive sensation occurs About 20 of people have trouble metabolizing carbohydrates and 10 develop diabetes mellitus Lower motor neuron lesion: absent deep tendon reflexes Pyramidal: extensor plantar responses, and distal weakness Muscle weakness in the arms and legs High plantar arches Ref Harrison20th edition pg 2765 