Question: How many people are affected by focal dermal hypoplasia ?
Answer: Focal dermal hypoplasia appears to be a rare condition, although its exact prevalence is unknown.
Source: GHR

Question: Is focal dermal hypoplasia inherited ?
Answer: Focal dermal hypoplasia is inherited in an X-linked dominant pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell is sufficient to cause the disorder. The X chromosome that contains the mutated PORCN gene may be turned on (active) or turned off (inactive) due to a process called X-inactivation. Early in embryonic development in females, one of the two X chromosomes is permanently inactivated in somatic cells (cells other than egg and sperm cells). X-inactivation ensures that females, like males, have only one active copy of the X chromosome in each body cell. Usually X-inactivation occurs randomly, so that each X chromosome is active in about half the body's cells. Sometimes X-inactivation is not random, and one X chromosome is active in more than half of cells. When X-inactivation does not occur randomly, it is called skewed X-inactivation. Researchers suspect that the distribution of active and inactive X chromosomes may play a role in determining the severity of focal dermal hypoplasia in females. In males (who have only one X chromosome), a mutation in the only copy of the PORCN gene in each cell appears to be lethal very early in development. A male can be born with focal dermal hypoplasia if he has a PORCN gene mutation in only some of his cells (known as mosaicism). Affected males typically experience milder symptoms of the disorder than females because more of their cells have a functional copy of the PORCN gene. A characteristic of focal dermal hypoplasia is that mildly affected fathers cannot pass this condition to their sons, but they can pass it to their daughters, who are usually more severely affected than they are. Women with focal dermal hypoplasia cannot pass this condition to their sons (because it is lethal early in development) but can pass it to their daughters. Most cases of focal dermal hypoplasia in females result from new mutations in the PORCN gene and occur in people with no history of the disorder in their family. When focal dermal hypoplasia occurs in males, it always results from a new mutation in this gene that is not inherited. Only about 5 percent of females with this condition inherit a mutation in the PORCN gene from a parent.
Source: GHR

Question: What are the treatments for focal dermal hypoplasia ?
Answer: These resources address the diagnosis or management of focal dermal hypoplasia: - Gene Review: Gene Review: Focal Dermal Hypoplasia - Genetic Testing Registry: Focal dermal hypoplasia - MedlinePlus Encyclopedia: Ectodermal dysplasia - MedlinePlus Encyclopedia: Omphalocele These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
Source: GHR