FAMILIAL IDIOPATHIC INTRACRANIAL HYPERTENSION AND VARIEGATE PORPHYRIA- IS THERE ANY CONNECTION - REPORT OF 3 SISTERS

There are at least 12 previous reports of familial occurrence of idiop athic intracranial hypertension (IIH), suggesting the presence of a ge netic factor- The authors report two sisters With IIH and a third sist er with variegate porphyria (VP). A review of vp is presented. The mod e of inheritance of IIH Cannot be determined but may be autosomal domi nant with variable expressivity and reduced penetrance of the phenotyp e. vp, which is inherited in this manner, can give rise to virtually a ll kinds of neuropathy. In addition, the two disorders have other simi lar features. Thus, there were reasons to consider the possibility tha t IIH was a manifestation of vp. However, a detailed comparison Of IIH and vp showed the similarities to be incomplete and the differences p ronounced, and in the sisters with IIH biochemical tests for vp did no t support the hypothesis. The coincidence was probably fortuitous, but for definite conclusions, testing would have been required also in th e acute stage Of IIH. This was not possible because the sisters with I IH had been asymptomatic for a long time when vp was diagnosed in the third sister.