UWorld Exam 1 Section 4 Flashcards
What are clinical features and genetic cause of Angelman syndrome
Caused by maternal microdeletion of 15q11-13 on maternal allele
Presents as inappropriate laughter, seizures, ataxia, and severe intellectual disability
What are the HLA subtypes associated with celiac disease?
HLA DQ2 and HLA DQ8
Think: I ate (8) too (2) much gluten at DQ
Calluses of the skin are formed by which layer of the skin?
Thickening and hardening of the most superficial skin later - stratum corneum
What is the defective enzyme in Lesch-Nyhan syndrome
Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
What is the protein responsible for differentiation of pluripotent cells as well as de-differentiation from a terminally differentiated cell back into a less specialized form?
Transcription factors
- They bind specific DNA sequences and promote or block the recruitement of RNA polymerase to specific genes
- All nucleated cell possess the entire genome, but tissue-specific transcription facotrs allow for only the expression of genes that are relevant for a particular cell type
Where is gastrin produced and what is its function
Produced by G-cells of the antrum of the (lowest part of stomach) in response to decreased HCl
Where are parietal cells located and what do they produce?
Located in the body of the stomach and secrete HCl and IF
Where are chief cells located and what do they produce
Located in the body of the stomach
Produce pepsinogen (which is cleaved to pepsin by HCl produced by the parietal cells)
Describe the “nutcracker” effect
Increased pressure within the L renal vein due to it’s compression between the aorta and the superior mesenteric artery
This increased pressure may result in increased pressure within the L gonadal vein, resulting in valve leaflet failure and retrograde blood flow, leading to L sided testicular varicocele
Varicocele worsens with standing and decreases in size with laying down because blood can return to systemic circulation
What is the malignancy commonly associated with acanthosis nigracans, especially sudden appearance and rapid spread?
Gastric carcinoma
What is the clinical presentation of Peutz-Jeghers syndrome and what are associated complications?
Numerous hamartomas throughout the GI tract, hyperpigmentation of mouth, lips, hands, and genitalia
Associated with increased risk of breast and GI cancer
What is the mechanism of action of Leuprolide
GnRH agonist (antagonist properties when given continuously - will decreased LH and FSH)
What are the cardiac abnormalities found in DiGeorge?
Persistent truncus arteriosus, tetralogy of Fallot, interrupted aortic arch
What disease is indicated by absence of CD40 ligand
Hyper-IgM syndrome
B cells (CD40 receptor) cannot bind to CD4+ cells (CD40 ligand) in order to undergo class-switching
What nucleotide sequence is preferentially methylated and found in the promoter regions of silent genes?
Cytosine-guanine dinucleotide repeats
What is the enzyme deficiency in Fabry disease?
alpha-galactosidase A
Think: Fabio is the alpha male
What are the defining features of Gaucher disease
Hepatosplenomegaly, Pancytopenia, Osteoporosis
Gaucher cell with “crumpled tissue paper” appearance
What organism forms conida in radiating chains at the end of a conidiophore (“broom-like” apperance)
Aspergillus fumigatus
What is it called when bacteria directly take up naked DNA from the environment?
Transformation
What is it called when there is a one way transfer of DNA from one bacteria to the other with the donor cell using F factor DNA to code for a sex pilus
Conjugation
Think: conjugation = consumation
What is it called when bacteria transfer DNA to another bacteria via a bacteriophage
Transduction
Think: transduction = signal (there is a signal being sent in this method vs. transformation where there is no signal and free DNA is just picked up from the environment)
