Two siblings with immunodeficiency, facial abnormalities and chromosomal instability without mutation in DNMT3B gene but liability towards malignancy; a new chromatin disorder delineation?

ICF syndrome (standing for Immunodeficiency, Centromere instability and Facial anomalies syndrome) is a very rare autosomal recessive immune disorder caused by mutations of the gene de novo DNA-methyltransferase 3B (DNMT3B). However, in the literature similar clinical cases without such mutations are reported, as well.We report on a family in which the unrelated spouses had two female siblings sharing similar phenotypic features resembling ICF-syndrome, i.e. congenital abnormalities, immunodeficiency, developmental delay and high level of chromosomal instability, including high frequency of centromeric/pericentromeric rearrangements and breaks, chromosomal fragments despiralization or pulverization. However, mutations in DNMT3B could not be detected.The discovery of a new so-called 'chromatin disorder' is suggested. Clinical, molecular genetic and cytogenetic characteristics are reported and compared to other 'chromatin disorders'.