A case of paternal uniparental isodisomy for chromosome 7 associated with overgrowth.

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 , and 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.