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Addison–Schilder Syndrome
Adrenoleukodystrophy (ALD) is a disease linked to the X chromosome. It is a result of fatty acid buildup caused by failure of peroxisomal fatty acid beta oxidation which results in the accumulation of very long chain fatty acids in tissues throughout the body. The most severely affected tissues are the myelin in the central nervous system, the adrenal cortex, and the Leydig cells in the testes. The long chain fatty acid buildup causes damage to the myelin sheath of the neurons of the brain, resulting in seizures and hyperactivity. Other symptoms include problems in speaking, listening, and understanding verbal instructions. Clinically, ALD presents as a heterogeneous disorder, showing several distinct phenotypes, and no clear pattern of genotype–phenotype correlation. As an X-linked disorder, ALD presents more frequently and severely in males; however, approximately 80% of heterozygote females show some symptoms later in life. Approximately one third of male ALD patients wil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neonatal Adrenoleukodystrophy
In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of other organisms. A newborn is, in colloquial use, a baby who is only hours, days, or weeks old; while in medical contexts, a newborn or neonate (from Latin, ''neonatus'', newborn) is an infant in the first 28 days after birth (the term applies to premature, full term, and postmature infants). Infants born prior to 37 weeks of gestation are called "premature", those born between 39 and 40 weeks are "full term", those born through 41 weeks are "late term", and anything beyond 42 weeks is considered "post term". Before birth, the offspring is called a fetus. The term ''infant'' is typically applied to very young children under one year of age; however, definitions may vary and may include children up to two years of age. When a human child ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygote
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperactivity
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple contexts, and developmentally inappropriate. ADHD symptoms arise from executive dysfunction. Impairments resulting from deficits in self-regulation such as time management, inhibition, task initiation, and sustained attention can include poor professional performance, relationship difficulties, and numerous health risks, collectively predisposing to a diminished quality of life and a reduction in life expectancy. As a consequence, the disorder costs society hundreds of billions of US dollars each year, worldwide. It is associated with other mental disorders as well as non-psychiatric disorders, which can cause additional impairment. While ADHD involves a lack of sustained attention to tasks, inhibitory deficits also can lead to diffic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties, and its behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code (its genotype) and the influence of environmental factors. Both factors may interact, further affecting the phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and again in his 1982 book '' The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-linked Recessive
''Main Article'': Sex linkage X-linked recessive inheritance is a mode of Mendelian inheritance, inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be always expressed in males (who are necessarily hemizygous for the gene mutation because they have one X and one Y chromosome) and in females who are homozygous for the gene mutation (see zygosity). Females with one copy of the mutated gene are carriers. X-linked inheritance means that the gene causing the trait or the disorder is located on the X chromosome. Females have two X chromosomes while males have one X and one Y chromosome. Carrier females who have only one copy of the mutation do not usually express the phenotype, although differences in X-chromosome inactivation (known as skewed X-inactivation) can lead to varying degrees of clinical expression in carrier females, since some cells will express one X allele and some will express the other. The current estimate of sequenced X-linked genes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemizygote
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
