Figure 1. .

Four families from the Czech Republic used in the linkage and mutation analyses. Fully blackened symbols indicate individuals with MPS IIIC; arrowheads indicate probands. Measurements in seven obligate heterozygotes from these pedigrees (mean ± SD 11.6 ± 1.5 nmol/h/mg) and 89 controls not known to be related to members of the pedigree (mean ± SD 24.4 ± 5.7 nmol/h/mg) were used to establish N-acetyltransferase activity ranges for heterozygotes (symbols with blackened inner circle) and normal homozygotes (open symbols). An individual was assigned to a class if his or her enzyme activity was within 2 SDs of the class, unless the value was within the overlap of the upper end of the obligate heterozygotes and the lower end of the controls. Individuals with values within the open interval 13.0–14.6 nmol/h/mg were classified as unknown (symbols with gray inner circle). A symbol with a question mark (?) indicates that no material was available for the enzyme assay. DNA was available for individuals with ID numbers, and N-acetyltransferase activity measurements in white blood cells are shown below the ID numbers.