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HNPCC is an autosomal inherited cancer syndrome characterized by germinal and somatic mutations of DNA mismatch repair (MMR) genes. The inherited mutation in one allele together with an acquired defect in the other allele of an MMR gene leads to accelerate tumor progression. In this study we analyzed a cohort of 11 subjects belonging to four Sicilian families with HNPCC suspected by molecular analysis of coding regions of hMSH2 (NC_000002) and hMLH1 (NC_000003) genes. Molecular analysis has detected the presence of two mutations in gene MSH2 and one mutation in MHL1 gene. In addition, we found a novel mutation consisting in a G deletion at 914 codon of the exon 16 in the MSH2 gene. This deletion leads to a stop codon due to a frame-shift, resulting in a truncated protein. We extended genetic analysis to the other family members and the same mutation was detected in three sisters and in one of the two healthy daughters. This mutation is correlated with clinical findings revealed in genealogic tree and it represents a novel mutation responsible of HNPCC., (Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.)

Introduction: Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol biosynthesis, resulting from deficient 7-dehydrocholesterol reductase (3beta-hydroxysterol Delta7-reductase) activity, the enzyme responsible for conversion of 7-dehydrocholesterol to cholesterol. SLOS is most common among people of European descent, with a reported incidence of 1 per 20,000-60,000 newborns, depending on the diagnostic criteria and the reference population. More than 80 different mutations have been identified in several hundred patients. In Italy, SLOS appears to be a rare condition, probably because of underdiagnosis., Method: We analyzed by direct sequencing the 7-dehydrocholesterol reductase gene (DHCR7) in a Sicilian patient with Smith-Lemli-Opitz syndrome and his parents in order to characterize the molecular defect., Results: The molecular analysis of the coding exons and the intron-exon boundaries of the DHCR7 gene demonstrated the presence of two missense mutations: a novel mutation (I251N) and a known mutation (E288K) responsible in a compound heterozygous state for a severe form of SLOS., Conclusion: The present study describes a Sicilian patient, a carrier of a novel mutation of the DHCR7 gene (I251N), which is responsible in a compound heterozygous state for a severe form of SLOS.