Background Paternal uniparental disomy for chromosome 7 (upd(7)pat) is extremely rare, and only four cases have been previously reported. As these cases were accompanied by autosomal-recessive disorders which are likely to be involved in growth restriction, the relevance of upd(7)pat to the overgrowth phenotype remains unclear. Here we describe one case of upd(7)pat with no additional genetic diseases, which may answer the question.
Methods A 5-year-old Japanese boy presented with a tall stature of unknown causes. To detect the genetic cause of the tall stature, we performed Sanger sequencing, targeted resequencing, comparative genomic hybridisation and single-nucleotide polymorphism (SNP) array analyses, methylation analysis and microsatellite analysis.
Results We could not detect pathogenic variants in causative genes for overgrowth syndrome or apparent copy number alterations. DNA methylation analysis revealed hypomethylation at the GRB10, PEG1 and PEG10 differentially methylated regions. SNP array and microsatellite analyses suggested paternal uniparental isodisomy for chromosome 7. Furthermore, we could not identify homozygous mutations of known causative genes for inherited disorders on chromosome 7.
Conclusion We report the first case of upd(7)pat with an overgrowth phenotype.
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Contributors HO, KN and KK: performed analysis of sequence data. AN: molecular analysis other than genetic sequence analysis; wrote the paper. KM: clinical follow-up. MF and MK: edited the paper.
Funding The work was supported by grants from the Japan Agency for Medical Research and Development (16ek0109049h0003, 16ek0109030h0003 and 16ek0109141h0002), the National Center for Child Health and Development (28-6) and the Takeda Science Foundation, as well as Grants-in-Aid for Young Scientists (B) (16K21665) and for Challenging Exploratory Research (15K15096) from the Japan Society for the Promotion of Science.
Competing interests None declared.
Patient consent Guardian consent obtained.
Ethics approval Approval to conduct this study was obtained from the Ethical Committee of the Institutional Review Board Committee at the National Center for Child Health and Development (committee’s reference number: 518).
Provenance and peer review Not commissioned; externally peer reviewed.
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