Passage
A 6-day-old, genotypically normal (46,XX) female patient shows symptoms of hypoglycemia (low blood glucose) and hypotonia (decreased muscle tone). Physical examination reveals abnormal development of the external genitalia, and laboratory studies show elevated urinary sodium content, increased serum levels of potassium, and abnormal serum concentration of several steroid hormones. The patient is diagnosed with 21-hydroxylase deficiency, the most common type of congenital adrenal hyperplasia (CAH).CAH refers to a group of autosomal recessive diseases, each associated with defective production of one or more steroid hormones by the adrenal glands, two crescent-shaped glands located above each kidney in the abdominal cavity. It has been reported that unequal crossing over involving chromosome 6 can result in CAH. More than 90% of CAH diagnoses are associated with a deficiency of 21-hydroxylase, an enzyme encoded by the CYP21A2 gene on chromosome 6.Normally, 21-hydroxylase catalyzes chemical reactions involved in the synthesis of aldosterone and cortisol, the principal mineralocorticoid and glucocorticoid hormones, respectively. As a result, patients with 21-hydroxylase deficiency exhibit diminished serum levels of aldosterone and cortisol. However, synthesis and secretion of the sex hormone testosterone is excessive. Glucocorticoid deficiency disrupts the negative feedback loop linking the brain to the adrenal gland, leading to hyperplasia (increased cell proliferation) of adrenal tissue.The patient's 21-hydroxylase deficiency is treated with regular administration of synthetic steroid hormones. Her condition improves after receiving these medications.
-Patients with CAH exhibit hypoglycemia due to numerous endocrine abnormalities. In healthy individuals, hypoglycemia will trigger an increase in the serum level of:insulin.epinephrine.glucagon.

Question

Passage
A 6-day-old, genotypically normal (46,XX) female patient shows symptoms of hypoglycemia (low blood glucose) and hypotonia (decreased muscle tone).  Physical examination reveals abnormal development of the external genitalia, and laboratory studies show elevated urinary sodium content, increased serum levels of potassium, and abnormal serum concentration of several steroid hormones.  The patient is diagnosed with 21-hydroxylase deficiency, the most common type of congenital adrenal hyperplasia (CAH).CAH refers to a group of autosomal recessive diseases, each associated with defective production of one or more steroid hormones by the adrenal glands, two crescent-shaped glands located above each kidney in the abdominal cavity.  It has been reported that unequal crossing over involving chromosome 6 can result in CAH.  More than 90% of CAH diagnoses are associated with a deficiency of 21-hydroxylase, an enzyme encoded by the CYP21A2 gene on chromosome 6.Normally, 21-hydroxylase catalyzes chemical reactions involved in the synthesis of aldosterone and cortisol, the principal mineralocorticoid and glucocorticoid hormones, respectively.  As a result, patients with 21-hydroxylase deficiency exhibit diminished serum levels of aldosterone and cortisol.  However, synthesis and secretion of the sex hormone testosterone is excessive.  Glucocorticoid deficiency disrupts the negative feedback loop linking the brain to the adrenal gland, leading to hyperplasia (increased cell proliferation) of adrenal tissue.The patient's 21-hydroxylase deficiency is treated with regular administration of synthetic steroid hormones.  Her condition improves after receiving these medications.
-Patients with CAH exhibit hypoglycemia due to numerous endocrine abnormalities.  In healthy individuals, hypoglycemia will trigger an increase in the serum level of:insulin.epinephrine.glucagon.

Quizplus · Accepted Answer

11ecba2d_0fcd_4ca1_a3bf_657b0c895cae_MD0008_00 Homeostasis is the process by which an organism maintains a relatively stable internal environment in response to external or internal changes. For example, blood pressure, blood pH, and body temperature are all maintained within specific ranges that are optimal for normal bodily function. Failure to achieve homeostasis of one or more parameters can lead to disease and, potentially, death. The serum level of glucose is also subject to homeostatic control primarily through the actions of hormones. When blood glucose levels are low (eg, during periods of fasting), the hormone glucagon is secreted from the alpha cells of the pancreas, and the autonomic nervous system promotes the release of epinephrine and norepinephrine by the adrenal medulla. Glucagon is a peptide hormone that promotes gluceoneogenesis (the synthesis of glucose from other molecules) and glycogenolysis (the breakdown of glycogen into glucose). Epinephrine and norepinephrine also promote glycogenolysis. Therefore, the overall effect of glucagon, epinephrine, and norepinephrine is to promote the synthesis of glucose and its release into the systemic circulation, thereby correcting the low serum level of glucose. According to the passage, symptoms of congential adrenal hyperplasia (CAH) include hypoglycemia (low serum glucose). In healthy individuals, low serum glucose can be expected to increase the release of glucagon, epinephrine, and norepinephrine because these hormones would act to restore serum level of glucose to the normal range (Numbers II and III). (Number I) In response to high serum glucose concentration, the peptide hormone insulin is secreted from the beta cells of the pancreas. Insulin promotes the uptake of glucose by fat, liver, and skeletal muscle cells. Insulin also promotes glycogenesis, the synthesis of the glucose storage molecule glycogen. Overall, insulin decreases blood glucose concentration by promoting the cellular uptake and storage of glucose. Educational objective: Glucose is a key energy source for many tissues in the human body. The serum level of glucose is tightly regulated through the actions of the hormones insulin, glucagon, epinephrine, norepinephrine, and the glucocorticoids.

Passage a 6-Day-Old, Genotypically Normal (46,XX) Female Patient Shows Symptoms of of Hypoglycemia