Adult-Onset Neuropsychiatric Symptoms as the Presenting Feature of Xeroderma Pigmentosum Group G: A Report of a Rare Case.

Xeroderma pigmentosum is a rare autosomal recessive disorder resulting in heightened cutaneous photosensitivity due to aberrant DNA repair mechanisms. Early-life developmental delay and cognitive impairment have been described in xeroderma pigmentosum cases. However, psychiatric symptoms in adulthood as the presenting feature of xeroderma pigmentosum have not been reported. We report a young adult with xeroderma pigmentosum group G presenting with prominent neuropsychiatric manifestations and evidence of neurodegeneration. The clinical, laboratory, and radiological findings, skin biopsy, and the results of the genetic testing of the patient have been described after obtaining written and informed consent. A young adult male with skin photosensitivity since infancy developed hyper-religiosity, delusions, suicidal ideations, speech hypernasality, lower limb spasticity, and cognitive impairment over the past four years. The MRI of the brain showed diffuse cerebral atrophy. The skin biopsy from bilateral cheeks showed evidence of flattening and thinning of rete ridges, pigment incontinence, and perivascular and periappendageal inflammatory infiltrate. The whole exome sequencing in ethylenediaminetetraacetic acid (EDTA) blood revealed a compound heterozygous likely pathogenic mutation in intron 13 (c.2880-2A>G (3' splice site)) and a mutation in exon 15 (c.3146del (p.Asp1049ValfsTer12)) in the ERCC5 gene suggestive of xeroderma pigmentosum group G. This case highlights that prominent neuropsychiatric features in adulthood can occur due to xeroderma pigmentosum. Thus, xeroderma pigmentosum group G should be considered as a possibility among young adults presenting with neuropsychiatric features, evidence of neurodegeneration, and early-life skin photosensitivity.