De Sanctis-Cacchione syndrome

De Sanctis-Cacchione syndrome (DSC syndrome) is an extremely rare autosomal recessive disorder that represents the most severe clinical form of xeroderma pigmentosum (XP). First described in 1932 by De Sanctis and Cacchione, this condition is characterized by the combination of xeroderma pigmentosum with progressive neurological degeneration, dwarfism, and hypogonadism. The underlying cause involves defective nucleotide excision repair (NER) of UV-damaged DNA, and the syndrome has been associated with mutations in several XP complementation group genes, including ERCC6 (XPB), XPA, XPC, and XPD, among others. The syndrome affects multiple body systems. The skin is profoundly sensitive to ultraviolet radiation, leading to severe sunburn reactions, freckling, photodamage, and a markedly increased risk of skin cancers (basal cell carcinoma, squamous cell carcinoma, and melanoma) at a very young age. The nervous system is progressively affected, with features including intellectual disability, microcephaly, progressive sensorineural deafness, cerebellar ataxia, areflexia, choreoathetosis, and spasticity. Growth is impaired, resulting in short stature (dwarfism), and gonadal development is deficient (hypogonadism). Ocular manifestations include photophobia, keratitis, and corneal opacification. There is currently no cure for De Sanctis-Cacchione syndrome. Management is primarily supportive and preventive, focusing on rigorous protection from UV light exposure (protective clothing, sunscreen, UV-filtering window films) to reduce skin cancer risk, regular dermatological surveillance with early excision of skin malignancies, neurological supportive care, and management of endocrine deficiencies. Genetic counseling is recommended for affected families. Prognosis is generally poor, with significantly reduced life expectancy due to the combination of progressive neurodegeneration and early-onset skin cancers.

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