This familys heartbreaking struggle with dementia in midlife may upend our understanding of the disease and hope for a cure

Do the crossword every day.Exercise 150 minutes per week.

Follow the Mediterranean diet. While for most people these commandments of healthy living lower the risk of developing dementia with advancing age, in some individuals cognitive decline is unrelated to what they do, or fail to do.It is coded in their DNA, tied to a specific genetic mutation — and may well emerge during the prime of life no matter what healthy habits they adopt. In his new book, “The Vanishing Family: Love, Fate and the Quest to End Dementia,” Robert Kolker chronicles three generations of a family grappling with just such a cruel reality.

The author tells their dramatic story while also interweaving a broader one — how the medical understanding of dementia has progressed in fits and starts over the past 150 years and how, in the last decade, scientists have come to recognize that families like the one Kolker profiles may be key to finding a cure for all types of age-related brain impairment.The resulting book is an unlikely page-turner, a dual-track narrative by turns absorbing and wrenching, informative and inspiring.It’s a worthy follow-up to Kolker’s 2020 best-selling “Hidden Valley Road: Inside the Mind of an American Family,” about the descent into schizophrenia of six members of the Galvin family, and the genetic origins of that terrifying disease.In both books studying the science “was in the service of understanding the people, of walking in their footsteps,” Kolker told The Post.

Contacted four years ago by members of this family (their last name is not provided for privacy reasons) the author agreed to do a deep dive into their history just as he did with the Galvins’. Barb, 50, is the anchoring figure in “The Vanishing Family.” She was born the youngest of nine children of a prosperous couple, Ollie and Jean, who lived in the suburbs of Pittsburgh.Still at home when her much-older siblings had left, Barb witnessed first-hand the breakdown of her pare...