Molecular Genetics — Flashcards

Flashcard 371: - Karyotype of Müllerian Agenesis = _____ and ↔ testosterone levels - Karyotype of Androgen Insensitivity Syndrome = _____ and ↑ testosterone levels

Answer: XX

Extra:  https://onlinemeded.org/spa/gynecology/primary-amenorrhea/acquire?ref=anki 

Flashcard 372: 5α-reductase deficiency = _____

Answer: 46XY

Extra:  https://onlinemeded.org/spa/obgyn?ref=anki 

Flashcard 373: What serum marker is characteristically elevated in choriocarcinoma? _____

Answer: β-hCG

Extra: β-hCG is characteristically elevated in choriocarcinoma, hydatidiform moles, and gestational trophoblastic disease. It is also used to monitor treatment response and screen for recurrence.

Flashcard 374: Chronic myeloproliferative disorders (except CML) are associated with _____ mutations - the mutation is in a gene encoding a(n) tyrosine kinase, which causes tyrosine hyperphosphorylation and hypersensitivity of progenitor cells to cytokines, prolonging cellular growth

Answer: V617F JAK2

Extra:   https://onlinemeded.org/spa/hematology-oncology/leukemia/acquire?ref=anki 

Flashcard 375: _____

Answer: G

Extra:  https://onlinemeded.org/spa/surgery?ref=anki 

Flashcard 376: HbH and Hgb Barts = _____ thalassemia ↑ HbA2 and ↑ HbF = _____ thalassemia

Answer: alpha

Extra:  https://onlinemeded.org?ref=anki 

Flashcard 377: A 6-year-old African American boy presents with easy fatigability and splenomegaly. CBC shows mild anemia. Hemoglobin electrophoresis shows a hemoglobin variant that migrates more slowly toward the anode than both HbA and HbS. What mutation is the most likely cause of this patient's condition?

Answer: Missense mutation (Glutamic acid to Lysine substitution at position 6 of the β-globin chain) **Diagnosis:** Hemoglobin C (HbC) disease **Electrophoresis migration (toward anode):** HbA > HbS > HbC (A Fat Slow Crawl)

Extra: - **HbC disease** is caused by a missense mutation where a negatively charged glutamic acid is replaced by a positively charged lysine. - **Clinical features:** Mild hemolytic anemia, splenomegaly, and HbC crystals (rod-shaped) in red blood cells. - **Electrophoresis:** Since lysine is more positive than valine (HbS) or glutamic acid (HbA), HbC migrates the slowest toward the positive anode.

Flashcard 378: What are the followings associated with? -Cleavage of DNA strands to remove supercoils -Excision of thymine dimers within DNA -Removal of mismatched base pairs during DNA replication -Removal of RNA primer nucleotides -Unwinding of the 2 strands of template DNA (DNA polymerase 1, DNA gyrase, UV-specific endonuclease, helicase)

Answer: Cleavage of DNA strands to remove supercoils: DNA gyrase (topoisomerase 2) -Excision of thymine dimers within DNA: UV-specific endonuclease. -Removal of mismatched base pairs during DNA replication: DNA polymerase 3 (most common), DNA pol 1, DNA pol 2. -Removal of RNA primer nucleotides: DNA polymerase 1 -Unwinding of the 2 strands of template DNA: Helicase

Flashcard 379: 34 y/o woman comes for breast examination. -Screening test was performed using Polymerase chain reaction (PCR) to amplify the target of exon. -Gel electrophoresis to assess the size of the exon compared to the wild type allele.What features must be known in order to perform the amplification part of this analysis?

Answer: The nucleotide sequence of the DNA regions flanking the target exon (required for primer synthesis).

Flashcard 380: An infant appears healthy at birth but develops transfusion-dependent hemolytic anemia by age 6 months. - His erythrocytes contain insoluble aggregates of hemoglobin subunits. - The child developed normally in utero because at that time he produced high quantities of:

Answer: Gamma-globin (γ-globin)