Browsing Pathways

Methylhistidine is a modified amino acid that is produced in myocytes during the methylation of actin and myosin. It is also formed from the methylation of L-histidine, which takes the methyl group from S-adenosylmethionine and forms S-adenosylhomocysteine as a byproduct. After its formation in the myocytes, methylhistidine enters the blood stream and travels to the kidneys, where it is excreted in the urine. Methylhistidine is present in the blood and urine in higher concentrations after skeletal muscle protein breakdown, which can occur due to disease or injury. Because of this, it can be used to judge how much muscle breakdown is occurring. Methylhistidine levels are also affected by diet, and may differ between vegetarian diets and those containing meats.

11-beta-Hydroxylase Deficiency, also called congenital adrenal hyperplasia (CAH), is an autosomal recessive disorder and caused by a defective 11-beta-hydroxylase. 11-beta-hydroxylase catalyzes the conversion of cortexolone into cortisol which is useful for maintaining blood sugar levels and suppressing inflammation. This disorder is characterized by a large accumulation of cortexolone in the endoplasmic reticulum (ER). Symptoms of the disorder include abnormality of hair growth rate and menstrual cycle. It is estimated that 11-beta-hydroxylase deficiency affects 1 in 100,000 to 200,000 newborns.

11-beta-Hydroxylase Deficiency, also called congenital adrenal hyperplasia (CAH), is an autosomal recessive disorder and caused by a defective 11-beta-hydroxylase. 11-beta-hydroxylase catalyzes the conversion of cortexolone into cortisol which is useful for maintaining blood sugar levels and suppressing inflammation. This disorder is characterized by a large accumulation of cortexolone in the endoplasmic reticulum (ER). Symptoms of the disorder include abnormality of hair growth rate and menstrual cycle. It is estimated that 11-beta-hydroxylase deficiency affects 1 in 100,000 to 200,000 newborns.

17-alpha-hydroxylase deficiency, also known as congenital adrenal hyperplasia (CAH) due to 17-alpha-hydroxylase deficiency or congenital adrenal hyperplasia type 5, is a rare inborn error of metabolism (IEM) and autosomal recessive disorder of the steroidogenesis pathway. It is caused by a mutation in the CYP17A1 gene which encodes the enzyme steroid 17-alpha-hydroxylase. This enzyme hydroxylates both progesterone and pregnenolone into 17-hydroxyprogesterone and 17a-hydroxypregnenolone respectively in the mitochondria, as well as hydroxylating 21-deoxycortisol to 11b-hydroxyprogesterone within the endoplasmic reticulum. When mutated, it leads to an accumulation of pregnenolone, progesterone, deoxycorticosterone and 11-dehydrocorticosterone throughout the cell. 17-alpha hydroxylase deficiency is characterized by a deficiency of sex steroids, as well as glucocorticoids. Symptoms include male undervirilization, as well as lack of development during puberty including amenorrhea for females. Low levels of potassium in the blood due to the increased levels of mineralocorticoids can occur, as well as hypertension. Treatment with dexamethasone has been able to normalize blood pressure and blood potassium levels. It is estimated that 17-alpha-hydroxylase deficiency affects 1 in 1,000,000 individuals.

17-beta hydroxysteroid dehydrogenase III deficiency, also known as 17-KSR deficiency or male pseudohermaphroditism with gynecomastia (MPH), is as rare inborn error of metabolism (IEM) and autosomal recessive disorder of the androgen and estrogen metabolism pathway. It is caused by a mutation in the HSD17B3 gene, which encodes the enzyme testosterone 17-beta-dehydrogenase 3, which is responsible for catalyzing the reversible formation of androstenedione from testosterone. This leads to an accumulation of androstenedione and dehydroepiandrosterone in the body, as well as a lack of testosterone produced. 17-KSR deficiency is characterized by an absence of testosterone in the testis until puberty, where testosterone is produced outside of the gonads. Symptoms include infertility and external female genitalia until puberty, when secondary male sex characteristics occur, as well as gynecomastia. Due to this, many individuals with this disorder are raised as female despite being genetically male, until puberty. Treatment can include removal of testes before puberty, preventing any masculinization at puberty, as well as surgical treatment of genitalia. However, there is no known treatment for restoring the fertility of affected individuals. It is estimated that 17-KSR deficiency affects 1 in 150,000 individuals in The Netherlands, without much information for the rest of the world.

17-beta hydroxysteroid dehydrogenase III deficiency, also known as 17-KSR deficiency or male pseudohermaphroditism with gynecomastia (MPH), is as rare inborn error of metabolism (IEM) and autosomal recessive disorder of the androgen and estrogen metabolism pathway. It is caused by a mutation in the HSD17B3 gene, which encodes the enzyme testosterone 17-beta-dehydrogenase 3, which is responsible for catalyzing the reversible formation of androstenedione from testosterone. This leads to an accumulation of androstenedione and dehydroepiandrosterone in the body, as well as a lack of testosterone produced. 17-KSR deficiency is characterized by an absence of testosterone in the testis until puberty, where testosterone is produced outside of the gonads. Symptoms include infertility and external female genitalia until puberty, when secondary male sex characteristics occur, as well as gynecomastia. Due to this, many individuals with this disorder are raised as female despite being genetically male, until puberty. Treatment can include removal of testes before puberty, preventing any masculinization at puberty, as well as surgical treatment of genitalia. However, there is no known treatment for restoring the fertility of affected individuals. It is estimated that 17-KSR deficiency affects 1 in 150,000 individuals in The Netherlands, without much information for the rest of the world.