Epigenetic and genetic diagnosis of Silver-Russell syndrome.

Silver-Russell syndrome (SRS) is a congenital imprinting disorder characterized by intrauterine and postnatal growth restriction and further characteristic features. SRS is genetically heterogenous: 7-10% of patients carry a maternal uniparental disomy of chromosome 7; >38% show a hypomethylation in imprinting control region 1 in 11p15; and a further class of mutations are copy number variations affecting different chromosomes, but mainly 11p15 and 7. The diagnostic work-up should thus aim to detect these three molecular subtypes. Numerous techniques are currently applied in genetic SRS testing, but none of them covers all known (epi)mutations, and they should therefore be used synergistically. However, future next-generation sequencing approaches will allow a comprehensive analysis of all types of alterations in SRS.