Definition of Amyotrophic lateral sclerosis 8

Amyotrophic lateral sclerosis 8: ALS8. A form of amyotrophic lateral sclerosis (ALS) inherited in an autosomal dominant manner due to mutation in a gene on chromosome 20ptel.

Definition of Amyotrophic lateral sclerosis 7

Amyotrophic lateral sclerosis 7: ALS7. A form of amyotrophic lateral sclerosis (ALS) inherited in an autosomal dominant manner due to mutation in a gene on chromosome 20ptel.

Definition of Amyotrophic lateral sclerosis 1

Amyotrophic lateral sclerosis 1: ALS1. A form of amyotrophic lateral sclerosis (ALS) inherited in an autosomal dominant manner and caused by mutation in the superoxide dismutase-1 gene (SOD1) on chromosome 21q22.1. About 15 to 20% of familial ALS is type 1 (ALS1). Sporadic cases of ALS are sometimes due to new mutation in the SOD1 gene.

Definition of Allele

Allele: An alternative form of a gene. One of the different forms of a gene that can exist at a single locus (spot on a chromosome). Also one of the different forms of any segment of a chromosome.

Definition of ALCAM

ALCAM: A receptor expressed on T cells which
is involved in the adhesion of cells. ALCAM stands for activated leukocyte cell adhesion molecule. The gene encoding ALCAM is on chromosome 3 in region 3q13.1-q13.2. The ALCAM gene has been reported to be less active in breast tumors with a poor prognosis.

Definition of Aicardi syndrome

Aicardi syndrome: A genetic disorder characterized by the partial or complete agenesis of the corpus callosum (the structure that links the 2 hemispheres of the brain), infantile spasms (a characteristic form of childhood seizures), mental retardation, and an ocular (eye) abnormality called chorioretinal lacunae in which there are lacunae (holes) in the retina of the eye.
Aicardi syndrome may be associated with other brain defects such as microcephaly (small brain) or porencephalic cysts (cerebrospinal fluid-filled cavities or gaps in the brain). Features associated with Aicardi syndrome include cleft lip and/or palate, fatty tumors (lipomas) of the scalp, blood vessel malformations (cavernous hemangiomas), rib and vertebral defects and scoliosis (curved spine).
The genetics of Aicardi syndrome are extraordinary. The disorder affects only females. It is an X-linked dominant trait lethal in males. In a hemizygous male (whose only X chromosome contains the Aicardi gene), the Aicardi gene is fatal before birth. In a heterozygous female (with the Aicardi gene on one of her two X chromosomes), the Aicardi gene causes Aicardi syndrome. The Aicardi gene has been charted to the short (p) arm of the X chromosome and is in band Xp22.
There is no cure for Aicardi syndrome. Nor is there a standard course of treatment. Treatment is purely symptomatic. It generally involves management of seizures and programs for the mental retardation.
The prognosis for individuals with Aicardi syndrome varies according to the presence and severity of symptoms.

Definition of Aging

Aging: The process of becoming older, a process that is genetically determined and environmentally modulated.
Research into aging: To sum up the state of research into aging is well beyond the confines of this space (and this writer's talents). However, here is one type of research into the genetics of aging.
A gene has been discovered that helps determine the life-span of the fruit fly Drosophila. When the gene is mutated (altered), it can extend the life-span of fruit flies. It doubles their life-span. The gene has been named Indy (for I'm not dead yet). It appears that the protein encoded by this gene transports and recycles metabolic byproducts. Defects in the gene may lead to production of a protein that renders metabolism less efficient so that its body functions as if the fruit fly were dieting, even though its eating habits are unchanged. Mutations in Indy thus appear to create a metabolic state that mimics caloric restriction, which has been shown to extend life-span.
Reference: Rogina B, Reenan RA, Nilsen SP, and Helfand SL. Extended life-span conferred by cotransporter gene mutations in Drosophila. Science Dec 15 2000: 2137-2140.
Some useful suggestions for extending life: No known substance can halt aging or extend life, but here are some useful tips for improving the chances of living a long time and staying healthy:

Eat a balanced diet, including five helpings of fruits and vegetables a day.
Exercise regularly (check with a doctor before starting an exercise program).
Get regular health check-ups.
Don't smoke (it's never too late to quit).
Practice safety habits at home to prevent falls and fractures.
Always wear your seatbelt in a car.
Stay in contact with family and friends.
Stay active through work, play, and community.
Avoid overexposure to the sun and the cold.
If you drink, moderation is the key.
When you drink, let someone else drive.
Keep personal and financial records in order to simplify budgeting and investing.
Plan long-term housing and money needs.
Keep a positive attitude toward life.
Do things that make you happy.

Achondroplasia: The most common form of short stature with disproportionately short limbs -- dwarfism with short arms and legs. Achondroplasia is caused by mutation in the fibroblast growth factor receptor-3 gene (FGFR3), which is located on chromosome 4 in chromosome band 4p16.3.
Aside from short arms and legs, the fingers are short and the
ring and middle fingers diverge giving the hand a trident (three-
pronged) appearance. There is a typically large head with prominence of the forehead (frontal bossing), underdevelopment (hypoplasia) of the midface with cheekbones that lack prominence, and a low nasal bridge with narrow nasal passages. The brain is normal and intelligence is entirely normal in achondroplasia. However, the complications of achondroplasia can impinge on the brain and the spinal cord.
Achondroplasia is inherited as an autosomal dominant trait
affecting boys and girls equally. The parents of children with
achondroplasia are more often than not normal. Most cases of
achondroplasia are due to new mutations that appear for the first
time in the affected children.
Achondroplasia can be diagnosed before birth by molecular means.
The limited number of changes in the FGF3 gene responsible for achondroplasia and the ease with which they can be detected provide the basis for a simple method for prenatal diagnosis.

Definition of Aarskog-Scott syndrome

Aarskog-Scott syndrome: A syndrome of wide spaced eyes (ocular hypertelorism), front-facing (anteverted) nostrils, a broad upper lip, a malformed ("saddle-bag") scrotum, and laxity of the ligaments resulting in bending back of the knees (genu recurvatum), flat feet, and overly extensible fingers. There are X-linked and autosomal forms of the disease. The gene for the X-linked form has been mapped to chromosome band Xp11.21 and identified as the FGD1 gene.
The disease is named for DJ Aarskog (1928-) and CI Scott, Jr. (1934-), Norwegian and American pediatricians, who described it in 1970 and 1971. It is also known as Aarskog syndrome, faciodigitogenital dysplasia, and faciogenital dysplasia.