A neurogenetic disorder caused by deletion or mutation of UBE3A gene on maternal chromosome 15. Characterized by severe developmental delay, speech impairment, ataxia, seizures, and happy demeanor with frequent laughing/smiling.

A rare neurodegenerative disorder caused by ATM gene mutations affecting DNA repair. Characterized by progressive cerebellar ataxia, ocular telangiectasia, immunodeficiency, and increased cancer risk (particularly lymphoma and leukemia).

Hereditary cancer syndrome caused by mutations in BRCA1 or BRCA2 tumor suppressor genes. Significantly increased lifetime risk of breast cancer (up to 70%), ovarian cancer (up to 44%), prostate cancer, and pancreatic cancer.

A group of autosomal recessive disorders affecting adrenal steroidogenesis. Most common is 21-hydroxylase deficiency causing cortisol and aldosterone deficiency with androgen excess. Can cause life-threatening salt-wasting crisis in newborns.

An inherited disorder of renal amino acid transport causing excessive urinary excretion of cystine and other dibasic amino acids. Cystine precipitates forming recurrent kidney stones (cystine calculi), potentially leading to renal damage.

An autoimmune condition where the pancreas produces little or no insulin. Previously known as juvenile diabetes, it typically appears during childhood or adolescence but can develop in adults. Requires lifelong insulin therapy.

A chronic metabolic disorder characterized by high blood sugar, insulin resistance, and relative lack of insulin. The most common form of diabetes, accounting for 90-95% of cases. Often preventable and sometimes reversible with lifestyle changes.

Inflammation or infection of diverticula (small pouches that form in the colon wall). Common in older adults in Western countries. Can range from mild to severe with complications like abscess, perforation, or fistula formation.

A condition in which excess fat builds up in the liver, not due to alcohol use. The most common chronic liver disease worldwide, affecting 25% of the global population. Ranges from simple steatosis to nonalcoholic steatohepatitis (NASH) which can progress to cirrhosis.

Inflammation of the stomach lining. Can be acute (sudden onset) or chronic (long-term). Common causes include H. pylori infection, NSAID use, and excessive alcohol consumption. Can lead to ulcers and increased stomach cancer risk if untreated.

A chronic digestive disease where stomach acid or bile irritates the food pipe lining. Occurs when the lower esophageal sphincter relaxes abnormally or weakens. Affects approximately 20% of adults in Western countries. Can lead to serious complications if untreated.

The most common lysosomal storage disorder, caused by deficiency of glucocerebrosidase (GBA gene). Glucocerebroside accumulates in macrophages (Gaucher cells) in spleen, liver, bone marrow. Three types: Type 1 (non-neuronopathic, most common), Types 2 & 3 (neuronopathic).

Diabetes diagnosed for the first time during pregnancy. Affects approximately 2-10% of pregnancies worldwide. Increases risk of complications for both mother and baby but usually resolves after delivery. Women with GDM have 50% lifetime risk of developing type 2 diabetes.

An inherited disorder affecting glycogen metabolism due to glucose-6-phosphatase deficiency. Glycogen accumulates in liver and kidneys causing hepatomegaly, hypoglycemia, and lactic acidosis. Several subtypes with varying severity.

A condition where the thyroid gland produces too much thyroid hormone (T3 and T4). Accelerates the body's metabolism, causing unintentional weight loss, rapid heartbeat, sweating, and nervousness. Graves' disease is the most common cause.

A condition where the thyroid gland doesn't produce enough thyroid hormones. Slows down many of the body's functions. Hashimoto's thyroiditis is the most common cause in developed countries. Can occur at any age but is more common in older women.

A group of inherited retinal dystrophies causing severe visual impairment at birth or early infancy. Most common genetic cause of childhood blindness. Multiple genetic subtypes; RPE65-related LCA treatable with gene therapy.

A rare hereditary cancer syndrome caused by TP53 gene mutations. Extremely high lifetime cancer risk (nearly 100% in females, ~70% males). Early-onset cancers including sarcomas, breast cancer, brain tumors, and adrenal cortical carcinoma.

Open sores that develop on the inside lining of the stomach (gastric ulcers) and the upper portion of the small intestine (duodenal ulcers). Most common cause is H. pylori infection or NSAID use. Affects approximately 4% of the global population.

A chronic autoimmune liver disease characterized by progressive destruction of small intrahepatic bile ducts, leading to cholestasis and cirrhosis. Predominantly affects middle-aged women. Previously called primary biliary cirrhosis.

A chronic cholestatic liver disease characterized by inflammation and fibrosis of bile ducts, eventually leading to cirrhosis. Strongly associated with inflammatory bowel disease (70% of patients). Increased risk of cholangiocarcinoma and colorectal cancer.

An extremely rare, fatal genetic disorder causing premature aging in children. Caused by LMNA gene mutation producing progerin. Autosomal dominant, usually de novo mutations. Average lifespan 14.5 years. Death typically from cardiovascular complications.

A group of inherited retinal dystrophies causing progressive vision loss due to photoreceptor degeneration. Most common inherited retinal disease. Can be isolated or part of syndromes (Usher syndrome, Bardet-Biedl syndrome).

A fatal autosomal recessive lysosomal storage disorder caused by HEXA gene mutation, resulting in deficiency of beta-hexosaminidase A. GM2 ganglioside accumulates in neurons. Most common in Ashkenazi Jewish, French Canadian, and Cajun populations. Infantile form most severe.

An inherited disorder causing both hearing loss and progressive vision loss (retinitis pigmentosa). Most common cause of combined deafness and blindness. Three clinical types with varying severity and progression.

A mosquito-borne flavivirus most commonly transmitted by Culex species mosquitoes. Can cause neurological disease in humans. Birds are primary hosts. First identified in Uganda in 1937; emerged in North America in 1999.

The first described primary immunodeficiency, caused by BTK gene mutations leading to absent B cells and severe hypogammaglobulinemia. Affected males develop recurrent bacterial infections starting after 6 months when maternal antibodies wane.

X-linked lysosomal storage disorder causing accumulation of globotriaosylceramide due to alpha-galactosidase A deficiency. Affects multiple organs including kidneys (proteinuria, progressive renal failure), heart, and nervous system. Renal involvement is major cause of morbidity.

The most common lysosomal storage disorder, caused by glucocerebrosidase deficiency. Characterized by hepatosplenomegaly, cytopenias, and bone disease. Non-neuronopathic form (Type 1) accounts for 90% of cases. Most common in Ashkenazi Jewish population.

The most common glycogen storage disease, caused by glucose-6-phosphatase deficiency (Type Ia) or translocase deficiency (Type Ib). Characterized by severe fasting hypoglycemia, hepatomegaly, lactic acidosis, hyperuricemia, and hyperlipidemia.

Inability to fully digest lactose, the sugar in milk and dairy products, due to deficiency of lactase enzyme in the small intestine. Very common worldwide, especially in certain ethnic groups. Not dangerous but can cause uncomfortable symptoms.

A viral respiratory illness caused by Middle East Respiratory Syndrome Coronavirus (MERS-CoV). First reported in Saudi Arabia in 2012. Transmitted from camels to humans and person-to-person in close contact. Case fatality rate approximately 35%. Most cases in Arabian Peninsula.

A sudden episode of kidney failure or kidney damage that happens within a few hours or days. Causes waste products to build up in the blood and makes it hard for kidneys to maintain the right balance of fluids. Can be prerenal, intrinsic, or postrenal.