Genetic Disorders Flashcards
1
Q
- Why does familial hypercholesterolemia occur?
- What is the deficiency in galactosemia?
- Glucose-6-phosphate dehydrogenase deficiency: Inheritance pattern? Associated with?
A
- Because reduced synthesis or function of LDL receptors results in reduced LDL uptake and increased synthesis of cholesterol.
- Galactose-1-phosphate uridyltransferase resulting in the accumulation of galactose
- x-linked; hemolytic anemia from oxidative stress
2
Q
Marfan Syndrome
- Defect is in?
- Role of this protein?
- Results in?
- Clinical manifestation?
A
- Extracellular matrix protein fibrillin-1
- Important component of microfibril elastic fibers that are abundant in the aorta, ligaments, and ciliary zonules of the eye
- Disruption of the assembly of the microfibrils; there is also _excessive TGFb _
- tall, long extremities and fingers, lax joint ligaments, deformed chest, _ectopia lentis _(lens out and up), mitral valve prolapse
3
Q
Ehlers-Danlos Syndrome
- Inheritance pattern?
- This is a group of disorders associated with defects of what?
- Clinical manifestation of classic form?
- What occurs in the hypermobility variant?
- What is vascular EDS?
- What 2 types have a defective conversion of type I procollagen to collagen?
- What can occur in other variants?
A
- Most are autosomal dominant (some are AR or X-linked)
- Structure or synthesis of fibrillar collagen
- Skin tends to be hyperextensible and vulnerable to damage from minor trauma and hypermobile joints
- the joints are painful and may dislocate
- Type III collagen - rupture of the uterus, colon, and large arteries are possible
- _Arthrochalasia ED_S and Dermatosparaxsis EDS
- diaphragmatic herniation or ocular fragility
4
Q
Familial Hypercholesterolemia
- Mutation of? Result?
- Normal LDL clearance mechanism?
- Mutated clearance?
- Inheritance Pattern?
- Treatment?
A
- The gene for LDL receptor involved in transport and metabolism of cholesterol –> increase plasma cholesterol–> premature atherosclerosis
- Uptake mediated by binding to LDL receptors that recognize ApoB–> taken up into liver –> endosome fuses with the lysosome –> LDL dissociates –> metabolized
- NO or LOW uptake of LDL
- Autosomal dominant
- statins
5
Q
Tay-Sachs
- Also known as?
- Deficiency in what enzyme?
- Gene location? Inheritance pattern?
- Pathogenesis?
- What appears in the macula? What happens to neurons?
- Symptoms? Age?
A
- GM2 Gangliosidosis
- Hexosaminidase-alpha
- 15q; autosomal recessive
- GM2 gangliosides accumulate - particularly in the CNS, ANS, and the Retina
- Cherry red spot; lysosomes contain whorls of layers of membranes
- Motor and mental deterioration; 6 months
6
Q
Niemann Pick
- Deficiency in? What thus accumulates in lysosomes?
- Inheritance pattern?
- Type A: Who? What occurs? Presentation?
- Type B: presentation? Survival?
- What happens to all involved organs?
A
- Sphingomyelinase; sphingomyelin
- Autosomal recessive
- Infants; complete deficiency; excensive CNS involvement, hepatosplenomegaly, and death by age 3
- Hepatosplenomegaly, insufficiency, little or no CNS involvement; into adulthood
- They become enlarged
7
Q
Niemann Pick Disease type C
- Inheritance pattern?
- Mutation of NPC1 (most common) causes?
- Mutation of NPC2 causes?
- Clinical manifestations?
A
- Autosomal Recessive
- Impaired regulation of cholesterol in cells
- Impaired release of free cholesterol from lysosomes
- Neuronal degeneration and hepatosplenomegaly
8
Q
Gaucher Disease
- Inheritance pattern?
- Mutation in the gene that codes for what?
- Deficiency results in accumulation of ____. Where?
- Treatment?
A
- Autosomal recessive
- Glucocerebrosidase
- Glucocerebroside accumulation in lysosomes
- recombinant glucocerebrosidase, bone marrow transplantation, and/or gene therapy
9
Q
Gaucher Disease Type I
- Where do glucocerebrosides collect?
- What major organ is not involved?
- Onset (infant/child/adult/elderly)?
- Presentation?
A
- Phagocytes of spleen, bone marrow, lymph nodes/tissue
- Brain
- Adulthood
- Hepatosplenomegaly, fatigue, anemia, bleeding, bone pain, and pathological fractures
10
Q
Gaucher Disease Type II
- Where do glucocerebrosides collect?
- Age of onset?
- Presentation?
- Death occurs from?
Gaucher Disease Type III
- Similar to type II but?
A
- Phagocytes of spleen, bone marrow, lymph nodes/tissue, lung, and CNS
- First few months of life
- Same as type I but with emphasis on CNS manifestation
- Neurologic degeneration and respiratory complication
- Age of onset is mid to late childhood and they live until 2nd or 3rd decade
11
Q
Mucopolysaccharidoses
- Lysosomal storage disorder associated with deficiency of?
- This results in?
- Characteristic presentation?
- 2 examples?
A
- Degradation of glycosaminoglycans (dermatan sulfate, heparin sulfate, keratin sulfate etc)
- HMW glycosaminoglycans accumulate in tissue
- Organomegaly and rapid mental deterioration
- Hunter and Huler’s syndromes
12
Q
Hurler’s Syndrome
- Inheritance pattern?
- Deficiency of? Results in accumulation of?
- Presentation?
- Age of Death?
- “Managed” how?
A
- Autosomal recessive
- alpha-L-iduronidase; dermatan and heparin sulfate
- growth/mental retardation, coarse facial features, skeletal deformities, corneal clouding, and heart disease
- 6-10 years old
- Enzyme replacement therapy and or bon marrow transplant
13
Q
Hunter Syndrome
- Inheritance pattern?
- Deficiency of? Results in accumulation of?
- Onset and symptoms?
A
- X-linked recessive (males)
- Iduronate-2-sulfatase; dermatan and heparin sulfate
- Similar to hurlers but milder (no corneal clouding) but death before 15
14
Q
Von Gierke Disease
- Deficiency in? Causes?
- Presentation?
- Inheritance pattern?
A
- Glucose-6-phosphatase - doesnt allow the production of free glucose from glycogen –> hypoglycemia
- Glycogen build up in liver: hepatomegaly and kidney
- Autosomal recessive
15
Q
McArdle Disease
- Deficiency in?
- Results in accumulation of glycogen where?
- Presentation?
- Inheritance pattern?
A
- Muscle phosphorylase
- Muscle - myopathic glycogenosis
- Painful muscle cramps and weakness (especially following exercise)
- Autosomal Recessive