Roberts Syndrome

Epidemiology and Etiology:

· Human mitotic mutation syndrome that leads to secondary developmental defects

· Abnormality of sister chromatid apposition around the centromeres

· Particularly noticeable for chromosomes with large blocks of heterochromatin

Common sites:

·

Gross features:

· Craniofacial abnormalities

· Limb defects

· Often severe

Histologic features:

·

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

· Premature centromere separation (PCS) (~80%)

· Aka “heterochromatin repulsion” (HR)

· Best seen in plain-stained or C-banded chromosomes

· G-banding obscures it

Other features:

· Normal intellect

References:

· Gardner RJM, Sutherland GR. Chromosome abnormalities and genetic counseling. Oxford University Press; 2004.