CD40 is a surface glycoprotein, member of the nerve growth factor rece
ptor family, which is expressed on B cells and plays an important role
in their development, growth, and differentiation. Using chromosomal
in situ hybridization, we localized the CD40 gene to the long arm of c
hromosome 20, bands q12-q13.2. This localization correlates well with
the mapping of the murine CD40 gene to the distal region of chromosome
2, syntenic to the human 20q11-q13 region.