After moving houses, and months of strange behavior, 12-year-old Sammy stops walking and only hops; the doctors are the only hope to discover the cause of his bizarre symptoms. He is eventually diagnosed with PANDAS, a condition in which antibodies mistake his brain for Streptococcus bacteria.

Jessica is stricken with fevers and crippling migraines, and after Jake starts a military training program he finds hundreds of painful, fatty lumps appearing on his body.

A baby continuously gets bruises and spots all over her body, and even the smallest cuts cause her to lose shocking amounts of blood. Genetic tests reveal that the infant has the rare coagulopathy Glanzmann's thrombasthenia, a recessive genetic condition which prevents platelets from forming blood clots.

After suffering a series of debilitating incidents believed to be the result of Crohn's disease, Karen, an albino, has to have most of her colon removed. Several decades later, at the age of 38, she receives a phone call from someone who suggests she is suffering from a rare and fatal disease, Hermansky-Pudlak syndrome, which is also the cause of her albinism.

Lonnie's dreams of playing in the NFL are destroyed when boils develop on his head as a symptom of the painful skin condition hidradenitis suppurativa. Theresa suffers sight loss during her pregnancy; physicians struggle to find a diagnosis.

A three-year-old's unexplained vaginal bleeding sends her parents searching for answers to help their baby girl. Also, a student plagued by cramps is unable to hold her food down.

A mother rushes her toddler to hospital when she loses the ability to walk or stand. Plus, a runner tries to sleep off a numbness in his foot, but finds the sensation spreading.

When Jeanne fails to hit puberty, doctors discover that something truly bizarre is the cause; analysis of her DNA finds that she is genetically male, possessing Y chromosomes, but due to the rare genetic disorder Swyer syndrome, she appears outwardly female. Mary is stricken with a collapsed lung and breathing problems.

By the time Adrian is in high school his right leg weighs 150 lb (68 kg) and limits his mobility. Kathy is struggling to treat a rash and is experiencing weight loss. Can doctors help?