Ring chromosome 8 syndrome

Chromosome 8-derived supernumerary ring/marker is a rare chromosomal anomaly comprising variable parts of chromosome 8. The phenotype of mosaic or non-mosaic supernumerary r(8)/mar(8) ranges from almost normal to variable degrees of minor abnormalities, and growth and mental retardation overlapping with the well-known mosaic trisomy 8 syndrome (see this term).