Pedigrees, haplotypes, and TREM2 mutations in the Norwegian (A) and Swedish (B) families with PLOSL. Black symbols denote patients with PLOSL; half-black symbols denote heterozygous carriers of a mutated TREM2 allele; white symbols denote individuals who carry two wild-type alleles of TREM2. The 10-cM haplotypes were constructed by genotyping the following markers in both families: D6S1616-D6S1575-D6S1549 (from top to bottom in the figure). nt = position of mutated nucleotide. A, Haplotype 1-8-3 and 558G→A mutation, showing cosegregation with PLOSL in the Norwegian family. Haplotype 4-8-3 in the male carrier probably results from a recombination. B, Haplotype 4-7-3 and 233G→A substitution, cosegregating with PLOSL in the Swedish family.