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Familial Occurrence of Idiopathic Intracranial Hypertension.

BACKGROUND
Idiopathic intracranial hypertension (IIH) is a disorder of unknown etiology. Its occurrence in the general population is 1/100,000, and 20/100,000 among overweight women of childbearing age. Familial occurrence is reportedly uncommon and not well-characterized.


OBJECTIVES
To describe a familial association with IIH.


METHODS
We conducted a retrospective chart review of all familial cases of IIH examined in the neuro-ophthalmology clinic of our medical center between January 2006 and June 2013.


RESULTS
Of a total of 520 patients with IIH, 15 had other family members with IIH (from seven different families). The family relation was a mother and daughter in two families, a brother and sister in four families, and an aunt and two first-degree cousins in the seventh family. Symptoms, course of disease, and risk factors were similar among the relatives of all seven families, except for the age at diagnosis, which was different in one family. All of the adult patients of six families were obese (body mass index 25-35 kg/m2), and all of the members of the other family were morbidly obese. There was no association between other systemic risk factors and IIH.


CONCLUSIONS
IIH occurrence within a family is more common than previously believed, and its incidence in families is more common than in the general population. The clinical course appears to be similar in family members. Our findings suggest a genetic predisposition. Further investigation of familial cases may yield useful information on the pathogenesis and genetic nature of this condition.