Figure 1.

Families with the MPL-S505N mutation. (A) The pedigrees of the eight Italian families (pedigrees A-H) and one Japanese family (pedigree J) with the MPL-S505N mutation. Pedigree E is the index family that initiated this study. Squares represent males and circles females. Black symbols, represent affected individuals, open symbols, unaffected individuals, gray symbols, not studied. Unique patient numbers are shown below the symbols. Arrows mark the probands who initiated the family studies in each pedigree. (B) The genotypes of four informative microsatellite markers located closest to the MPL gene are shown below the corresponding family members in the pedigree. Numbers indicate the allele size in nucleotides. Affected alleles were determined by segregation analysis in family E and are marked in red (Italian families) and green (the Japanese family).