A Case report: Co-occurrence of IMAGe syndrome and Rhabdomyosarcoma

Abstract

IMAGe syndrome is a rare congenital disorder, presenting with intrauterine growth restriction, metaphyseal dysplasia, adrenal hypoplasia congenita and genital anomalies (in males). So far only 17 individuals have been diagnosed molecularly with IMAGe syndrome, this patient is the first case of an individual diagnosed with IMAGe and concurrent rhabdomyosarcoma. The patient was born at 30 weeks' gestation and received treatment for hyponatremia and hyperkalemia. At 4 9/12 years of age the patient showed a painless, non-mobile mass on the left thigh. In the biopsy performed a sarcoma weave with solid, nest-like growth, with characteristics of rhabdomyosarcoma was identified. The family history and physical examination indicated IMAGe syndrome so genetic testing was requested. A whole exome sequencing procedure with use of SureSelectXT Human ALL Exon V7, confirmed a single nucleotide variant NM_000076.2(CDKN1C):c.820G>A (p.Asp274Asn); identifying a missense mutation in the imprinted gene CDKN1C associated with IMAGe syndrome. Although tumours associated with CDKN1C are rare, deregulation of imprinted genes is increasingly being recognised as a mechanism of tumorigenesis in cancer; chromosomal region 11p15.5 contains a cluster of imprinted genes. This same region is the most consistent site of allele loss in rhabdomyosarcoma and is the same region altered in both IMAGe and Beckwith-Wiedemann syndrome. Molecular studies have found genetic changes in the 11p15 region in a variety of embryonal tumours like Wilms tumours which are commonly developed in Beckwith-Wiedemann syndrome and embryonal rhabdomyosarcoma. Through this case we aim to present the possibility of oncogenesis in patients with IMAGe syndrome, specifically rhabdomyosarcoma.

Keywords: Beckwith-Wiedemann; CDKN1C; IMAGe syndrome; PCNA-binding; Paediatric tumour; Rhabdomyosarcoma.