Variable penetrance of hypogonadism in a sibship with Kallmann syndrome due to a deletion of the KAL gene

We report on the clinical and molecular characterization of 3 sibs with X‐linked ichthyosis and variable expression of Kallmann syndrome. One of the affected brothers had mild hyposmia and showed normal pubertal progression. However, we demonstrated the same partial deletion of the X‐linked Kallmann gene, sparing the first exon in the mildly affected patient as well as in one of his severely affected brothers. © 1995 Wiley‐Liss, Inc.