<prompt> Pyramidal tract involvement with absent ankle jerk is seen in :Fredericks ataxiaSubacute combined degeneration of the spinal cordLathyrismTabes dorsalis  <response>: Answer is A Friedrichs ataxia: Absent deep tendon reflexes despite coicospinal tract involvement with an extensor plantar reflex is characteristic of Friedrichs ataxia. Pyramidal tract may be involved in Friedrichs ataxia or SACD amongst the options provided. Reflexes amongst these two conditions present the following picture Friedrichs ataxia SACD Deep tendon reflex are Increased deep tendons reflexes clonus characteristically absent Extensor planter Planter response is extensr Thus although both Friedrichs ataxia and SACD may present with absent ankle jerk, this feature is more characteristic and consistent with Friedrichs ataxia and hence this is the answer of choice. 