Chondrodysplasia punctata type 2 X - linked (X-linked chondrodysplasia punctata 2) - EBP Gen
Chondrodysplasia punctata type 2 The X - linked is a disease characterized by bone, skin and eye abnormalities that occur almost exclusively in women. Although the signs and symptoms of this disease are highly variable, most people affected by chondrodysplasia punctata type 2, have a dotted near the ends of the bones and cartilage, visible to X - ray In this form of chondrodysplasia punctata type 2, the dotted usually affects the long bones of the arms and the legs, ribs, vertebrae and cartilage that forms the trachea. Stippling is evident in childhood, but later disappears. Other skeletal abnormalities observed in individuals with chondrodysplasia punctata 2 X - linked, include shortening of the bones of the arms and thighs, often different on the right and left sides, and kyphoscoliosis. As a result of these anomalies, affected people tend to have short stature.
Chondrodysplasia punctata children with X - linked type 2 are born with dry scaly skin areas with a linear or spiral pattern. These scaly patches fade with time, leaving patches of abnormal skin color hairless. In addition, most affected individuals have the low and thick hair on your scalp, as well as cataracts from birth or early childhood. Other ocular abnormalities associated include microphthalmia and microcornea, which can affect vision.
In the women affected, intelligence and life expectancy are normal. However, in some men it can be a much more serious way. Affected males have some of the same characteristics that women affected and hypotonia, changes in brain structure, profound developmental delay, seizures, characteristic facial features and other birth defects. Health problems associated with chondrodysplasia punctata type 2 X - linked are often fatal in males.
This process is due to genetic alterations in the EBP gene, located on the short arm of chromosome X (Xp11.23-p11.22). This gene encodes the enzyme 3?-hydroxysteroid ?8, ?7 isomerase, which is responsible for one of the final steps for the production of cholesterol. Although excess cholesterol is a risk factor for heart disease, this molecule is required for normal embryonic development and has important roles both before and after birth, as it is a structural component of cell membranes and plays a role in the production of certain hormones and bile acids.
They have identified more than 55 mutations in the EBP gene in individuals with chondrodysplasia punctata type 2 linked to chromosome X. Some of the mutations responsible for the disease in women inserted or removed a small sequence of genetic material from EBP gene, while others change the amino acids in the enzyme 3?-hydroxysteroid ?8, ?7 isomerase. All these mutations alter the normal functioning of the enzyme, preventing the cells to produce enough cholesterol. Deficiency or absence of this enzyme also allowed to accumulate in the organism potentially toxic byproducts generated during the synthesis of cholesterol. The combination of low cholesterol levels and an accumulation of other substances, can disrupt the growth and development of many body systems. It is not known, however, how this alteration in the production of cholesterol leads to the specific characteristics of chondrodysplasia punctata 2 linked to X.
Rarely, in males has been observed chondrodysplasia punctata severe form of two X - linked These cases are due to changes involving single amino acids in the enzyme 3?-hydroxysteroid ?8, ?7 isomerase. Affected males have some of the same characteristics as the women affected, as well as changes in brain structure, moderate to profound developmental delays and other birth defects.
Chondrodysplasia punctata type 2 The X - linked inherited with a dominant X - linked pattern in women with two X chromosomes, a mutation in one of the two copies of the EBP gene in each cell is sufficient to express the alteration. Some cells produce normal amounts of 3?-hydroxysteroid ?8, ?7 isomerase and other cells produce no. In males, with a single X chromosome, a mutation in the EBP gene can lead to total loss of 3?-hydroxysteroid ?8, ?7 isomerase. An absence of this enzyme is usually fatal in the early stages of development, so few men are born with chondrodysplasia punctata 2 X - linked
Tests performed in IVAMI: in IVAMI perform detection of mutations associated with chondrodysplasia punctata type 2 linked to X through the complete PCR amplification of the exons of the EBP gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).