Factor X deficiency and Factor XI deficiency (Rosenthal syndrome) are two types of inherited autosomal recessive bleeding disorders characterised by haemorrhagic conditions of variable severity. Defects in the F10 gene on chromosome 13q34 is the main cause of Factor X deficiency. The vitamin K-dependent protein encoded by this gene is coagulation factor X. Defects in the F11 gene on chromosome 4q35 is the main cause of Factor XI deficiency. The protein encoded by this gene is coagulation factor XI. The F10 gene (8 exons) spans ~27 kb of genomic DNA and is located on 13q34, 114 Mb from the p-telomere. The F11 gene (15 exons) spans ~24 kb of genomic DNA and is located on 4q35.2, 187 Mb from the p-telomere. The P440-A1 probemix contains one probe for each exon of the two mentioned genes and two probes for the both exons 1. In addition, 13 reference probes are included in this probemix, detecting several different autosomal chromosomal locations. Possible copy number changes of this genomic region in healthy individuals can be found in the database of genome variants .