Kallmann syndrome is defined by the association of hypogonadotropic hypogon
adism and anosmia. The KAL1 gene is responsible for the X-linked form of Ka
llmann syndrome. We analyzed the KAL1 gene in 19 Japanese patients with Kal
lmann syndrome, including 3 patients reported previously, using PCR-direct
sequencing method. All of 19 patients were sporadic, except for 2 monozygot
ic twins. In this study, there were 3 kinds of mutations in the KAL1 gene.
One of them was a novel mutation consisting of a G to A substitution in the
acceptor site at the junction of intron 6/exon 7. None of the mutations ha
ve been reported in countries other than Japan. In male sporadic patients w
ith Kallmann syndrome, the incidence of mutations in Japanese patients (14%
: 2 of 14 cases) was slightly higher than that in patients in USA (8%). Als
o, we found 2 polymorphisms, which were always found together in 6 patients
The severity of hypogonadism was not related to the presence of mutations.
Unilateral renal aplasia and mirror movement, which are frequently found in
patients with the KAL1 gene mutation, were not related to the sites of mut