Exam 2 Inherited Diseases

Achondroplasia

Autosomal dominant: Dwarfism associated with defects in growth regions of long bones.

Brachydactyly

Autosomal dominant: Malformed hands with shortened fingers.

Camptodactyly

Autosomal dominant: Stiff, permanently bent little fingers.

Crouzion Syndrome

Autosomal dominant: Defective development of midface region; protruding eyes and hooked nose.

Familial Hypercholesterolemia

Autosomal dominant: Elevated cholesterol levels; predisposes to plaque formation and cardiovascular disease.

Adult Polycystic Kidney Disease

Autosomal dominant: Formation of cysts in kidneys; leads to hypertension and kidney failure

Huntington Disease

Autosomal dominant: Progressive degeneration of the nervous system and dementia in mid-age; early death; associated with CAG repeats.

Hypercalcemia

Autosomal dominant: Elevated levels of calcium in blood serum

Marfan Syndrome

Autosomal dominant: Connective tissue defect; may cause death from aortic failure; individuals often have tall height phenotype.

Nail-Patella Syndrome

Autosomal dominant: Absence of nails and kneecaps

Ehlens Donlon’s Syndrome

Connective Tissue Disorder

Loose joints

Porphyria

Autosomal dominant: Inability to metabolize porphyrins; episodes of mental disturbance

Albinism

Autosomal recessive: Absence of melanin pigment in skin, eyes, and hair; also occurs in plants (lack of chlorophyll).

Ataxia Telangiectasia

Autosomal recessive: Progressive degeneration of the nervous system.

Bloom Syndrome

Autosomal recessive: Dwarfism, skin rash, and increased cancer risk.

Cystic Fibrosis

Autosomal recessive: Mucus production blocks ducts of glands and lung passages; often fatal in early adulthood; associated with defective chloride ion channels

Fanconi Anemia

Autosomal recessive: Slow growth, heart defects, and high rate of leukemia.

Galactosemia

Autosomal recessive: Accumulation of galactose in the liver; leads to mental retardation.

Phenylketonuria (PKU)

Autosomal recessive: Excess accumulation of phenylalanine in blood; causes mental retardation if untreated.

Sickle Cell Anemia

Autosomal recessive: Abnormal hemoglobin leads to blood vessel blockage and relatively early death.

Thalassemia

Autosomal recessive: Improper hemoglobin production; symptoms range from mild to severe

Xeroderma Pigmentosum

Autosomal recessive: Lack of DNA repair enzymes; extreme sensitivity to UV light; high risk of skin cancer and early death.

Tay-Sachs Disease

Autosomal recessive: Impaired metabolism of gangliosides in nerve cells; associated with Ashkenazi Jewish population; early death.

Lesch-Nyham Syndrome

X-linked recessive: mental retardation, self-multilation, early death

Color Blindness

X-linked recessive: Inability to distinguish certain colors.

• Green blindness: insensitivity to green light; ~60–75% of colorblind cases

• Red blindness: insensitivity to red light; ~25–40% of colorblind cases

Hemophilia

X-linked recessive: Inability of blood to clot.

• A: caused by lack of clotting factor VIII (8)

• B: caused by lack of factor IX (9)

Ichthyosis

X-linked recessive: Skin disorder caused by large, dark scales on extremities and trunk.

Muscular Dystrophy

X-linked recessive: Progressive, fatal condition causing muscle wasting.

Fabry Disease

X-linked recessive: Metabolic defect caused by lack of enzyme alpha-galactosidase A; leads to progressive cardiac and renal problems and early death.

Adrenoleukodystrophy

X-linked recessive: Atrophy of adrenal glands; mental degeneration; death 1–5 years after onset.

Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency

X-linked recessive: Usually benign but can cause severe or fatal anemia when exposed to certain foods (e.g., fava beans) or drugs.

Congenital Generalized Hypertrichosis

X-linked dominant: Excessive hair growth over the entire body (except palms and soles); historically referred to as “ape men” or “werewolves.”

Alport Syndrome

X-linked dominant: Deafness and inflammation of kidney tubules.

Incontinentia Pigmenti:

X-linked dominant: Swirls of skin color; hair loss; seizures; abnormal teeth.

Fragile X Syndrome:

X-linked dominant: Mental retardation; characteristic facial features; large testicles.

Coffin-Lowry Syndrome:

X-linked dominant: Facial dysmorphism; digit abnormalities; psychomotor and growth retardation.

Rett’s Syndrome:

X-linked dominant: Occurs almost exclusively in girls; causes severe impairments affecting speech, walking, eating, and breathing.

Familial Rickets:

X-linked dominant: Short stature; skeletal deformities; bone pain; muscle weakness