FRIDAY, Dec. 28 (HealthDay News) -- Though heart problems or heatstroke generally are to blame for a young athlete's sudden death, experts now know that carrying an aberration called the sickle cell trait also poses substantial risk.

FRIDAY Dec. 28 (HealthDay News) -- Both sickle cell disease and the condition known as sickle cell trait are genetic blood diseases: You're born with one or the other because of the genes inherited from your parents. Beyond that, the two conditions vary considerably.

FRIDAY, Dec. 28 (HealthDay News) -- Constant worriers are at increased risk for developing post-traumatic stress disorder (PTSD), according to a new study.

(HealthDay News) -- Carpal tunnel syndrome occurs when tissues adjoining tendons in the wrist swell and apply pressure to a nearby nerve, causing numbness and pain.

(HealthDay News) -- Morning sickness, characterized by nausea and vomiting during pregnancy, can cause malnutrition for the mother and the developing baby if it's severe enough.

FRIDAY, Dec. 28 (HealthDay News) -- With millions of Americans watching and waiting, the U.S. Supreme Court largely upheld the Obama Administration's health care reform legislation, making the survival of "Obamacare" this year's top health news story.

Here are some of the latest health and medical news developments, compiled by the editors of HealthDay: