Chondrocalcinosis is a common disorder which may associate with acute and chronic arthritis. A familial form, inherited as an autosomal dominant trait, has been mapped in a large family in which affected members also suffer recurrent fits in childhood. The gene which causes this disease shows linkage with several polymorphic markers on chromosome 5p with a maximum multipoint lod score of 4.6 between D5S810 and D5S416. Mapping a locus for chondrocalcinosis will allow the heterogeneity of the disorder to be assessed and may also be relevant to understanding the aetiology of osteoarthritis with which it commonly associates.