A slew of genes linked to brain disorders were among the highlights of another rich year in medical genetics:
Epilepsy and mental retardation: Usually, mutant genes on the X chromosome affect only men, because they, unlike women, don’t carry a second copy that can compensate. This past year researchers identified a mutant gene on the X that causes epilepsy and retardation only in women. Male carriers of the mutation are somehow spared its bad effects, but they pass on the disorder to their daughters.
Parkinson’s Disease: A mutant gene on chromosome 4 may give rise to some early-onset cases. The gene codes for the brain protein alpha-synuclein; a mutation is thought to produce misfolded proteins, which accumulate in the brain and may kill neurons that make dopamine. Loss of that neurotransmitter leads to tremors and muscle rigidity.
Boxer brain: Boxers with chronic brain injury—which has symptoms similar to Alzheimer’s and ...
