Albright's Hereditary Osteodystrophy
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Albright's hereditary osteodystrophy is a form of
osteodystrophy Osteodystrophy is any dystrophic growth of the bone. It is defective bone development that is usually attributable to renal disease or to disturbances in calcium and phosphorus metabolism. One form is renal osteodystrophy. See also * List of ...
, and is classified as the
phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
of
pseudohypoparathyroidism Pseudohypoparathyroidism is a condition associated primarily with resistance to the parathyroid hormone. Those with the condition have a low serum calcium and high phosphate, but the parathyroid hormone level (PTH) is appropriately high (due to th ...
type 1A; this is a condition in which the body does not respond to
parathyroid hormone Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine. PTH influences bone re ...
.


Signs and symptoms

The disorder is characterized by the following: *
Hypogonadism Hypogonadism means diminished functional activity of the gonads—the testes or the ovaries—that may result in diminished production of sex hormones. Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estrogen ...
*
Brachydactyly Brachydactyly (Greek βραχύς = "short" plus δάκτυλος = "finger"), is a medical term which literally means "short finger". The shortness is relative to the length of other long bones and other parts of the body. Brachydactyly is an in ...
syndrome *
Choroid plexus The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central nerv ...
calcification * Hypoplasia of dental enamel * Full
cheeks The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the insi ...
* Hypocalcemic tetany Individuals with Albright hereditary osteodystrophy exhibit
short stature Short stature refers to a height of a human which is below typical. Whether a person is considered short depends on the context. Because of the lack of preciseness, there is often disagreement about the degree of shortness that should be called '' ...
, characteristically shortened fourth and fifth
metacarpal In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...
s, rounded
facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formatio ...
, and often mild intellectual deficiency. Albright hereditary osteodystrophy is commonly known as pseudohypoparathyroidism because the kidney responds as if parathyroid hormone were absent. Blood levels of parathyroid hormone are elevated in pseudohypoparathyroidism due to the hypocalcemia


Genetics

This condition is associated with genetic imprinting. It is thought to be inherited in an
autosomal An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in au ...
dominant pattern, and seems to be associated with a
Gs alpha subunit The Gs alpha subunit (Gαs, Gsα) is a subunit of the heterotrimeric G protein Gs that stimulates the cAMP-dependent pathway by activating adenylyl cyclase. Gsα is a GTPase that functions as a cellular signaling protein. Gsα is the founding me ...
deficiency.


Mechanism

The mechanism of this condition is due to Gs signaling decrease in hormones having to do with
signal transduction Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events, most commonly protein phosphorylation catalyzed by protein kinases, which ultimately results in a cellula ...
which is when a signal from outside cell causes change within the cell (in function).
Renal tubule The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure ca ...
cells only express maternal
alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...
(variant form of a gene).


Diagnosis

The diagnosis of Albright's hereditary osteodystrophy is based on the following exams below: * clicical features * serum calicum, phosphorus, PTH *
Urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...
test for
cAMP Camp may refer to: Outdoor accommodation and recreation * Campsite or campground, a recreational outdoor sleeping and eating site * a temporary settlement for nomads * Camp, a term used in New England, Northern Ontario and New Brunswick to descri ...
and phosphorus


Treatment

Treatment consists of maintaining normal levels of calcium, phosphorus, and vitamin D. Phosphate binders, supplementary calcium and vitamin D will be used as required.


History

The disorder bears the name of
Fuller Albright Fuller Albright (January 12, 1900 – December 8, 1969) was an American endocrinologist who made numerous contributions to his field, especially to the area of calcium metabolism. Albright made great strides and contributions to the understanding ...
, who characterized it in 1942. He was also responsible for naming it "Sebright bantam syndrome," after the
Sebright bantam The Sebright (IPA: ) is a British breed of bantam chicken. It is a true bantam – a miniature bird with no corresponding large version – and is one of the oldest recorded British bantam breeds. It is named after Sir John Saunders Sebrig ...
chicken, which demonstrates an analogous hormone insensitivity. Much less commonly, the term Martin-Albright syndrome is used, this refers to Eric Martin.D. Martin, J. Bourdillon. Un cas de tétanie idiopathique chronique. Échec thérapeutique de la graffe d’un adénome parathyroïdien. Revue médicale de la Suisse romande, Lausanne, 1940, 60: 1166-1177.


See also

*
Pseudopseudohypoparathyroidism Pseudopseudohypoparathyroidism (PPHP) is an inherited disorder, named for its similarity to pseudohypoparathyroidism in presentation. It is more properly Albright hereditary osteodystrophy although without resistance of parathyroid hormone as fr ...


References


Further reading

* *


External links

{{Osteochondropathy Autosomal dominant disorders Genodermatoses Rare diseases