ESPE Abstracts

Background: Silver Russell Syndrome (SRS) is characterized by pre- and postnatal growth failure, relative macrocephaly at birth, prominent forehead, feeding difficulties and body asymmetry. The diagnosis is clinical, the genetic mechanisms involved are different, in 50% of cases loss of methylation (LOM) at the paternal H19/IGF2:IG-DMR (chr11p15.5), in 10% of cases maternal uniparental disomy of chromosome 7 (UPD(7)mat), cases of maternal uniparental disomy of chromosome 20 (UPD(20) mat) are among the rarest causes of SRS/SRS-like phenotypes.

Case presentation: A 13-month-old girl was evaluated for poor growth and feeding difficulties. Born from unrelated parents at 39 weeks with weight 2096 g (-2.75 SDS), length 45 cm (-2.26 SDS), head circumference 30 cm (-3.16 SDS), at the first visit she showed length 64.8 cm (-4 SDS), weight 5680 g (-4.1 SDS), head circumference 42.5 cm (-1.99 SDS), prominent forehead, triangular face, mild hypertelorism, clinodactyly of the fifth finger, regular psychomotor development. Poor appetite and chronic constipation were reported. First level blood exams were negative. We suspected a Silver-Russell syndrome, analysis of the 11p15 region and UPD analysis of chromosome 7 were both negative. At 2 years of age, she presented height 73.5 cm (-3.74 SDS), weight 6,750 kg (-6.46 SDS), head circumference 44.5 cm (-1.93 SDS), BMI 12.5 (-3.46 SDS), NHCSS score 4, given the clinical suspicion of SRS, MLPA multi-locus Imprinting was required which highlighted on chromosome 20 hypomethylation in the NESP55 region and hypermethylation in the GNASXL and GNAS-AS1 regions, in the absence of CNV in the region. SNP-array analysis is ongoing. The patient is followed with a multidisciplinary approach, GHr therapy was proposed.

Conclusion: About 60% of patients with clinical suspicion of SRS receive a genetic diagnosis; in case of negativity of the molecular tests for the 11p15 region and for the UPD (7) mat, the Consensus Statement of SRS proposes to evaluate CNV and/or analysis of the 14q32 region, followed by research of UPD 16 mat, UPD(20)mat or search for mutations of CDKN1C or IGF2. Currently rare cases of SRS/SRS-like phenotype from UPD (20) mat are known, our case adds a further characterization of the phenotype. A better phenotypic characterization, deriving from the description of further cases, could make it possible to identify who to candidate with priority for the research of maternal UPD (20). Moreover the use of the multilocus MLPA technique will allow an easier identification of more cases.