Does someone know details about Lewy body dementia? Is it hereditary. Do other family members need checking?

Brain degeneration. The late life dementias are often characterized by the names of the proteins that accumulate. Lewy body dementia is also known as a synucleinopathy because the protein that builds up is called synuclein. When synuclein forms clumps, those clumps are called lewy bodies. There is no genetic test for lewy body disease. The cause is unknown. Lewy bodies in the brainstem cause parkinson's.
Rarely no test known. Neurodegenerative d/o featuring milder physical parkinsonism than parkinson's disease typically. (slowed movements, stiff/rigid muscles & posture, possibly resting tremor). But with early dementia, often with associated psychosis (visual hallucinations, delusional thoughts), excessive sleepiness, depression/anxiety/apathy, & rbd. Rbd = rem behavior d/o, causing acting-out of dreams in rem sleep.