Table 4.
Frequency of Deletions in Different Populations[Note]
|
Deletion Allele Frequencies (Chromosomes with Deletion/Total Chromosomes Sampled)a |
||||||
| Marker | Autism | Learning Disability | CEPH | Younger Control Subjectsb | Elderly Control Subjectsc | LOAD |
| D7S630 | .003 (1/388) | .0 (0/164) | .0 (0/238) | .0 (0/188) | .0 (0/574) | .0 (0/474) |
| D7S517 | .008 (3/388) | .0 (0/192) | .0 (0/253) | NA | NA | NA |
| del-D7S517A | .003 (1/388) | ND | ND | .0 (0/242) | .0 (0/504) | .0 (0/396) |
| del-D7S517B | .003 (1/388) | ND | ND | .0 (0/180) | .0 (0/498) | .0 (0/374) |
| del-D7S517C | .003 (1/388) | ND | ND | NA | NA | NA |
| D8S264 | .008 (3/388) | .0 (0/191) | .0 (0/270) | ND | ND | ND |
| D8S272 | .013 (5/388) | .005 (1/192)d | .104 (25/241) | .082 (14/170) | .035 (21/598) | .026 (13/494) |
Note.— ND = not determined. NA = not applicable. It is not possible to screen directly for del-D7S517C by a PCR assay. Therefore, the complete set of D7S517 deletions can be examined only by segregation of the D7S517 STRP in families with one or both parents sampled.
Autism, CEPH, and LD groups were initially screened for null alleles by examination of segregation patterns of marker genotypes in the families. All subjects in the families with autism were screened for deletions D7S630, del-D7S517A, del-D7S517B, and D8S272, by use of the direct assays described in figures 3, 5, and 7. These same deletion assays were used to screen the CEPH grandparents (in three-generation families) or parents (in two-generation families), and the control and LOAD populations, but not the families with LD. For the autism sample, the younger control subjects, elderly control subjects, and subjects with LOAD, the DNA samples were isolated directly from blood. For the subjects with LD, most of the DNA samples were isolated directly from blood with the rest from lymphoblastoid cell lines. All CEPH DNA samples were drawn from lymphoblastoid cell lines.
Younger control subjects were laboratory workers and subjects recruited by an advertisement for control subjects. The mean age was 36.9 years (SD = 12.7).
Elderly control subjects were spouses and caregivers of subjects with dementia who were seen by the University of Washington Alzheimer’s Disease Research Center. The mean age at the time of sampling was 73.5 years (SD = 8.56). Subjects with LOAD seen at the same clinic had a mean age at sampling of 73.3 years (SD = 9.34).
The families with LD were screened for the deletions only by use of segregation analysis of marker genotypes. The direct PCR assays for the deletions were not performed on these families.