Theindex case wasa 5-year-old girlfromtheIndian state ofBihar, born to nonconsanguineous parents with a normal perinatal period. She waswell until 40 months ofage when she had an episode ofacute onset lethargy,and confusion following an upper respiratory tract infection andrecovered spontaneously overa period of 5 days. During therecovery phase, she had rapid involuntarymovements oftheeyes, tremulousmovementsand instability ofthe handsand fingers,and an unsteady gait. The unsteadiness of gait gradually reduced and shelearned to walkwithout falling. Over the next 3 months, she had two episodes offebrileillnessand atransient increasein unsteadiness during theseepisodes. At theage of 48 months, she had febrileencephalopathywith seizuresand was bed bound for 10 days. Shereturned to the baselineand was started onoral valproicacid. At 54 months ofage, she had slowly progressive hearing loss.
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