Arachnoid cysts (ACs) are congenital fluid-filled malformations that account for approximately 1% of all intracranial, space-occupying lesions in the central nervous system.1 Despite an estimated prevalence of 1.4%, little is known about the pathogenesis of these presumed developmental anomalies of the arachnoid.2 The coincidence of ACs in known mendelian cystic disorders, such as autosomal dominant polycystic kidney disease,3 along with rare clinical reports of familial AC occurrence,4,5 suggests a genetic basis for the disorder. However, no gene or chromosomal abnormalities have been detected in familial intracranial AC. We present a familial form of isolated intracranial AC showing an X-linked dominant inheritance pattern and characterized by the presence of large, bilateral, and symmetric middle fossa ACs (Figure 1) in 4 family members of a nuclear kindred (Figure 2).
Furey CG, Timberlake AT, Nelson-Williams C, Duran D, Li P, Jackson EM, Kahle KT. Xp22.2 Chromosomal Duplication in Familial Intracranial Arachnoid Cyst. JAMA Neurol. Published online October 10, 2017. doi:10.1001/jamaneurol.2017.3399