The cause of ichthyosis hystrix, Curth Macklin type is a defect in the development of the precursor, structural protein (tonofilaments). The defect occurs as a result of a change (mutation) in the gene that produces (codes for) these proteins. The faulty gene has been mapped to chromosome 12q13.
Ichthyosis Hystrix, Curth-Macklin type is an inherited disorder, transmitted as an autosomal dominant trait.
Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered. For example, “chromosome 12q13” refers to band 13 on the long arm of chromosome 12. The numbered bands specify the location of the thousands of genes that are present on each chromosome.
Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.
All individuals carry a few abnormal genes. Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child.