Table 1 Methylation analysis of ICR1 and ICR2 in growth affected patients
No. patients studiedNo. patients affectedICR1 methylationICR2 methylationNotes of interestRefs
9 SRS5/9 SRSHypomethylation of H19 DMD/ICR1NormalUnaffected monozygotic twin; no hypomethylation in fibroblasts53
3 Con
3 SRS2/3 SRSExamined H19 promoter only.Complete hypomethylation of two SRS patientsNormalOne additional SRS patient had no methylation aberration69
2 Con7/7 IUGR
51 SRS16/51 SRSHypomethylation H19 DMD/ICR1: MI 20–37%Normal80% of patients with hypomethylation defects had body asymmetry70
58 SRS37/58 SRSH19 DMD/ICR1: MI 1–39%NormalOnly affects SRS patientsNormal IGFII serum in 82 patients64
69 SGA (Non-SRS)
1 SRS1 SRSNo methylation defects notedMaternal ICR2 duplicationmUPD 7 excluded; paternally expressed KCNQ1OT1 including maternally expressed KCNQ1, CDKNIC, SLC22A8, PHLDA271
  • BWS, Beckwith–Wiedemann syndrome; Con, controls; IUGR, intrauterine growth restriction; MI, methylation index; SGA, small for gestational age; SRS, Silver–Russell syndrome.