Doctors are baffled by a woman's mysterious respiratory problem. Featuring Cushing's syndrome, gout, carcinoid cancer.

A child with celiac disease is intolerant of gluten; a woman has her left frontal lobe removed to stop seizures; another woman suffers from fatigue and mood swings. Featuring celiac disease, mitral valve prolapse (MVP), epilepsy.

A child with Hurler's disease undergoes a stem-cell transplant procedure; a woman is diagnosed with myasthenia gravis; A father has seizures and fainting spells due to a heart arrhythmia. Featuring Hurler syndrome, myasthenia gravis, cardiac arrhythmia.

A young boy's body is not producing antibodies to fight infections; a cancerous tumor must be removed; a woman loses the ability to walk. Featuring common variable immunodeficiency (CVID), gastrointestinal stromal tumor (GIST), reflex sympathetic dystrophy (RSD).

A baby who cries and holds her cheek; a woman who gained 100 pounds in three months and developed severe acne; and an avid athlete struggling to catch his breath. Featuring trigeminal neuralgia, polycystic ovary syndrome and alpha-1 antitrypsin deficiency.

A 12-year-old girl experiences abdominal pains and severe headaches until she is diagnosed with a retroflexed odontoid and Chiari One malformation; a firefighter and paramedic is diagnosed with acquired immunodeficiency syndrome (AIDS).

A 5-year-old has a persistent fever and stomachache. A man crippled with a neck tilt. A woman falls ill after traveling abroad. Featuring Crohn's disease, cervical dystonia, brucellosis.

Two brothers suffer the same heart problem. Joanne suffers from joint pain, mouth ulcers, genital sores, skin lesions, and vision problems. Featuring Barth Syndrome, Behcet's Disease

A baby is irritable, has trouble nursing and stops gaining weight. When the infant begins suffering repeated seizures and eventually begins sustaining rapid-onset cerebral ischemia, they are diagnosed with moyamoya disease, and must be treated before they suffer lethal brain damage from the repeated ischemic incidents. A man initially diagnosed with hypoglycemia finds out he's got a tumor in his lung. A woman battling coughs, hives, and muscle weakness, was revealed to have an elevated eosinophil count.

A baby drinks excessively, projectile vomits and stops growing. A professional baseball player's wife struggles to get pregnant due to a brain tumor. An old man is robbed of his eyesight.

Parents deal with a son with sinus infections and unsteady feet; a woman gains weight and has oily skin, hair loss, body cramps and irritable bowel syndrome. A reverend has trouble sleeping.

A man has suffered from vertigo and ear infections since childhood. A 16-year-old girl has headaches and neck twitching, that led to preeclampsia. A girl has a serious heart condition and stops growing and gaining weight.

A baby's hair appears brittle, and she is slow in developing after a case of whooping cough. Following a tube-tie procedure, Jackie contracted a flesh-eating disease. A boy develops nosebleeds, a sign of something much more terrifying.

A baby shows signs of a genetic disorder. A college graduate developed bloating, decreased sex drive, and yellowing of the eyes. Since childhood, Scott has battled an array of symptoms—severe joint pain, strange rashes, and an inability to sweat. Could his symptoms be related to his kidneys?

Roman was a baby when his parents noticed his head always tilting to one side and his eyes rolling back into his head when he looked up. Could the cause be just one condition? Sharon was an active varsity diver but after a car accident, she developed an unquenchable thirst that would soon take over her life. Peggy lived a healthy and active lifestyle, until one day when the mother of two experienced coughing, joint pain, and swelling.

Nicky was a healthy five-year-old boy until terrifying symptoms landed him in the hospital, fighting for his life. Kristine was a super mom until crippling abdominal pains would change her life forever. Jackie was active until mysterious pains wracked her entire body, eventually becoming so bad that she had to drop out of school.

A baby boy suffers from the same symptoms that killed off male offspring on his mother's side of the family, Could doctors figure out what it is before it's too late? A man in his late thirties experiences a constant, painful burning sensation in his chest, making breathing difficult, but an initial trip to the ER reveals nothing. A woman lives with joint pain, redness in her eyes, and a blood test revealed an elevated anti-nuclear antibody.

A doctor makes an unexpected discovery when he operates on a young woman; doctors try to reach a diagnosis when a marathon runner experiences mysterious fatigue.

An infant shows diverse symptoms; an ER nurse gets a diagnosis of lymphoma, before another symptom reveals her true illness.

Doctors wonder why an apparently healthy baby fails to achieve its developmental goals; on the other hand, a woman who seemed to be in good health suddenly becomes ill.

A woman experiences chronic stomach pain and diarrhea attributed to irritable bowel syndrome; another faces extreme fatigue and night sweating while pregnant.

A baby boy could not keep any food down; an X-Ray revealed that he had been born with a diaphragmatic hernia. A woman who suffers from extreme fatigue has strange cravings for pickles; when her heart nearly stops, doctors try to find the cause of her problems.

A pregnant woman experiences stomach pains and headaches; another woman experiences eye inflammation and joint stiffness.

An abnormality on the ultrasound alarms parents expecting a baby; a biology teacher has a series of strange symptoms.

An aspiring actress awakens to an excruciating pain on the right side of her face; Bill experiences nausea and strange tingling in his legs; doctor visits and MRI tests show how these two different cases reveal paralysis.