icf syndrome is a rare autosomal recessive disorder, characterised by variable immunodeficiency, mild facial anomalies and centromeric instability of chromosomes 1, 9, and 16. We started an international registry for an outline of the natural history of the disease. One of our families showed consanguinity more than 150 years ago. Linkage studies localised the gene on chromosome 20. Mutations in a dna methyltransferase gene dnmt3b were found in our patients. However, not all patients had mutations in this gene. At this moment we are looking for a second gene.
