A 7-year-old boy is brought to the emergency department because of high-grade fever and lethargy for 4 days. He has had a severe headache for 3 days and 2 episodes of non-bilious vomiting. He has sickle cell disease. His only medication is hydroxyurea. His mother has refused vaccinations and antibiotics in the past because of their possible side effects. He appears ill. His temperature is 40.1°C (104.2°F), pulse is 131/min, and blood pressure is 92/50 mm Hg. Examination shows nuchal rigidity. Kernig and Brudzinski signs are present. A lumbar puncture is performed. Analysis of the cerebrospinal fluid (CSF) shows a decreased glucose concentration, increased protein concentration, and numerous segmented neutrophils. A Gram stain of the CSF shows gram-negative coccobacilli. This patient is at greatest risk for which of the following complications?
AAdrenal insufficiency
BCerebral palsy
CHearing loss
DCommunicating hydrocephalus
EBrain abscess
An 18-year-old African-American woman comes to the physician for the evaluation of worsening fatigue that started 1 year ago. Physical examination shows mild jaundice and splenomegaly. Laboratory studies show: Hemoglobin 10.4 g/dL Mean corpuscular hemoglobin concentration 43% Hb/cell Platelet count 220,000/mm3 Reticulocyte count 7% A peripheral blood smear shows target cells and erythrocytes with hemoglobin crystals. Which of the following is the most likely underlying cause of this patient's findings?
AAcquired mutation of membrane-bound glycosylphosphatidylinositol anchor
BDecreased conversion of oxidized glutathione into its reduced form
CReplacement of glutamate by valine in beta-globin chain
DReplacement of glutamate by lysine in beta-globin chain
EReduced production of beta-globin due to a mutation in the HbB gene
A clinical trial is being run with patients that have a genetic condition characterized by abnormal hemoglobin that can undergo polymerization when exposed to hypoxia, acidosis, or dehydration. This process of polymerization is responsible for the distortion of the red blood cell (RBC) that acquires a crescent shape and the hemolysis of RBCs. Researchers are studying the mechanisms of the complications commonly observed in these patients such as stroke, aplastic crisis, and auto-splenectomy. What kind of mutation leads to the development of the disease?
ASilent mutation
BSplice site
CMissense mutation
DNonsense mutation
EFrameshift mutation
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