You’ll Miss Me When I’m Gone by Rachel Lynn Solomon

Eighteen-year-old twins Adina and Tovah have little in common besides their ambitious nature. Viola prodigy Adina yearns to become a soloist where overachiever Tovah awaits her acceptance to Johns Hopkins, the first step on her path toward med school. But one thing could wreck their carefully planned futures: a genetic test for Huntington’s. It’s turned their Israeli mother into a near stranger and fractured the sisters’ own bond in ways they’ll never admit.

When the results come in, one twin tests negative for Huntington’s. The other tests positive.