Absent adrenal gland | |
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This condition indicates absence of a adrenal gland | |
Specialty | Medical genetics |
Absent adrenal gland is a rare condition where the adrenal gland is absent at birth. [1] It should not be confused with adrenal insufficiency or congenital adrenal hyperplasia, where the gland is present but may not be functioning adequately.
Due to the absence of adrenal cortex, the condition causes extreme symptoms of adrenal insufficiency at birth due to very low levels of aldosterone and cortisol. The adrenal medulla can be normally present, poorly formed, or absent, however even so the effects of circulatory catecholamine deficiency are generally mild (due to sympathetic nervous system compensation), except in episodes of hypoglycemia. [2]
SF-1 plays a role in the development of adrenal gland. Single gene polymorphism involving SF-1 gene may have a role in adrenal gland agenesis. [1] Various other factors have also been identified. [3] [4] [5] [6]
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The adrenal glands are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which produces steroid hormones and an inner medulla. The adrenal cortex itself is divided into three main zones: the zona glomerulosa, the zona fasciculata and the zona reticularis.
Adrenocorticotropic hormone is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a medication and diagnostic agent. ACTH is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress. Its principal effects are increased production and release of cortisol and androgens by the cortex and medulla of the adrenal gland, respectively. ACTH is also related to the circadian rhythm in many organisms.
Addison's disease, also known as primary adrenal insufficiency, is a rare long-term endocrine disorder characterized by inadequate production of the steroid hormones cortisol and aldosterone by the two outer layers of the cells of the adrenal glands, causing adrenal insufficiency. Symptoms generally come on slowly and insidiously and may include abdominal pain and gastrointestinal abnormalities, weakness, and weight loss. Darkening of the skin in certain areas may also occur. Under certain circumstances, an adrenal crisis may occur with low blood pressure, vomiting, lower back pain, and loss of consciousness. Mood changes may also occur. Rapid onset of symptoms indicates acute adrenal failure, which is a clinical emergency. An adrenal crisis can be triggered by stress, such as from an injury, surgery, or infection.
Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones. The adrenal glands—also referred to as the adrenal cortex—normally secrete glucocorticoids, mineralocorticoids, and androgens. These hormones are important in regulating blood pressure, electrolytes, and metabolism as a whole. Deficiency of these hormones leads to symptoms ranging from abdominal pain, vomiting, muscle weakness and fatigue, low blood pressure, depression, mood and personality changes to organ failure and shock. Adrenal crisis may occur if a person having adrenal insufficiency experiences stresses, such as an accident, injury, surgery, or severe infection; this is a life-threatening medical condition resulting from severe deficiency of cortisol in the body. Death may quickly follow.
Lipoid congenital adrenal hyperplasia is an endocrine disorder that is an uncommon and potentially lethal form of congenital adrenal hyperplasia (CAH). It arises from defects in the earliest stages of steroid hormone synthesis: the transport of cholesterol into the mitochondria and the conversion of cholesterol to pregnenolone—the first step in the synthesis of all steroid hormones. Lipoid CAH causes mineralocorticoid deficiency in affected infants and children. Male infants are severely undervirilized causing their external genitalia to look feminine. The adrenals are large and filled with lipid globules derived from cholesterol.
Pubarche refers to the first appearance of pubic hair at puberty and it also marks the beginning of puberty. It is one of the physical changes of puberty and can occur independently of complete puberty. The early stage of sexual maturation, also known as adrenarche, is marked by characteristics including the development of pubic hair, axillary hair, adult apocrine body odor, acne, and increased oiliness of hair and skin. The Encyclopedia of Child and Adolescent Health corresponds SMR2 with pubarche, defining it as the development of pubic hair that occurs at a mean age of 11.6 years in females and 12.6 years in males. It further describes that pubarche's physical manifestation is vellus hair over the labia or the base of the penis. See Table 1 for the entirety of the sexual maturity rating description.
Congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) is a genetic disorder characterized by impaired production of cortisol in the adrenal glands.
Optic nerve hypoplasia (ONH) is a medical condition arising from the underdevelopment of the optic nerve(s). This condition is the most common congenital optic nerve anomaly. The optic disc appears abnormally small, because not all the optic nerve axons have developed properly. It is often associated with endocrinopathies, developmental delay, and brain malformations. The optic nerve, which is responsible for transmitting visual signals from the retina to the brain, has approximately 1.2 million nerve fibers in the average person. In those diagnosed with ONH, however, there are noticeably fewer nerves.
Potter sequence is the atypical physical appearance of a baby due to oligohydramnios experienced when in the uterus. It includes clubbed feet, pulmonary hypoplasia and cranial anomalies related to the oligohydramnios. Oligohydramnios is the decrease in amniotic fluid volume sufficient to cause deformations in morphogenesis of the baby.
Adrenocorticotropic hormone deficiency is a rare disorder characterized by secondary adrenal insufficiency with minimal or no cortisol production and normal pituitary hormone secretion apart from ACTH. ACTH deficiency may be congenital or acquired, and its symptoms are clinically similar to those of glucocorticoid deficiency. Symptoms consist of weight loss, diminished appetite, muscle weakness, nausea, vomiting, and hypotension. Low blood sugar and hyponatremia are possible; however, blood potassium levels typically remain normal because affected patients are deficient in glucocorticoids rather than mineralocorticoids because of their intact renin-angiotensin-aldosterone system. ACTH may be undetectable in blood tests, and cortisol is abnormally low. Glucocorticoid replacement therapy is required. With the exception of stressful situations, some patients with mild or nearly asymptomatic disease may not require glucocorticoid replacement therapy. As of 2008 about two hundred cases have been described in the literature.
Congenital absence of the vas deferens (CAVD) is a condition in which the vasa deferentia reproductive organs fail to form properly prior to birth. It may either be unilateral (CUAVD) or bilateral (CBAVD).
Cholesterol side-chain cleavage enzyme is commonly referred to as P450scc, where "scc" is an acronym for side-chain cleavage. P450scc is a mitochondrial enzyme that catalyzes conversion of cholesterol to pregnenolone. This is the first reaction in the process of steroidogenesis in all mammalian tissues that specialize in the production of various steroid hormones.
Steroid 21-hydroxylase is a protein that in humans is encoded by the CYP21A2 gene. The protein is an enzyme that hydroxylates steroids at the C21 position on the molecule. Naming conventions for enzymes are based on the substrate acted upon and the chemical process performed. Biochemically, this enzyme is involved in the biosynthesis of the adrenal gland hormones aldosterone and cortisol, which are important in blood pressure regulation, sodium homeostasis and blood sugar control. The enzyme converts progesterone and 17α-hydroxyprogesterone into 11-deoxycorticosterone and 11-deoxycortisol, respectively, within metabolic pathways which in humans ultimately lead to aldosterone and cortisol creation—deficiency in the enzyme may cause congenital adrenal hyperplasia.
Disorders of sex development (DSDs), also known as differences in sex development, diverse sex development and variations in sex characteristics (VSC), are congenital conditions affecting the reproductive system, in which development of chromosomal, gonadal, or anatomical sex is atypical.
The ACTH test is a medical test usually requested and interpreted by endocrinologists to assess the functioning of the adrenal glands' stress response by measuring the adrenal response to adrenocorticotropic hormone or another corticotropic agent such as tetracosactide or alsactide (Synchrodyn). ACTH is a hormone produced in the anterior pituitary gland that stimulates the adrenal glands to release cortisol, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEA-S), and aldosterone.
The steroidogenic factor 1 (SF-1) protein is a transcription factor involved in sex determination by controlling the activity of genes related to the reproductive glands or gonads and adrenal glands. This protein is encoded by the NR5A1 gene, a member of the nuclear receptor subfamily, located on the long arm of chromosome 9 at position 33.3. It was originally identified as a regulator of genes encoding cytochrome P450 steroid hydroxylases, however, further roles in endocrine function have since been discovered.
DAX1 is a nuclear receptor protein that in humans is encoded by the NR0B1 gene. The NR0B1 gene is located on the short (p) arm of the X chromosome between bands Xp21.3 and Xp21.2, from base pair 30,082,120 to base pair 30,087,136.
Adrenal gland disorders are conditions that interfere with the normal functioning of the adrenal glands. Your body produces too much or too little of one or more hormones when you have an adrenal gland dysfunction. The type of issue you have and the degree to which it affects your body's hormone levels determine the symptoms.
Tracheal agenesis is a rare birth defect with a prevalence of less than 1 in 50,000 in which the trachea fails to develop, resulting in an impaired communication between the larynx and the alveoli of the lungs. Although the defect is normally fatal, occasional cases have been reported of long-term survival following surgical intervention.
Late onset congenital adrenal hyperplasia (LOCAH), also known as nonclassic congenital adrenal hyperplasia, is a milder form of congenital adrenal hyperplasia (CAH), a group of autosomal recessive disorders characterized by impaired cortisol synthesis that leads to variable degrees of postnatal androgen excess.