TY - JOUR T1 - <em>CDKN1C</em> hyperexpression in two patients with severe growth failure and microdeletions affecting the paternally inherited <em>KCNQ1OT1</em>:TSS-DMR JF - Journal of Medical Genetics JO - J Med Genet DO - 10.1136/jmg-2022-108700 SP - jmedgenet-2022-108700 AU - Kaori Hara-Isono AU - Kazuki Yamazawa AU - Satsuki Tanaka AU - Eriko Nishi AU - Maki Fukami AU - Masayo Kagami Y1 - 2022/07/29 UR - http://jmg.bmj.com/content/early/2022/07/29/jmg-2022-108700.abstract N2 - Background Two imprinting control centres, H19/IGF2:IG-differentialy methylated region (DMR) and KCNQ1OT1:TSS-DMR, reside on chromosome 11p15.5. Paternal deletions involving the KCNQ1OT1:TSS-DMR result in variable phenotypes, namely, normal phenotype, Silver-Russel syndrome (SRS) and fetal demise. However, expression analyses for CDKN1C in these patients are very limited.Cases Patient 1 (adult woman) and patient 2 (boy in early childhood) showed prenatal and postnatal growth failure and clinical suspicion of SRS.Molecular analyses Both patients showed hypermethylation of the KCNQ1OT1:TSS-DMR caused by the paternal heterozygous de novo deletions involving the KCNQ1OT1:TSS-DMR, but not including CDKN1C enhancers. The deletion sizes were 5 kb and 12 kb for patients 1 and 2, respectively. CDKN1C gene expressions in immortalised leucocytes of both patients were increased compared with those of controls.Conclusion Paternal deletions involving the KCNQ1OT1:TSS-DMR, but not including CDKN1C enhancers, disrupt KCNQ1OT1 expression, strongly activate CDKN1C expression and consequently cause severe growth failure. ER -