Biomedical subjects

C S Dobkin

Publications and source records attributed to C S Dobkin.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Mode of inheritance influences behavioral expression and molecular control of cognitive deficits in female carriers of the fragile X syndrome.

The effect of mode of inheritance on expression of fragile X syndrome [fra(X)] was investigated in nonretarded female carriers. Examination included cognitive and molecular measures. A priori predictions about cognitive impairment and size of an unstable region of DNA containing a CGG repeat on the X chromosome were tested in age and education matched heterozygotes grouped according to parental inheritance. Nine carriers with a maternal fra(X) chromosome, 11 carriers with a paternal fra(X) chromosome and 15 control mothers of children with non X-linked developmental disabilities were tested. Inheritance was established through DNA linkage analysis. Cognitive skills were assessed using the Wechsler Adult Intelligence Scale-Revised and the Benton Visual Retention Test. Molecular status was assessed by Southern blot analysis of genomic DNA digested with Eco RI and Eag I, and probed with StB 12.3. Results supported the inheritance models' predictions. Heterozygotes who inherited the fra(X) from their fathers appeared to be a homogeneous group. They were indistinguishable from controls on cognitive measures and all had genomic insertions of less than 500 base pairs. In contrast, heterozygotes who inherited the fra(X) chromosome from their mothers appeared to be made up of 2 sub-populations. They were as a group deficient in measures of attention and visual memory, but not other measures, with scores of some women consistently below the other subjects. Further, they had some members with greater than 500 base pair inserts.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMedDate not supplied

New York State screening program for fragile X syndrome: a progress report.

New York State has established a program to screen post-pubertal mentally retarded males for the fragile X [fra(X)] syndrome. The goal of the program is to identify affected males and inform their families of the diagnosis. Females in these families who are at risk for inheriting the mutation will then be able to determine their carrier status and consider that information in making reproductive decisions. Males were evaluated for 10 features of the syndrome by physicians and nurses throughout the state; cytogenetic analysis was carried out on a subset of this population. A total of 1332 males has been screened and chromosome studies have been completed for 489. Forty-three (9%) were positive for fra(X), and an additional 11 other chromosome abnormalities were identified. The 43 patients belonged to 38 families. Of the 24 families who were informed of the diagnosis, 12 consulted genetic counseling centers for follow-up studies and 12 did not.

Adult↗

PubMedDate not supplied

Polymerase chain reaction analysis of fragile X mutations.

The mutation that underlies the fragile X syndrome is presumed to be a large expansion in the number of CGG repeats within the gene FMR-1. The unusually GC-rich composition of the expanded region has impeded attempts to amplify it by the polymerase chain reaction (PCR). We have developed a PCR protocol that successfully amplifies the (CGG)n region in normal, carrier and affected individuals. The PCR analysis of several large fragile X families is presented. The PCR results agree with those obtained by direct genomic Southern blot analyses. These favorable comparisons suggest that the PCR assay may be suitable for rapid testing for fragile X mutations and premutations and genetic screening of at-risk individuals.

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