| Name | How Is It Inherited? | What Is the Problem? | When Does It Become Symptomatic or Apparent? | How Common Is It?* |
|---|
| Alpha1-antitrypsin deficiency | Autosomal dominant | Deficiency of enzyme that protects liver and lungs from enzymatic injury. Results in early onset of chronic obstructive pulmonary disease (COPD) or liver disease. There are more than 70 genetic variants. | Childhood: liver disease; Adulthood: lung disease | Homozygotes: 1:3000 |
| Autosomal dominant polycystic kidney disease | Autosomal dominant | Abnormal cell membrane protein predisposes to cyst formation in epithelial organs, esp. the kidney. Causes about 5% of all end-stage renal disease in the U.S. | Renal failure usually by ages 55–60 | 1:1000 (Europeans) |
| Chronic granulomatous disease | X-linked or autosomal recessive | Defect in phagocytic cells results in susceptibility to recurrent severe infections | Infancy/early childhood | 1:300,000 |
| Color blindness (red-green) | X-linked recessive | Abnormalities of visual pigment expression in retinal cone cells | Childhood | 1:12–20 males; 1:200 females |
| Cystic fibrosis | Autosomal recessive | Abnormality in cellular sodium and chloride management. Infant may have meconium ileus at birth; later, azoospermia, biliary, lung, pancreatic, and sinus disease | Early childhood | Heterozygotes: 1:2000 (United Kingdom); 1:3500 (U.S.); 1:350,000 (Japan) |
| Diabetes mellitus, type 2 | Polygenic | Resistance to the action of insulin in muscles and other peripheral tissues; insufficient insulin production by the pancreas. Hyperglycemia, with metabolic damage to eyes, kidneys, nerves, and blood vessels | Often at onset of inactivity; patient is overweight or obese, usually in adulthood | 1–30:1000 per year; highest incidence in some ethnic groups (Africans, Hispanics, Native Americans, Polynesians) |
| Duchenne muscular dystrophy | X-linked recessive | Missing protein within myocyte membranes results in weakness of proximal muscles, with difficulty walking, frequent falling, and pseudohypertrophy of muscle groups | Early childhood | 1:3000–5000 (Europeans) |
| Familial adenomatous polyposis | Autosomal dominant | Faulty gene results in growth of hundreds of polyps within the large bowel, with the potential for malignant transformation | Adolescence/early adulthood | 1–2:1,000,000 |
| Familial hypercholesterolemia | Autosomal dominant | Excessively high levels of low-density lipoprotein and total cholesterol, resulting in premature atherosclerosis | Homozygotes may have heart attacks in their 20s | Heterozygotes: 1:500; Homozygotes; 1:3,000,000 |
| Hemophilia A | X-linked | Insufficient production of clotting factor VIII. Produces bleeding, esp. into injured joints or after surgery | Early childhood | 1:5000 to 10,000 males |
| Hemophilia B | X-linked | Insufficient production of clotting factor IX. Produces bleeding, esp. into injured joints and after surgery | Early childhood | 1:30,000 males |
| Hereditary hemochromatosis | Autosomal recessive | Increased iron absorption from the GI tract. Iron deposits gradually accumulate in and damage joints, pancreas, liver, heart, testes | Middle age | Heterozygotes: 1:8; Homozygotes: 1:200 |
| Huntington disease | Autosomal dominant | Degeneration of the caudate nucleus of the brain, with early onset dementia, schizophreniform illnesses, and movement disorders (chorea) | Middle age | 1:115,000 |
| Long QT syndrome | Autosomal recessive; autosomal dominant | Abnormalities in management of sodium by myocytes results in prolonged action potentials and cardiac depolarization, producing life-threatening heart rhythm disturbances. Recessive form (very rare) associated with deafness | Childhood and adolescence | Not well quantified |
| Marfan syndrome | Autosomal dominant | Mutations in a gene that produces extracellular matrix protein result in tall body type, with elongated fingers; flat feet; hernias; hyperextensible joints; sternal deformities; and potential for aortic dissection | Risk of aortic dissection highest after age 50 | 1:10,000 |
| Neurofibromatoses I and II | Autosomal dominant | Absence of a tumor-suppressing gene results in growth of multiple skin and nerve tumors | Infancy | 1:3000 |
| Phenylketonuria (hyperphenylalanemia) | Autosomal recessive | Inability to convert phenylalanine to tyrosine. Results in eczema and hypopigmentation, hyperactivity, mental retardation, and seizures | Infancy | 1:16,000 (general U.S. population) to 1:200,000 (lower incidence in African Americans and Eastern European Jews) |
| Porphyria, acute intermittent | Autosomal dominant | Attacks of abdominal pain, sometimes associated with autonomic dysfunction, muscle weakness, seizures | Adolescence | 1:10,000 (most common in Northern Europeans) |
| Rett syndrome | X-linked dominant | After a brief period of normal development, young girls regress neurologically, developing speech disturbances, loss of normal hand movements, seizures, ataxia, and autism | 6–18 months old | 1:10–15,000 |
| Sickle cell anemia | Autosomal recessive | Abnormal amino acid in hemoglobin molecule results in deformed red blood cells that may cause infarcts in bones and other internal organs. High risk of pneumococcal infections and painful crises | Early childhood | Heterozygotes: (African Americans) 8–13:100; (Brazilians) 5–6:100 |
| Tay-Sachs disease | Autosomal recessive | Deficiency of enzyme results in accumulation of sphingolipids in the brain, causing mental retardation, blindness, paralysis | Early childhood | Heterozygotes (Eastern European Jews) 1:25 |