Figure 1. The pedigrees of the two families that took part in the study (denoted family 1 and 2 in the text) are displayed. Open and closed symbols denote unaffected and affected individuals, respectively. Deceased family members are denoted by diagonal lines; arrows indicate the probands in each family. A horizontal double line between parents indicates consanguinity. Panel A is a pedigree drawing of family 1, a first cousin consanguineous middle-eastern family, with four affected siblings. Panel B shows the nuclear family who took part in the study, and is part of a larger consanguineous pedigree not displayed or available for the study; the parents illustrated are first cousins.