medwireNews: People with idiopathic REM sleep behavior disorder (iRBD) are more likely than those without the disorder to have a positive family history of dream enactment, an international team of researchers has found.
The results of the multicenter case-control study suggest that RBD may have a heritable component, say Yves Dauvilliers (Hôpital Gui de Chauliac, Montpellier, France) and co-authors writing in Neurology.
The study included 312 people with iRBD confirmed by polysomnography (PSG) and 315 RBD-free individuals matched for age and gender. These participants completed a questionnaire about their family history of neurologic, neurodegenerative, and sleep disorders.
Family medical histories were generally similar between iRBD patients and controls, with no difference in the frequencies of tremor, walking trouble, balance trouble, Parkinson's disease, memory loss, and Alzheimer's disease.
However, patients with iRBD were significantly more likely than control individuals to report a family history of dream enactment (13.8 vs 4.8%). This was true both for a family history in siblings (7.2 vs 1.9%) and in parents (7.2 vs 3.0%). Nearly three-quarters of affected relatives were male.
iRBD patients with and without a family history did not differ with regard to gender, age, ethnicity, or family history of other neurologic disorders.
Dauvilliers et al say their results confirm that RBD may have a familial component, with iRBD patients having a significantly higher frequency of positive family history for sleep disorders.
"Further studies are required to fully validate these findings using face-to-face clinical interview and video-PSG to test candidate genes and to perform linkage analysis or whole exome sequencing in the high segregated iRBD families," they conclude.
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