'Human Immunoglobulin Heavy Variable Genes', the fourth report of the 'IMGT Locus on Focus' section, comprises five tables entitled: (1) 'Number of human germline IGHV genes at 14q32.33 and potential repertoire'; (2) 'Human germline IGHV genes at 14q32.33'; (3) 'Human IGHV orphons on chromosome 15 (15q11.2)'; (4) 'Human IGHV orphons on chromosome 16 (16p11.2)', and (5) 'Human IGHV allele table'. These tables are available at the IMGT Marie-Paule page from IMGT, the international ImMunoGeneTics database (http://imgt.cnusc.fr:8104) created by Marie-Paule Lefranc, Université Montpellier II, CNRS, France.