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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 the low level of calcium in the blood). Its pathogenesis has been linked to dysfunctional G Proteins (in particular, Gs alpha subunit). Pseudohypoparathyroidism is a very rare disorder, with estimated prevalence between 0.3 and 1.1 cases per 100000 population depending on geographic location. Types Types include: ;Type 1a : Has a characteristic phenotypic appearance (Albright's hereditary osteodystrophy), including short fourth and fifth metacarpals and a rounded facies. It is most likely an autosomal dominant disorder. It is also associated with thyroid stimulating hormone resistance. Caused by GNAS1 mutation. ; Type 1b : Lacks the physical appearance of type 1a, but is biochemically similar. It is associated with a methylation defect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 frequently seen in that affliction. The term Pseudopseudohypoparathyroidism is used to describe a condition where the individual has the phenotypic appearance of Pseudohypoparathyroidism type 1a, but has (unexpected for the phenotype) normal labs including calcium and PTH. It can be considered a variant of Albright hereditary osteodystrophy, or Pseudohypoparathyroidism type 1A, as they present with the same constellation of signs and symptoms, including short stature, brachydactyly, subcutaneous calcification, and obesity. Presentation Pseudopseudohypoparathyroidism can be best understood by comparing it to other conditions: Hormone resistance is not present in Pseudopseudohypoparathyroidism. Short stature may be present. Obesity is less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albright's Hereditary Osteodystrophy
Albright's hereditary osteodystrophy is a form of osteodystrophy, and is classified as the phenotype of pseudohypoparathyroidism type 1A; this is a condition in which the body does not respond to parathyroid hormone. Signs and symptoms The disorder is characterized by the following: * Hypogonadism * Brachydactyly syndrome * Choroid plexus calcification * Hypoplasia of dental enamel * Full cheeks * Hypocalcemic tetany Individuals with Albright hereditary osteodystrophy exhibit short stature, characteristically shortened fourth and fifth metacarpals, rounded facies, 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 dominant pattern, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNAS1
GNAS complex locus is a gene locus in humans. Its main product is the heterotrimeric G-protein alpha subunit Gs-α, a key component of G protein-coupled receptor-regulated adenylyl cyclase signal transduction pathways. GNAS stands for Guanine Nucleotide binding protein, Alpha Stimulating activity polypeptide. Gene This gene locus has a highly complex imprinted expression pattern. It gives rise to maternally-, paternally- and biallelically-expressed transcripts that are derived from four alternative promoters with distinct 5' exons. Some transcripts contain a differentially methylated region (DMR) within their 5' exons; such DMRs are commonly found in imprinted genes and correlate with transcript expression. An antisense transcript also exists, and this antisense transcript and one of the sense transcripts are paternally expressed, produce non-coding RNAs and may regulate imprinting in this region. In addition, one of the transcripts contains a second frame-shifted open re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 remodeling, which is an ongoing process in which bone tissue is alternately resorbed and rebuilt over time. PTH is secreted in response to low blood serum calcium (Ca2+) levels. PTH indirectly stimulates osteoclast activity within the bone matrix (osteon), in an effort to release more ionic calcium (Ca2+) into the blood to elevate a low serum calcium level. The bones act as a (metaphorical) "bank of calcium" from which the body can make "withdrawals" as needed to keep the amount of calcium in the blood at appropriate levels despite the ever-present challenges of metabolism, stress, and nutritional variations. PTH is "a key that unlocks the bank vault" to remove the calcium. PTH is secreted primarily by the chief cells of the parathyroi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacarpals
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeleton, 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 are analogous to the metatarsal bones in the foot. Structure The metacarpals form a transverse arch to which the rigid row of distal carpal bones are fixed. The peripheral metacarpals (those of the thumb and little finger) form the sides of the cup of the palmar gutter and as they are brought together they deepen this concavity. The index metacarpal is the most firmly fixed, while the thumb metacarpal articulates with the trapezium and acts independently from the others. The middle metacarpals are tightly united to the carpus by intrinsic interlocking bone elements at their bases. The ring metacarpal is somewhat more mobile while the fifth metacarpal is semi-independent.Tubiana ''et al'' 1998, p 11 Each metacarpal bone consists o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STX16
Syntaxin-16 is a protein that in humans is encoded by the ''STX16'' gene. It has been associated with pseudohypoparathyroidism type Ib. Losing this gene causes loss of methylation at GNAS1 exon A/B. Interactions STX16 has been shown to interact with VAMP4 Vesicle-associated membrane protein 4 is a protein that in humans is encoded by the ''VAMP4'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein SNAP25 are the main components of a protein complex inv .... References Further reading * * * * * * * {{protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 are analogous to the metatarsal bones in the foot. Structure The metacarpals form a transverse arch to which the rigid row of distal carpal bones are fixed. The peripheral metacarpals (those of the thumb and little finger) form the sides of the cup of the palmar gutter and as they are brought together they deepen this concavity. The index metacarpal is the most firmly fixed, while the thumb metacarpal articulates with the trapezium and acts independently from the others. The middle metacarpals are tightly united to the carpus by intrinsic interlocking bone elements at their bases. The ring metacarpal is somewhat more mobile while the fifth metacarpal is semi-independent.Tubiana ''et al'' 1998, p 11 Each metacarpal bone consists of a bod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archibald's Sign
Archibald's sign (also known as Archibald's metacarpal sign) refers to a feature in the hand characterized by a shortening of the fourth or/and fifth metacarpals when the fist is clenched. Causes The causes of Archibald's sign are not known; however, it has been discovered that it occurs more often in populations with certain disorders. Archibald's sign appears to be more common in individuals who have Turners syndrome. It also seems to be more commonly found in pseudohypoparathyroidism of Albright's hereditary osteodystrophy, brachydactyly, acrodysostosis, and occasionally with homocystinuria. See also *Pseudohypoparathyroidism References External links Archibald's metacarpal sign* An image of an individual with Archibald's sign is shown on the left hand in photo b ithis picture Congenital disorders {{med-sign-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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