Somatic mosaic monosomy 7 and UPD7q in a child with MIRAGE syndrome caused by a novel SAMD9 mutation

Abstract

MIRAGE syndrome caused by mutations in SAMD9 is associated with potential loss of chromosome 7 (-7/7q-) and an increased risk to develop myelodysplastic syndrome (MDS). We report a case of MIRAGE syndrome, caused by a novel SAMD9 mutation p.Leu641Pro, leading to characteristic clinical features as well as to the coexistence of cells with monosomy 7 (20%) and with uniparental disomy of long arm of chromosome 7 (UPD7q). In contrast to previously reported MIRAGE patients with -7/7q- developing MDS, our patient achieved complete cytogenetic remission of monosomy 7. As UPD7q remained unchanged, it seems to be a protective factor against MDS.

Keywords: MIRAGE syndrome; SAMD9 mutation in mosaic form; UPD7q; monosomy 7; myelodysplastic syndrome.