Caused by gene changes, these disorders affect the body's ability to change food into energy. They also affect how energy is used, such as for cell repair.
Disease
Insomnia
This disorder can make it hard to fall asleep, hard to stay asleep or both, even though you have the chance for enough sleep. It can drain your energy.
Disease
Intermittent explosive disorder
This mental health condition involves sudden bouts of impulsive, aggressive, violent behavior or verbal outbursts that cause major distress in life.
Disease
Interstitial cystitis
Bladder pain and urinary frequency flare with certain triggers if you have this condition. Learn about treatments and self-care.
Disease
Interstitial lung disease
This group of lung diseases cause progressive lung tissue scarring and affect your ability to breathe and get enough oxygen into your bloodstream.
Disease
Intestinal ischemia
Learn about what happens when blood flow to part of the small or large intestine is blocked, and how this serious condition is treated.
Disease
Intestinal obstruction
A blocked intestine needs prompt medical care. Learn about symptoms and the wide range of causes for this serious but treatable digestive disorder.
Disease
Intracranial hematoma
This collection of blood within the skull is a serious, possibly life-threatening, complication of a head injury.
Disease
Intracranial venous malformations
Find out more about the diagnosis and treatment of these unusually enlarged veins in the brain.
Disease
Intussusception
This rare but serious disorder occurs when one part of the intestine slides into another part, like a collapsible telescope.
Disease
Invasive lobular carcinoma
Breast cancer that begins in the milk-producing glands of the breast is uncommon. Learn what sets lobular carcinoma apart from other breast cancer types.
Disease
Iritis
Learn about who's at risk of this eye condition and why you should get treatment right away if you have symptoms.