Smith–Lemli–Opitz syndrome among Arabs

Al-Owain M, Imtiaz F, Shuaib T, Edrees A, Al-Amoudi M, Sakati N, Al-Hassnan Z, Bamashmous H, Rahbeeni Z, Al-Ameer S, Faqeih E, Meyer B, Al-Hashem A, Garout W, Al-Odaib A, Rashed M, Al-Aama JY. Smith–Lemli–Opitz syndrome among Arabs. Smith–Lemli–Opitz syndrome (SLOS) is an autosomal recessive disorder of variable presentation caused by the deficiency of the 3β- hydroxycholesterol Δ7- reductase. Over the past 10 years, our biochemical laboratory has screened 191 plasma samples for possible SLOS, measuring the plasma cholesterol and 7-dehydrocholesterol using gas chromatography–mass spectrometry (GC-MS). The SLOS was confirmed in only five Arab patients with growth retardation, global developmental delay, dysmorphic features, and 2–3 toe syndactyly, among other findings. All cases represented moderate to severe form of SLOS. One patient had a unique cardiovascular malformation (cor triatriatum with significant obstruction of the right pulmonary veins). Two previously reported N287K (861 C>A) and R352Q (1055 G>A) and a novel R352L (1055 G>T) mutations were identified in the DHCR7 gene in these patients. The paper sheds light on this rare disease among Arabs and reviews all reported SLOS cases in the Arab population.