Brs Biochem 19/23

Front 1

Set 19 Q: This lab technique, based on antigen-antibody interactions, detects the presence of a protein in a clinical sample; it uses an enzyme that produces a chemiluminence product in the presence of the protein of interest.

Back 1

Enzyme-linked immunosorbent assay (ELISA) - this is commonly used as a screening test to determine whether infected patients are producing antibodies to HIV. The test is highly sensitive although not extremely specific for such infections.

Front 2

Set 19 Q: This molecular technique involves the separation of protein via electrophoresis and transfer to a membrane, followed by detection of cognate antigens with antibodies.

Back 2

Western Blot - this test is used to confirm HIV infection in patients who have a positive ELISA test, as it is more specific. Antibodies to individual HIV proteins are found, with a final positive result requiring the detection of antibodies to two or more viral antigens.

Front 3

Set 19 Q: The karyotype 45XO of this disorder can be confirmed by the lack of a Barr body and an inactivated, condensed X chromosome in females, normally detected in a scraping of the inner cheek (buccal smear)

Back 3

Turner Syndrome - decreased levels of estrogens lead to female hypogonadism and the replacement of the ovaries by fibrous streaks; other congenital anomalies include coarctation of the aorta and the presence of a horseshoe kidney.

Front 4

Set 19 Q: The karyotype of this disorder is 47, XXY. It is often due to a nondisjunction in the female gamete; thus there is an increased incidence with increasing maternal age

Back 4

Klinefelter syndrome - these patients have low testosterone levels and high levels of FSH (which stimulates sertoli cells to make sperm. No inhibin feedback= high FSH), atrophic testes that lead to infertility. They also lack secondary male characteristics, resulting in a eunuchoid appearance with gynecomastia.

Front 5

Set 19 Q: This condition results from the acquisition of a chromosome containg the long arm of chromosome 21 and another acrocentric chromosome, such as 22 or 14, as well as another intact chromosome 21 in the maternal gamete.

Back 5

Down syndrome due to a robertsonian translocation - unlike most causes of Down syndrome [non-disjunction], this causes is independent of maternal age and is frequently familial

Front 6

Set 19 Q: This disorder is due to a meiotic nondisjunction, resulting in trisomy 18

Back 6

Edward Syndrome - patients present with mental retardation, micrognathia, low set ears, rockerbottom feet, and congenital heart disease

Front 7

Set 19 Q: This disorder results from a meiotic nondisjunction, resulting in trisomy 13

Back 7

Patau's syndrome - patients present with mental retardation, microphthalmia, cleft lip and Palate, and Polydactyly, holoProsencephaly

Front 8

Set 19 Q: This condition results from the inheritance of a maternally derived chromosome 15, with a deletion of imprinted genes (ie: deletion of a normally active maternal allele)

Back 8

Angelman Syndrome - patients present with mental retardation, ataxia, seizures, and inappropriate laughter, leading to the term "happy puppet." - imprinting: at a single locus only one allele is active, the other allele is inactivated.

Front 9

Set 19 Q: This condition results from the deletion of genetically imprinted genes on the paternally inherited chromosome 15 (ie: deletion of normally active paternal allele)

Back 9

Prader-Willi syndrome - patients with this disorder present with mental retardation, short stature, hypogonadism, and obesity, as a result of a voracious appetite - imprinting: at a single locus only one allele is active, the other allele is inactivated.

Front 10

Set 19 Q: This group of hereditary disorders is characterized by transmission from mother to child in each generation but no transmission from the affected father

Back 10

Mitochondrial disorders - the mitochondria has its own closed circular genome, which encodes 13 proteins for the inner membrane complexes, 22 tRNAs, and 2 rRNAs. The genetic code for the mitochondrial genome is slightly different than that used in the nucleus. - blotchy red muscle fibers on Gomori Trichrome stain is indicative of mitochondrial myopathy

Front 11

Set 19 Q: These patients have an additional Y chromosome, resulting in a total of 47 chromosome.

Back 11

XYY syndrome - patients present as tall males with severe acne and sometimes with mild retardation mistakenly described in the past as occurring with increased incidence among violent criminals.