Kallmann's syndrome (KS) refers to the association of hypogonadic hypogonadism and anosmia or hyposmia. The X-linked form of the disease is due to mutations in the KAL1 gene that encodes for the protein anosmin-1. We studied the KAL1 gene in a patient with KS and his family by PCR amplification and direct sequencing. A novel missense mutation (V263G) that modifies the major cell adhesion site of the anosmin-1 protein was identified. Our results suggest that this reported mutation is responsible for KS and might help to elucidate the function of an important area of the anosmin-1 protein.

A functionally defective lambda 3-immunoglobulin chain gene has been cloned from plasmacytoma HOPC-1 (gamma 2b, lambda 1). The lambda 3 gene resulted from the juxtaposition of the germline V lambda 1 sequence with a J lambda 3 C lambda 3 gene segment. DNA sequencing of the rearranged V lambda 1 J lambda 3 exon showed the presence of a single base pair deletion at the site of V-J joining. The alteration in the reading frame caused by this deletion generated a stop codon at the 3' end of J lambda 3, thus rendering this gene nonfunctional for light chain production. In addition, a one-point mutation in the J lambda 3-C lambda 3 intron distinguishes the rearranged gene from the unrearranged counterpart. The implications that this rearrangement has in terms of the mechanism of somatic mutations and of selective proliferation of B cells mediated by antigen stimulation are discussed.

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