Bart syndrome, also known as aplasia cutis congenita type VI, is a rare
genetic disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
characterized by the association of congenital localized absence of
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different de ...
, mucocutaneous blistering and absent and dystrophic nails.
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History
This clinical trial was first described by Bruce J Bart in 1966, who reported a large family with 26 affected members.
Clinical
1. Absence of skin at birth, involving the lower legs and feet, healing within a few months, leaving scarring and fragile skin.
2. Widespread blistering of the skin and mucous membranes.
3. Variable absence and dystrophy of nails.
Genetics
The syndrome is inherited by
autosomal dominant transmission with complete
penetrance
Penetrance in genetics is the proportion of individuals carrying a particular variant (or allele) of a gene (the genotype) that also express an associated trait (the phenotype). In medical genetics, the penetrance of a disease-causing mutation is t ...
but variable
expression
Expression may refer to:
Linguistics
* Expression (linguistics), a word, phrase, or sentence
* Fixed expression, a form of words with a specific meaning
* Idiom, a type of fixed expression
* Metaphorical expression, a particular word, phrase, o ...
. This means that children of an affected parent that carries the gene have a 50% chance of developing the disorder, although the extent to which they are affected is variable.
Blistering in Bart syndrome represents a form of epidermolysis bullosa caused by
ultrastructural
Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a co ...
abnormalities in the
anchoring fibrils. Genetic linkage of the inheritance of the disease points to the region of
chromosome 3
Chromosome 3 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 3 spans almost 200 million base pairs (the building material of DNA) and represents about 6.5 percent of the total DNA in ...
near the
collagen, type VII, alpha 1 gene (
COL7A1
Collagen alpha-1(VII) chain is a protein that in humans is encoded by the ''COL7A1'' gene. It is composed of a triple helical, collagenous domain flanked by two non-collagenous domains, and functions as an anchoring fibril between the dermal-epide ...
).
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See also
*
List of cutaneous conditions
*
Bart-Pumphrey syndrome
References
External links
{{Scleroprotein disease
Genodermatoses
Collagen disease
Syndromes affecting the skin
Diseases named for discoverer