Xeroderma pigmentosum is caused by mutations in genes that are involved in repairing damaged DNA. DNA can be damaged by UV rays from the sun and by toxic chemicals such as those found in cigarette smoke.
Is xeroderma pigmentosum recessive or dominant?
XP is an autosomal recessive inherited disorder. This means you must have 2 copies of an abnormal gene in order for the disease or trait to develop. The disorder is inherited from both your mother and father at the same time. The abnormal gene is rare, so the chances of both parents having the gene are very rare.
Why is xeroderma pigmentosum autosomal recessive?
XP is an autosomal recessive genetic condition caused by alterations (mutations) in nine different genes. Eight of the genes make up the nucleotide excision repair pathway (NER) that identities and repairs UV induced DNA damage. The ninth gene acts to bypass unrepaired damage.
Is there a genetic test for xeroderma pigmentosum?
Xeroderma pigmentosum (XP) is diagnosed based on the symptoms and clinical exam and may be confirmed by the results of genetic testing . Specialized testing may be done on skin cells to check for sensitivity to ultraviolet radiation .
What chromosome is xeroderma pigmentosum located on?
Xeroderma pigmentosum complementation group A (MIM ID #278700) is caused by mutations in the XPA gene (MIMID∗ 611153) and the most frequent mutation is a nonsense mutation (c. 682C>T, p. Arg228X) [26]. This gene is located on chromosome nine (9q34.
What type of mutation causes XP?
XP is a very rare autosomal recessive disorder that occurs in 1 in 250,000 births in the United States (Lehmann, Mcgibbon, & Stefanini, 2011; Menck & Munford, 2014). It is caused by rare, high-penetrant mutations in nucleotide excision repair (NER) genes.
What are the neurological symptoms of xeroderma pigmentosum?
Approximately 30% of XP patients present neurologic alterations, which may appear early in infancy or later in the second or third decade of life. They range from mild to severe, with intellectual disability, deafness, spasticity, and seizures [23].
Why is xeroderma pigmentosum more common in Japan?
XP patients have sun sensitivity, a 10,000-fold increased risk of skin cancer and defective DNA repair [4]. The frequency of XP in Japan is about 1:22,000 [5;6], which is much more common than in the US and Europe (about 1 per million) [2;6]. There are 8 XP DNA repair genes (XPA to XPG and XP variant).