Phototesting in patients with Smith-Lemli-Opitz syndrome confirms sensitivity to UV-A [Letter]

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol metabolism first described in 1964.1 Patients with SLOS are deficient in 7-dehydrocholesterol reductase (DHCR7), the enzyme that catalyzes the final step of the cholesterol biosynthetic pathway, owing to disease-causing mutations in the DHCR7 gene located on chromosome 11q12.13. Deficiency in DHCR7 results in accumulation of cholesterol precursors, in particular, 7-dehydrocholesterol (7-DHC), and low levels of serum cholesterol. Clinical features are variable but include multiple malformations and developmental delay. Photosensitivity is now also a recognized feature, affecting about two thirds of patients with SLOS,2 - 3 with the action spectrum defined in 3 cases as falling in the UV-A range.3 Treatment for SLOS often includes a diet that is high in cholesterol, which parents of patients with SLOS report is of benefit for the photosensitivit