Lipid

Question 1

[Met/Lipid/SLOS]

Biochemical defects of Smith-Lemli-Opitz syndrome?

Answer 1

Deficiency of the enzyme 7-dehydrocholesterol (7-DHC) reductase
-> an abnormality in cholesterol metabolism

Question 2

[Met/Lipid/SLOS]

Characteristics of Smith-Lemli-Opitz syndrome? (4)

Answer 2

1. Prenatal and postnatal growth restriction
2. Microcephaly
3. Moderate-to-severe intellectual disability
4. Multiple major and minor malformations
   - distinctive facial features
   - cleft palate
   - cardiac defects
   - underdeveloped external genitalia in males
   - postaxial polydactyly, and 2-3 syndactyly of the toes.

Question 3

[Met/Lipid/SLOS]

Congenital anomalies of Smith-Lemli-Opitz syndrome? (5)

Answer 3

1. Distinctive facial features
   - narrow forehead, epicanthal folds, ptosis, short mandible with preservation of jaw width, short nose, anteverted nares, and low-set ears
2. Cleft palate
3. Cardiac defects
4. Underdeveloped external genitalia in males
5. Postaxial polydactyly, and 2-3 syndactyly of the toes

Question 4

[Met/Lipid/SLOS]

Biochemical findings of Smith-Lemli-Opitz syndrome? (2)

Answer 4

Elevated serum concentration of 7-dehydrocholesterol (7-DHC)
Low serum concentration of cholesterol

Question 5

[Met/Lipid/SLOS]

Inheritance pattern of Smith-Lemli-Opitz syndrome?

Answer 5

Autosomal recessive

Question 6

[Met/Lipid/SLOS]

Smith-Lemli-Opitz syndrome

Type 1 is classic form and is associated with ____
Type 2 is associated with ____ and ____, fatal within a year

Answer 6

Type 1 is classic form and is associated with pyloric stenosis
Type 2 is associated with postaxial polydactyly and Hirschsprung disease, fatal within a year

Question 7

[Met/Lipid/Basic]

Examples of inborn errors of cholesterol synthesis in complex-molecule defects? (4)

Answer 7

Smith-Lemli-Optiz syndrome
Hypercholesterolemia
Apolipoprotein E deficiency
Tangier disease

Question 8

[Met/Lipid/Hyperlipoproteinemia]

Examples of Hyperlipoproteinemia disorders (3)?

Answer 8

Familial combined hyperlipidemia:
- Overproduction of VLDL and apoB
- LDL and/or TG, no xanthoma

Familial hypercholesterolemia
- LDL receptor protein defect
- Total cholesterols, LDL, Xanthomas

Lipoprotein-lapse deficiency
- Very high TG ~ 10K, creamy blood

Question 9

[Met/Lipid/Hyperlipoproteinemia]

Cause and characteristics of Familial combined hyperlipidemia?

Answer 9

Overproduction of VLDL and apoB
High LDL and/or TG, no xanthoma

Question 10

[Met/Lipid/Hyperlipoproteinemia]

Cause and characteristics of Familial hypercholesterolemia?

Answer 10

LDL receptor protein defect
High Total cholesterols, LDL, Xanthomas

Question 11

[Met/Lipid/Hyperlipoproteinemia]

Characteristics of Lipoprotein-lapse deficiency?

Answer 11

Very high TG ~ 10K, creamy blood
Abdominal pain, pancreatitis
Retinal deposits

Question 12

[Met/Lipid/Hypolipoproteinemia]

Examples of Hypolipoproteinemia disorders? (4)

Answer 12

Abetalipoproteinemia
Smith-Lemli-Optiz syndrome
Tangier disease
Barth syndrome

Question 13

[Met/Lipid/Hypolipoproteinemia]

Characteristics of Abetalipoproteinemia?

Answer 13

Fat malabsorption: Vit E deficiency
Retinal/nervous: cerebella ataxia, retinitis pigmentosa, acanthocytosis

Question 14

[Met/Lipid/Hypolipoproteinemia]

Another name and characteristics (3) of Tangier disease?

Answer 14

Familial High-Density Lipoprotein (HDL) Deficiency
Yellow-orange tonsils, hepatosplenomegaly, and peripheral neuropathy

Question 15

[Met/Lipid/Chylomicron]

Which disease?

Diarrhea, steatorhea
Low serum cholesterol
(No acanthocytosis, retinitis pigmentosa, or neurologic)

Answer 15

Chylomicon retention disease
(Defect in exocytosis of chylomicrons)