A\xa0gene\xa0is the\xa0basic\xa0physical and functional unit of heredity.\xa0Genes\xa0are made up of DNA. Some\xa0genes\xa0act as instructions to make molecules called proteins. Alleles are forms of the same\xa0gene\xa0with small differences in their sequence of DNA bases.Synucleins are abundant\xa0brain proteins\xa0whose physiological functions are only poorly understood. The human synuclein family consists of three members – α-synuclein, β-synuclein, and γ-synuclein – which range from 127 to 140 amino acids in length and are 55–62% identical in sequence, with a similar domain organization.\xa0Human\xa0brain\xa0development is created through continuing complex interactions of\xa0genetic\xa0and environmental influences. Twin studies in adults have found that many aspects of\xa0brain\xa0anatomy are highly heritable, demonstrating that\xa0genetic\xa0factors provide a significant contribution to variation in\xa0brain\xa0structures.