Alternative titles; symbols
Cytogenetic location: 22q11.2 Genomic coordinates (GRCh38): 22:17,400,001-25,500,000
Immunoglobulins (Ig) are the antigen recognition molecules of B cells. An Ig molecule is made up of 2 identical heavy chains (see 147100) and 2 identical light chains, either kappa (see 147200) or lambda, joined by disulfide bonds so that each heavy chain is linked to a light chain and the 2 heavy chains are linked together. The kappa and lambda light chains have no apparent functional differences. Each Ig lambda light chain has an N-terminal variable (V) region containing the antigen-binding site and a C-terminal constant (C) region, encoded by a C region gene (IGLC1; 147220), that provides signaling functions. The lambda light chain V region is encoded by 2 types of genes: V genes (see 147240) and joining (J) genes. Random selection of just 1 gene of each type to assemble a V region accounts for the great diversity of V regions among Ig molecules. The lambda light chain locus on chromosome 22 contains approximately 30 functional V genes, followed by approximately 4 functional J genes. Due to polymorphism, the numbers of functional V and J genes differ among individuals (Janeway et al., 2005).
The Ig lambda light chain J gene cluster is located within the Ig lambda light chain locus on chromosome 22q11.2 (Frippiat et al., 1995).
Frippiat, J.-P., Williams, S. C., Tomlinson, I. M., Cook, G. P., Cherif, D., Le Paslier, D., Collins, J. E., Dunham, I., Winter, G., Lefranc, M.-P. Organization of the human immunoglobulin lambda light-chain locus on chromosome 22q11.2. Hum. Molec. Genet. 4: 983-991, 1995. [PubMed: 7655473] [Full Text: https://doi.org/10.1093/hmg/4.6.983]
Janeway, C. A., Jr., Travers, P., Walport, M., Shlomchik, M. J. Immunobiology: The Immune System in Health and Disease. (6th ed.) New York: Garland Science Publishing (pub.) 2005. Pp. 103-106, and 135-139.