Bazex-Dupre-Christol syndrome
Encyclopedia
Bazex-Dupre-Christol syndrome (also known as "Bazex syndrome," and "Follicular atrophoderma and basal cell carcinomas") is a very rare condition inherited in an X-linked dominant
fashion. Physical findings typically include follicular atrophoderma
, multiple basal cell carcinoma
s, hypotrichosis
and hypohidrosis.
This condition should not be confused with the unrelated condition Acrokeratosis paraneoplastica of Bazex
, which may also be referred to Bazex syndrome.
manner. This means the defective gene responsible for the disorder is located on the X chromosome, and only one copy of the defective gene is sufficient to cause the disorder when inherited from a parent who has the disorder. Males are normally hemizygous for the X chromosome, having only one copy. As a result, X-linked dominant disorders usually show higher expressivity
in males than females.
As the X chromosome is one of the sex chromosomes (the other being the Y chromosome
), X-linked
inheritance is determined by the gender
of the parent carrying a specific gene and can often seem complex. This is because, typically, female
s have two copies of the X-chromosome, while male
s have only one copy. The difference between dominant and recessive inheritance patterns also plays a role in determining the chances of a child inheriting an X-linked disorder from their parentage.
A locus of Xq24-q27 has been described. However, no gene has been identified.
X-linked dominant
X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome. As an inheritance pattern, it is less common than the X-linked recessive type...
fashion. Physical findings typically include follicular atrophoderma
Follicular atrophoderma
Follicular atrophoderma is a skin condition consisting of follicular indentations without hairs, notably occurring on extensor surfaces of the hands, legs, and arms.-References:...
, multiple basal cell carcinoma
Basal cell carcinoma
Basal-cell carcinoma is the most common type of skin cancer. It rarely metastasizes or kills. However, because it can cause significant destruction and disfigurement by invading surrounding tissues, it is still considered malignant. Statistically, approximately 3 out of 10 Caucasians may develop a...
s, hypotrichosis
Hypotrichosis
Hypotrichosis is a condition of abnormal hair patterns - predominantly loss or reduction. It occurs, most frequently, by the growth of vellus hair in areas of the body that normally produce terminal hair. Typically, the individual's hair growth is normal after birth, but shortly thereafter the hair...
and hypohidrosis.
This condition should not be confused with the unrelated condition Acrokeratosis paraneoplastica of Bazex
Acrokeratosis paraneoplastica of Bazex
Acrokeratosis paraneoplastica of Bazex is a cutaneous condition characterized by psoriasiform changes of hands, feet, ears, and nose, with involvement of the nails and periungual tissues being characteristic and indistinguishable from psoriatic nails...
, which may also be referred to Bazex syndrome.
Genetics
BCDS is inherited in an X-linked dominantX-linked dominant
X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome. As an inheritance pattern, it is less common than the X-linked recessive type...
manner. This means the defective gene responsible for the disorder is located on the X chromosome, and only one copy of the defective gene is sufficient to cause the disorder when inherited from a parent who has the disorder. Males are normally hemizygous for the X chromosome, having only one copy. As a result, X-linked dominant disorders usually show higher expressivity
Expressivity
Expressivity is a term used in genetics to refer to variations in a phenotype among individuals carrying a particular genotype. The term can be used to characterize qualitatively or quantitatively the extent of phenotypic variation given a particular genotype. The term is analogous to the...
in males than females.
As the X chromosome is one of the sex chromosomes (the other being the Y chromosome
Y chromosome
The Y chromosome is one of the two sex-determining chromosomes in most mammals, including humans. In mammals, it contains the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 60 million base pairs...
), X-linked
inheritance is determined by the gender
Gender
Gender is a range of characteristics used to distinguish between males and females, particularly in the cases of men and women and the masculine and feminine attributes assigned to them. Depending on the context, the discriminating characteristics vary from sex to social role to gender identity...
of the parent carrying a specific gene and can often seem complex. This is because, typically, female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
s have two copies of the X-chromosome, while male
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
s have only one copy. The difference between dominant and recessive inheritance patterns also plays a role in determining the chances of a child inheriting an X-linked disorder from their parentage.
A locus of Xq24-q27 has been described. However, no gene has been identified.