Monozygous twins discordant for amyotrophic lateral sclerosis.

A pair of identical female twins were discordant for amyotrophic lateral sclerosis. The affected twin was not breast-fed; was bitten by a poisonous snake, and was operated on for struma. She had more infections than her sister but no fractures. Her plasma insulin response to glucose loading was also higher. The twins lived separated in their early childhood.