Intracranial aneurysms in polycystic kidney disease linked to chromosome 4.

Autosomal dominant polycystic kidney disease is genetically heterogenous, with at least two chromosomal loci accounting for the disease. When the mutation is located on chromosome 16 (PKD1), extra-renal manifestations such as the rupture of intracranial aneurysms are well known. In the case of localization on chromosome 4 (PKD2), in which the renal disease runs a milder course, not much is known about the incidence of extrarenal manifestations. A PKD2 family is reported in which two members had subarachnoidal bleeding due to intracranial aneurysms; there was strong clinical evidence of subarachnoidal bleeding in a third family member. This indicates that the familial clustering of intracranial aneurysms may also occur in PKD2 families. Because of the considerable mortality and morbidity of intracranial aneurysms, screening with magnetic resonance angiography in PKD2 patients with a positive family history of intracranial aneurysms is recommended.