Figure 1.

Homozygosity mapping and 2q haplotypes in four consanguineous families with BBGD. Blackened symbols indicate patients; unblackened symbols indicate unaffected individuals. Marker alleles, numbered as described in the “Material and Methods” section, are given for seven affected individuals and eight parents within four families with BBGD. Boxes highlight regions of complete homozygosity in affected individuals, indicating disease-chromosome haplotypes. Borders of the minimum candidate interval are denoted by the connected arrows. Genotypes that were not determined are shown by square brackets. Not shown, for confidentiality, are seven unaffected siblings in three of the families who were genotyped and included in the LOD score calculations. None of these samples showed homozygosity for the candidate region. On the basis of the results of mutation analysis, the first three families (11, 20, and 44), all of which involve first-cousin matings, likely share a common ancestor, with the difference in the allele for D2S1344 in family 44 likely being due to a change in the microsatellite marker repeat.