Mutations in the Alpha 1,2-Mannosidase Gene

Introduction Mentally retarded people (ID) are defined by the American Intellectual Development Disorders Association as "a great limitation in both intellectual functioning and adaptive behavior." [1] Previously, people thought that behavioral abnormalities such as intellectual disability are caused by the social or environmental environment in which the individual lives. [2] However, advances in gene analysis have shown that more and more behaviors are affected by our genes, even if not controlled.

Mutations in the SNCA gene are important in PD since the genetically encoded protein α-synuclein is the major component of Lewy bodies and accumulates in the brains of PD patients. Mutations in several genes including SNCA, LRRK2 and GBA have been found to be risk factors for "sporadic" (non familial) PD. Mutation of gene LRRK2 is the most common known cause of familial and sporadic PD and accounts for about 5% and 3% of sporadic cases in individuals with a family history of this disease. Mutation in GBA is the greatest genetic risk of developing Parkinson's disease

Tay-Sachs is a mutation from the HEXA gene on chromosome 15, which encodes the α subunit of the lysosomal enzyme β-N-acetylhexosaminidase A. By 2000, more than 100 different mutations have been identified in the human HEXA gene. These mutations include single base insertions and deletions, splicing mutations, missense mutations and other more complex patterns. Each of these mutations alters the protein product (ie the enzyme) of the gene, sometimes severely inhibiting its function. Recently, collective research and pedigree analysis showed how this mutation occurred and spread among small founder groups. Early investigations focused on some of these founders.