Chromatograms of PRX alterations identified in three families. Families HOU297, HOU579, and HOU418 exhibit autosomal recessive inheritance. Blackened symbols indicate DSN. Patient 851, from family HOU297, is compound heterozygous for mutations S929fsX957 and R953X; her older unaffected son is heterozygous for R953X (data not shown). Patient 1461, from family HOU579, is compound heterozygous for mutations V763fsX774 and R368X; her unaffected brother is heterozygous for V763fsX774 (data not shown). Patient 1136 from family HOU418 has the homozygous mutation S929fsX957; her two unaffected sisters and her son are heterozygous for this mutation (data not shown).