A pedigree of the studied family, showing typical autosomal-dominant inheritance of disease penetration. Members of the family, designated as FT-1 through FT-8, were clinically examined to certify affected or not. Solid symbols indicate affected members. Circles denote female family members, squares male family members, and symbols with a slash deceased family members. Plain numerals indicate peripheral platelet count, and italic numerals indicate serum concentration of TPO.