ASPM Gene

Definition:

ASPM is a human gene whose defective forms are associated with autosomal recessive primary microcephaly."ASPM" is an acronym for "Abnormal Spindle-like, Microcephaly-associated", which reflects its being an ortholog to the Drosophila melanogaster "abnormal spindle" (asp) gene.

Chromsome: Chromosome 1


Location :1q31

Size of gene:62291bp (195319997 to195382287 complementary)

No Exons :28

No Introns:27

Description:The ASPM gene is the human ortholog of the Drosophila melanogaster 'abnormal spindle' gene (asp), which is essential for normal mitotic spindle function in embryonic neuroblasts.

Evolutionary significance:

A new allele (version) of ASPM appeared sometime between 14,100 and 500 years ago with a mean estimate of 5,800 years ago. The new allele has a frequency of about 50 percent in populations of the Middle East and Europe, it is less frequent in East Asia, and has low frequencies among Sub-Saharan African populations.

The mean estimated age of the ASPM allele of 5,800 years ago, roughly correlates with the development of written language, spread of agriculture and development of cities. Currently, two alleles of this gene exist: the older (pre-5,800 years ago) and the newer (post-5,800 years ago). About 10% of humans have two copies of the new ASPM allele, while about 50% have two copies of the old allele. The other 40% of humans have one copy of each. Of those with an instance of the new allele, 50% of them are an identical copy suggesting a highly rapid spread from the original mutation. According to a hypothesis called a "selective sweep", the rapid spread of a mutation (such as the new ASPM) through the population indicates that the mutation is somehow advantageous to the individual. As of today, there is no evidence to support the notion that the new ASPM allele increases intelligence, and some researchers dispute whether the spread of the allele even demonstrates selection. They suggest that the current distribution of the alleles could be explained by a founder effect, following an out of Africa dispersal. However, statistical analysis has shown that the older forms of the gene are found more heavily in populations that speak tonal languages like Chinese.

Protein Sequence:Asp (abnormal spindle)-like, microcephaly associated [Homo sapiens].

ACADM Gene

Defintion:
ACADM (acyl-Coenzyme A dehydrogenase, C-4 to C-12 straight chain) is a gene that provides instructions for making an enzyme called acyl-coenzyme
Chromosome: Chromosome 1

Location: 1p31 (75962870 to 76001771)

Size Of Gene: 38902 bp

Locus :RP4-682C21.1

Number of Exons: 12

Number Of Introns : 11

Description: A dehydrogenase that is important for breaking down (degrading) a certain group of fats called medium-chain fatty acids. These fatty acids are found in foods such as milk and certain oils, and they are also stored in the body's fat tissue. Medium-chain fatty acids are also produced when larger fatty acids are degraded. The acyl-coenzyme A dehydrogenase for medium-chain fatty acids (ACADM) enzyme is essential for converting these particular fatty acids to energy, especially during periods without food (fasting). The ACADM enzyme functions in mitochondria, the energy-producing centers within cells. It is found in the mitochondria of several types of tissues, particularly the liver.

Related conditions

Medium-chain acyl-coenzyme A dehydrogenase deficiency can be caused by mutations in the ACADM gene. More than 30 ACADM gene mutations that cause medium-chain acyl-coenzyme A dehydrogenase deficiency have been identified. Many of these mutations switch an amino acid building block in the ACADM enzyme. The most common amino acid substitution replaces lysine with glutamic acid at position 304 in the enzyme's chain of amino acids (also written as Lys304Glu or K304E). This mutation and other amino acid substitutions alter the enzyme's structure, reducing or abolishing its activity. Other mutations delete or duplicate part of the ACADM gene, which leads to an unstable enzyme that cannot function.

With a shortage (deficiency) of functional ACADM enzyme, medium-chain fatty acids cannot be degraded and processed. As a result, these fats are not converted into energy, which can lead to characteristic symptoms of this disorder, such as lack of energy (lethargy) and low blood sugar. Levels of medium-chain fatty acids or partially degraded fatty acids may build up in tissues and can damage the liver and brain, causing more serious complications.

Protein Coded:NP_000007

"ACADM." Wikipedia, The Free Encyclopedia. 30 Aug 2008, 20:53 UTC. 14 Oct 2008 <http://en.wikipedia.org/w/index.php?title=ACADM&oldid=235248417>.

Carnitine palmitoyltransferase II

Definition
Carnitine palmitoyltransferase II, also known as CPT2, is a human gene also known has CPTASE

Chromosome: Chromosome 1

Position:1p32

Size Of Gene:  17767 bp (53434689..53452455)

No Exons 5

Description

Carnitine palmitoyltransferase II precursor (CPT2) is a nuclear protein which is transported to the mitochondrial inner membrane. CPT2 together with carnitine palmitoyltransferase I oxidizes long-chain fatty acids in the mitochondria. Defects in this gene are associated with mitochondrial long-chain fatty-acid (LCFA) oxidation disorders and carnitine palmitoyltransferase II deficiency.[

Disease:

Carnitine palmitoyltransferase II deficiency is a condition that prevents the body from converting certain fats called long-chain fatty acids into energy, particularly during periods without food (fasting),three main types of carnitine palmitoyltransferase II deficiency are: a lethal neonatal form; a severe infantile form that affects the liver, heart, and muscles (hepatocardiomuscular form); and a less severe form that affects only the muscles (myopathic form). Infants with the lethal neonatal form of this disorder usually experience respiratory failure, liver failure, seizures, and an irregular heart beat (arrythmia) leading to cardiac arrest. In many cases, the brain and kidneys are also abnormal. Usually, affected infants do not survive their first year.

COL11A1 Gene

Definition:

Collagen, type XI, alpha 1, also known as COL11A1, is a human gene.

Chromosome:Chromosome 1

Location: 1p21

Size of gene: 232030 bp (5001..237030)

No Exons:67

Description:

This gene encodes one of the two alpha chains of type XI collagen, a minor fibrillar collagen. Type XI collagen is a heterotrimer but the third alpha chain is a post-translationally modified alpha 1 type II chain. Mutations in this gene are associated with type II Stickler syndrome and with Marshall syndrome. A single-nucleotide polymorphism in this gene is also associated with susceptibility to lumbar disc herniation. Three transcript variants encoding different isoforms have been identified for this gene.

Disease:Stickler syndrome - caused by mutations in the COL11A1 gene

Mutations in the COL11A1 gene have been identified in some people with Stickler syndrome. Some mutations change one of the protein building blocks (amino acids) used to make the pro-alpha1(XI) chain. Other mutations cause segments of DNA to be skipped when the protein is being made, resulting in an abnormally short pro-alpha1(XI) chain. These alterations of type XI collagen impair its function, which can lead hearing loss, a tearing of the lining of the eye (retinal detachment), and abnormalities of the bones and joints.

Mutations in the COL11A1 gene are also responsible for some cases of Marshall syndrome, a disorder that is very similar to Stickler syndrome. In most mutations that cause this syndrome, a segment of DNA is skipped when the protein is made, resulting in an abnormally small pro-alpha1(XI) chain. This shortened protein hinders the formation of mature type XI collagen, which results in the features of Marshall syndrome. Whether Marshall syndrome represents a variant form of Stickler syndrome or a separate disorder is controversial.



Protein:

1464 amino acids. The a1 (I) chains of the type I collagen are synthesised as procollagen molecules containing amino and carboxy-terminal propeptides, wich are removed by site-specific endopeptidase. The central triple helical domain is formed by 338 repeats of a Gly-X-Y triplet where X and Y are often a proline.

Type I collagen is the most abundant protein in vertebrates and a constituent of the extra cellular matrix in connective tissue of bone, skin, tendon, ligament and dentine. It is mostly produced and secreted by fibroblasts and osteoblasts.

USH2A gene

The official name of USH2A gene is Usher syndrome 2A (autosomal recessive, mild)..The USH2A gene provides instructions for making anan enzyme called usherin. Usherin is an important component of basement membranes, which are thin sheet-like structures that separate and support cells in many tissues. Usherin is found in the inner ear and the part of the eye that detects light and color (the retina). Although the function of usherin has not been well established, studies suggest that this protein is part of a larger protein complex that plays an important role in inner ear and retinal development. In these locations, the protein complex may also be involved in the function of synapses, which are junctions between nerve cells where cell-to-cell communication occurs.

Location:

USH2A gene is present in human chromosome 1 and ts coded from region 213,862,858 to 214,663,360 complement with 71 exons, the cytogenetic location 1q41.

Disease

Mutations in USH2A gene causes a form of  Usher syndrome type IIA,Usher syndrome is a condition characterized by hearing loss or deafness and progressive vision loss. The loss of vision is caused by an eye disease called retinitis pigmentosa (RP), which affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss occurs as the light-sensing cells of the retina gradually deteriorate.Mutations change single protein building blocks (amino acids) in the usherin protein. In some cases, these mutations lead to the production of an abnormally short version of the protein or prevent the cell from making any functional usherin. Other mutations insert or delete small amounts of DNA in the USH2A gene, which probably impairs the normal function of usherin. Researchers have not determined how a missing or altered usherin protein leads to the signs and symptoms of Usher syndrome.The most common mutation in the USH2A gene is found in about 25 percent of people with Usher syndrome type IIA, particularly those from Europe, the United States, South Africa, and China. This mutation deletes a specific DNA building block, a guanine (G) nucleotide, at position 2299 in the USH2A gene (written as 2299delG). Individuals with this change, or with similar mutations in the USH2A gene, develop moderate to severe hearing loss and retinitis pigmentosa, a disorder that results in loss of vision.

UROD Gene

The official name of UROD gene is uroporphyrinogen decarboxylase.The UROD gene provides instructions for making anan enzyme called uroporphyrinogen decarboxylase. Uroporphyrinogen III decarboxylase (UroD) is a homodimeric enzyme which catalyzes the fifth step in heme biosynthesis: the elimination of carboxyl groups from the four acetate side chains of uroporphyrinogen III to yield coproporphyrinogen III.Three additional enzymes modify this product before it becomes heme. The heme molecule is then incorporated into hemoglobin and packaged into red blood cells, or it is used in the liver for the production of certain liver enzymes.

Location:

UROD gene is present in human chromosome 1 and ts coded from region 45250417 to 45253928 with 10 exons, the cytogenetic location 1p34.

Disease

Mutations in UROD gene causes a form of porphyria called porphyria cutanea tarda and hepatoerythropoietic porphyria,In porphyria cutanea tarda the mutations occur in one of the two copies of the UROD gene in each cell, which usually reduces the activity of uroporphyrinogen decarboxylase by 50 percent throughout the body.As a result, byproducts of heme production called porphyrins build up in the body, particularly in the liver. This buildup, in combination with nongenetic factors (such as alcohol, smoking, certain hormones, excess iron, and viral infections), causes this type of porphyria.

In hepatoerythropoietic porphyria Most of the mutations are unique in this type of porphyria and have not been found in porphyria cutanea tarda. Mutations that cause hepatoerythropoietic porphyria occur in both copies of the UROD gene in each cell, which reduces the activity of uroporphyrinogen decarboxylase to less than 10 percent of normal. Extremely low levels of this enzyme prevent sufficient amounts of heme from being produced. As a result, byproducts of heme production called porphyrins build up in the body, causing this type of porphyria.