SLOS diagnosis is important to consider in patients with developmental delays
Two case studies underscore the importance of considering Smith-Lemli-Opitz syndrome (SLOS) in the differential diagnosis of individuals presenting with developmental delays, language impairments, and distinctive facial features. Detecting elevated 7DHC levels and reduced cholesterol levels can aid in confirming the diagnosis. Initiating cholesterol supplementation, tailored to the patient’s needs, may alleviate symptoms, and promote developmental progress.
In the first case study, a three-year-old boy presented with developmental delay, including expressive language deficits and poor growth. Initial investigations failed to identify the underlying cause until biochemical genetic investigations revealed elevated levels of 7-dehydrocholesterol (7DHC), a characteristic marker of SLOS, and decreased cholesterol levels. Sanger sequencing confirmed compound heterozygosity for two pathogenic variants in the DHCR7 gene, which encodes the enzyme responsible for cholesterol synthesis. The patient exhibited improved development after initiating cholesterol powder supplementation, highlighting the potential benefits of targeted treatment strategies.
In the second case study, the older sister of the first patient was diagnosed with SLOS at six years of age. She presented with autism spectrum disorder, global developmental delay, and distinctive facial features. Biochemical analysis showed elevated 7DHC levels and reduced cholesterol levels, consistent with SLOS. Although confirmation of the specific pathogenic variants was unavailable, it was presumed that she shared the same mutations as her brother. Similar to her sibling, cholesterol supplementation was initiated, accompanied by targeted dietary interventions. The patient’s development showed signs of improvement, albeit with persistent challenges.
Reference
Coupe S, Hertzog A, Foran C, et al. Keeping you on your toes: Smith-Lemli-Opitz Syndrome is an easily missed cause of developmental delays. Clin Case Rep. 2023;11(2):e6920. doi: 10.1002/ccr3.6920. PMID: 36814711; PMCID: PMC9939576.
