XP affects people of all races and has been reported on all continents. However, certain regions have a higher incidence than others. The incidence of XP is estimated to be 1 per million live births in the US, 2.3 per million live births in western Europe, 17.5 per million live births in the Middle East, and 45 per million live births in Japan.[5]Kleijer WJ, Laugel V, Berneburg M, et al. Incidence of DNA repair deficiency disorders in western Europe: xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy. DNA Repair (Amst). 2008 May 3;7(5):744-50.
https://www.doi.org/10.1016/j.dnarep.2008.01.014
http://www.ncbi.nlm.nih.gov/pubmed/18329345?tool=bestpractice.com
[6]Bhutto AM, Kirk SH. Population distribution of xeroderma pigmentosum. In: Ahmad SI, Hanaoka F, eds. Molecular mechanisms of xeroderma pigmentosum. Advances in experimental medicine and biology. Vol 637. New York, NY: Springer; 2008.[7]Leung AK, Barankin B, Lam JM, et al. Xeroderma pigmentosum: an updated review. Drugs Context. 2022;11:2022-2-5.
https://www.doi.org/10.7573/dic.2022-2-5
http://www.ncbi.nlm.nih.gov/pubmed/35520754?tool=bestpractice.com
Studies have shown that the incidence of XP is increased in countries where consanguinity is common, such as Tunisia, Morocco, Libya and Pakistan.[6]Bhutto AM, Kirk SH. Population distribution of xeroderma pigmentosum. In: Ahmad SI, Hanaoka F, eds. Molecular mechanisms of xeroderma pigmentosum. Advances in experimental medicine and biology. Vol 637. New York, NY: Springer; 2008.[8]Zghal M, El-Fekih N, Fazaa B, et al. [Xeroderma pigmentosum. Cutaneous, ocular, and neurologic abnormalities in 49 Tunisian cases]. [in fre]. Tunis Med. 2005 Dec;83(12):760-3.
http://www.ncbi.nlm.nih.gov/pubmed/16450945?tool=bestpractice.com
[9]Moussaid L, Benchikhi H, Boukind EH, et al. [Cutaneous tumors during xeroderma pigmentosum in Morocco: study of 120 patients]. [in fre]. Ann Dermatol Venereol. 2004 Jan;131(1 pt 1):29-33.
http://www.ncbi.nlm.nih.gov/pubmed/15041840?tool=bestpractice.com
[10]Khatri ML, Bemghazil M, Shafi M, et al. Xeroderma pigmentosum in Libya. Int J Dermatol. 1999 Jul;38(7):520-4.
http://www.ncbi.nlm.nih.gov/pubmed/10440281?tool=bestpractice.com
[11]Bhutto AM, Shaikh A, Nonaka S. Incidence of xeroderma pigmentosum in Larkana, Pakistan: a 7-year study. Br J Dermatol. 2005 Mar;152(3):545-51.
http://www.ncbi.nlm.nih.gov/pubmed/15787826?tool=bestpractice.com
Subtype XPC is the most common subtype in the US, Europe, and Africa.[12]Giordano CN, Yew YW, Spivak G, et al. Understanding photodermatoses associated with defective DNA repair: syndromes with cancer predisposition. J Am Acad Dermatol. 2016 Nov;75(5):855-70.
http://www.ncbi.nlm.nih.gov/pubmed/27745641?tool=bestpractice.com
Subtype XPA is the most common subtype in China and Japan, with more than 50% of patients with XP in Japan having the XPA subtype.[2]Moriwaki S, Kanda F, Hayashi M, et al. Xeroderma pigmentosum clinical practice guidelines. J Dermatol. 2017 Oct;44(10):1087-96.
https://www.doi.org/10.1111/1346-8138.13907
http://www.ncbi.nlm.nih.gov/pubmed/28771907?tool=bestpractice.com
[12]Giordano CN, Yew YW, Spivak G, et al. Understanding photodermatoses associated with defective DNA repair: syndromes with cancer predisposition. J Am Acad Dermatol. 2016 Nov;75(5):855-70.
http://www.ncbi.nlm.nih.gov/pubmed/27745641?tool=bestpractice.com
[13]Nishigori C, Nakano E, Masaki T, et al. Characteristics of xeroderma pigmentosum in Japan: lessons from two clinical surveys and measures for patient care. Photochem Photobiol. 2019 Jan;95(1):140-53.
https://www.doi.org/10.1111/php.13052
http://www.ncbi.nlm.nih.gov/pubmed/30565713?tool=bestpractice.com
Since XP is an autosomal recessive inherited disorder, males and females are equally affected.
Patients usually present at a young age (<2 years old). The average age at onset of first skin cancer in these patients is <10 years old.[14]DiGiovanna JJ, Kraemer KH. Shining a light on xeroderma pigmentosum. J Invest Dermatol. 2012 Mar;132(3 pt 2):785-96.
https://www.doi.org/10.1038/jid.2011.426
http://www.ncbi.nlm.nih.gov/pubmed/22217736?tool=bestpractice.com
When adults present with XP, they tend to be aged between 20 and 40 years with numerous premalignant or malignant skin cancers.[2]Moriwaki S, Kanda F, Hayashi M, et al. Xeroderma pigmentosum clinical practice guidelines. J Dermatol. 2017 Oct;44(10):1087-96.
https://www.doi.org/10.1111/1346-8138.13907
http://www.ncbi.nlm.nih.gov/pubmed/28771907?tool=bestpractice.com