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X-linked Reticulate Pigmentary Disorder
X-linked reticulate pigmentary disorder is a rare X-linked genetic condition in which males manifest multiple systemic symptoms and a reticulated mottled brown pigmentation of the skin, which, on biopsy, demonstrated dermal deposits of amyloid. Females usually only have linear streaks of hyperpigmentation. The syndrome is also referred to by the acronym X-Linked-PDR or XLPRD. It's a very rare disease, genetically determined, with a chronic course. It was characterized in 1981. Mutation of the ''POLA1'' gene leads to loss of expression of the catalytic subunit of DNA polymerase-α and is responsible for XLPDR. Loss of POLA1 expression results in reduced levels of RNA:DNA hybrids in the cytosol and unexpectedly triggers aberrant immune responses (e.g. type I interferon production) which at least in part can account for the symptoms associated with XLPDR. Another trigger of the immunodeficiency phenotype is a functional deficiency of NK cells, major players of innate antiviral immun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-linked Recessive
X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be always expressed in males (who are necessarily homozygous 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 is 499, and the total, including vaguely defined trait ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blaschko's Lines
Blaschko's lines, also called the lines of Blaschko, are lines of normal cell development in the skin. These lines are only visible in those with a mosaic skin condition or in chimeras where different cell lines contain different genes. These lines may express different amounts of melanin, or become visible due to a differing susceptibility to disease. In such individuals, they can become apparent as whorls, patches, streaks or lines in a linear or segmental distribution over the skin. They follow a ''V'' shape over the back, ''S''-shaped whirls over the chest and sides, and wavy shapes on the head. Not all mosaic skin conditions follow Blascko's lines. The lines are believed to trace the migration of embryonic cells. They do not correspond to nervous, muscular, or lymphatic systems. The lines are not unique to humans and can be observed in other non-human animals with mosaicism. Alfred Blaschko is credited with the first demonstration of these lines in 1901. Signs and sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waardenburg Syndrome
Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes (or Heterochromia iridum, one blue eye and one brown eye), a white forelock or patches of light skin. These basic features constitute type 2 of the condition; in type 1, there is also a wider gap between the inner corners of the eyes called telecanthus, telecanthus, or dystopia canthorum. In type 3, which is rare, the arms and hands are also malformed, with Camptodactyly, permanent finger contractures or fused fingers, while in type 4, the person also has Hirschsprung's disease. There also exist at least two types (2E and PCWH) that can result in central nervous system (CNS) symptoms such as developmental delay and muscle tone abnormalities. The syndrome is caused by mutations in any of several genes that affect the Cell division, division and Cell migration, migration of neural crest cells d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Cutaneous Conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square metres, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin.Burns, Tony; ''et al''. (2006) ''Rook's Textbook of Dermatology CD-ROM''. Wiley-Blackwell. . Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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