ALPHA-HEAVY CHAIN DISEASE - MOLECULAR ANA LYSIS OF A NEW CASE

The NH2-terminal structure of serum abnormal protein, as well as the s equence of the corresponding mRNA, were determined in a new case of al pha heavy chain disease. The patient presented with typical clinical f eatures of the disease. Intestinal and mesenteric lymphoplasmic infilt ration was monoclonal as assessed by the study of the configuration of heavy and light chain genes. The serum abnormal a chains included two molecular species: one starting at the beginning of the hinge region and the other being two aminoacids shorter, missing the two first amin oacids of the hinge region. The sequence of the mRNA displayed a leade r exon, a 93 bp sequence of unknown origin and the second and third co nstant exons of human alpha1 chain. These data are discussed in the li ght of previously reported molecular studies in heavy chain diseases.