We aimed to determine if an adolescent patient presenting with neurological impairment has xeroderma pigmentosum (XP). For this purpose, whole-exome sequencing was performed to assess mutations in XP genes. Dermal fibroblasts were established from a skin biopsy and XPA expression determined by immunoblotting. Nucleotide excision repair (NER) capacity was measured by detection of unscheduled DNA synthesis (UDS) in UVC-irradiated patient fibroblasts. Genetic analysis revealed two recessive mutations in XPA, one known c.682C>T, p.Arg228Ter, and the other c.553C>T, p.Gln185Ter, only two cases were reported. XPA protein was virtually undetectable in lysates from patient-derived fibroblast. The patient had significantly lower UV-induced UDS (3.03 ± 1.95%, p < 0.0001) compared with healthy controls (C5RO = 100 ± 12.2; C1UMN = 118 ± 5.87), indicating significant NER impairment. In conclusion, measurement of NER capacity is beneficial for the diagnosis of XP and in understanding the functional impact of novel mutations in XP genes. Our findings highlight the importance of neurologists considering XP in their differential diagnosis when evaluating patients with atypical neurodegeneration.
Bibliographical noteFunding Information:
This study was supported by the Servicio Murciano de Salud (Spain), NIH grant U01ES029603 and the Irene Diamond Fund/American Federation on Aging Research Postdoctoral Transition Award (US).
The authors wish to thank Pablo Conesa-Zamora, from the Department of Pathological Anatomy at Santa Lucia University Hospital of Cartagena, Spain, who prepared the culture media for the shipment from Spain to the USA. The authors also thank the patient and her family for participating in the study. Funding. This study was supported by the Servicio Murciano de Salud (Spain), NIH grant U01ES029603 and the Irene Diamond Fund/American Federation on Aging Research Postdoctoral Transition Award (US).
© Copyright © 2021 García-Carmona, Yousefzadeh, Alarcón-Soldevilla, Fages-Caravaca, Kieu, Witt, López-Ávila, Niedernhofer and Pérez-Vicente.
- DNA repair activity
- neurode generation
- nucleotide excision repair
- rare diseases
- xeroderma pigmentosum group A