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Marfan Syndrome
- Autosomal Dominant
- Defect in fibrillin-1 (connective tissue disorder)
- Skeletal abnormalities - tall, lax joints
- Ocular changes - ectopia lentis
- Cardiovascular lesions - aortic dilation, mitral prolapse
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Ehlers-Danlos Syndromes
- Autosomal Dominant or Recessive
- Defect in fibrillar collagen synthesis or structure
- Hyperextensible skin
- Hypermobile joints
-
Familial Hypercholesterolemia
- Autosomal Dominant
- Defect in receptor for LDL
- Elevated cholesterol leads to premature atherosclerosis
- *Statins - inhibit HMG CoA reductase, lowering cholesterol synthesis, increasing LDL synthesis
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Lysosomal Storage Diseases
Defects in enzymes essential for normal lysosome function
-
Tay-Sachs Disease
- Lysosomal Storage Disease
- Autosomal Recessive
- Accumulation of Gm2 gangliosides
- Most commonly failure of hexosaminidase A
- Accumulation in many tissues - clinically in CNS, ANS and retina
- Progressive destruction of neurons
- *Cherry red dot on macula
-
Niemann-Pick Disease (A, B)
- Lysosomal Storage Disease
- Autosomal Recessive
- Deficiency of sphingomyelinase
- Accumulation of Sphingomyelin
- Massive Splenomegaly
- Shrunken gyri, widened sulci
- Type A - severe infantile form (CNS pathology)
- Type B - Orangomegaly without CNS pathology
-
Niemann-Pick Disease Type C
- Lysosomal Storage Disease
- Autosomal Recessive
- Failure in lipid transport out from lysosomes
- Cholesterol and ganglioside accumulation
-
Gaucher Disease
- Lysosomal Storage Disease
- Autosomal Recessive
- Affects phagocytes, sometimes CNS
- Accumulation of glucocerebroside
- Distended phagocytes called Gaucher Cells
- Progressive neural destruction
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Mucopolysaccharidoses
- Lysosomal Storage Disease
- Autosomal and X-linked Recessive
- Accumulation of glycosaminoglycans
- Coarse facial features, corneal clouding, joint stiffness, mental retardation
- Hepatospenomegaly, skeletal deform., CNS lesions
-
Glycogen Storage Diseases
- Autosomal Recessive
- Deficiency in an enzyme involved in synthesis or sequential degradation of glycogen
-
Alkaptonuria (Ochronosis)
- Autosomal Recessive
- Accumulation of homogentisic acid (pigment) in body
- Deposits in cartilage - more brittle and fibrillated
-
Mosaicism
Mitotic erros in early development giving rise to two or more population of cells with different chromosomal complements in one individual
-
Trisomy 21
- Usually maternal nondisjunction
- Common: congenital heart disease, leukemia, Alzheimer's disease, immune abnormalities
-
Edwards Syndrome
- Trisomy 18
- Severe malformations - congenital heart defects, renal malformations, mental retardation
-
Patau Syndrome
- Trisomy 13
- Severe malformations - microcephaly, cleft lip/palate, polydactyly, cardiac defects, renal defects
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Chromosome 22q11.2 Deletion Syndrome
- Congenital heart defects
- Palate abnormalities
- Facial dysmorphism
- Developmental delay
- T-cell immunodeficiency
- Hypocalcemia
- High risk of psychotic illness
-
Lyon hypothesis
- Only one X chromosome is activated in each cell
- Inactivation of either X occurs at random in blastocyst
- All cells derived from same precursor cell share same X inactivation
-
Klinefelter Syndrome
- 47 XXY
- Male hypogonadism, infertility
-
Turner Syndrome
- 45 X
- Female hypogonadism
- Short
- Coarctation of aorta
- Infertility
- Abnormal sex characteristics
-
Complete androgen insensitivity syndrome
- Form of male pseudohermaphroditism
- Defect in androgen action
-
Fragile-X Syndrome
- X-linked Recessive
- Long unstable repeating sequence of 3 nucleotides
- Macro-orchidism (large testes)
- Mental retardation
-
Prader-Willi syndrome
- Deletion on paternal chromosome 15
- Mental retardation, short, hypotonia, hyperphagia
- Obesity, small hands/feet, hypogonadism
-
Angelman syndrome
- Deletion on maternal chromosome 15
- Mental retardation, ataxic gait
- Seizures
- Inappropriate laughter
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