Stuhrmann et al. (2001) studied a consanguineous Bedouin Saudi family who had four sons affected with familial thrombocytosis and aged 4 to 8 years. They had either sustained markedly elevated (greater than 1,000 x 10(9) per liter) or moderately elevated (greater than 500 x 10(9) per liter) platelet counts, but had normal plasma thrombopoietin levels and did not present with any thrombotic or hemorrhagic complications. In the two children with the highest platelet counts, minimal liver enlargement and mild to moderate splenomegaly was manifested. The first-cousin parents and the two daughters had normal platelet counts. None of the family members had the THPO intron 3 G>C mutation. In addition, segregation analysis using a polymorphic CA marker revealed completely discordant THPO alleles among the affected brothers, hence, excluding possible linkage between this gene and the disease in this family. Stuhrmann et al. (2001) stated that although parental consanguinity could argue for autosomal recessive inheritance, they considered X-linked recessive inheritance more likely.