Attitudes toward the genetic testing of children among adults in a Utah-based kindred tested for a BRCA1 mutation.

Advances in molecular biology and genetics have led to the identification of the breast/ovarian cancer susceptibility genes BRCA1 and BRCA2, along with tests to detect mutations in these genes. Although the appropriateness of BRCA1/2 genetic testing for children has been debated in the literature, little is known about the attitudes of individuals who have undergone cancer susceptibility testing. The present study focused on attitudes toward BRCA1 testing for children among 218 adults from a Utah-based kindred who had received BRCA1 test results. Results indicated that approximately one-fourth of the participants would permit BRCA1 testing for children under the age of 18. General attitudes about genetic testing were predictive of attitudes toward the testing of children. In addition, men and individuals without a BRCA1 mutation were more likely to agree that minors should be allowed BRCA1 testing. Individuals whose mother had been affected with breast cancer were less likely to permit testing for minors. Among parents of minor children, less than one-fifth indicated that they would want BRCA1 testing for their own children; carrier status was not predictive of attitudes toward testing their own children. As breast/ovarian cancer susceptibility testing continues to be disseminated into clinical settings, there may be an increase in the number of test requests for minors. The findings of the present study represent an important step in exploring attitudes about genetic testing of children among individuals who have received cancer susceptibility test results.

Implications of a novel cryptic splice site in the BRCA1 gene.

This study was designed to determine the significance of a single intronic base change (IVS5-12 G-->A) found in a family with a history of breast cancer. This change is predicted to form a cryptic splice site resulting in the addition of 11 nucleotides to the BRCA1 transcript. The BRCA1 gene of the relatives and control individuals was sequenced and analyzed using RT-PCR, ASO hybridization, and size fractionation. All patients showed an 11 nucleotide insert at the intron 5/exon 6 boundary. This variant is likely to form a short protein product incapable of the hypothesized tumor suppressor functions of the BRCA1 gene. This information is important for providing counseling for families with this cryptic splice site and a family history of breast cancer.

Sequence analysis of BRCA1 and BRCA2: correlation of mutations with family history and ovarian cancer risk.

PURPOSE: Previous studies of mutations in BRCA1 or BRCA2 have used detection methods that may underestimate the actual frequency of mutations and have analyzed women using heterogeneous criteria for risk of hereditary cancer. PATIENTS AND METHODS: A total of 238 women with breast cancer before age 50 or ovarian cancer at any age and at least one first- or second-degree relative with either diagnosis underwent sequence analysis of BRCA1 followed by analysis of BRCA2 (except for 27 women who declined analysis of BRCA2 after a deleterious mutation was discovered in BRCA1). Results were correlated with personal and family history of malignancy. RESULTS: Deleterious mutations were identified in 94 (39%) women, including 59 of 117 (50%) from families with ovarian cancer and 35 of 121 (29%) from families without ovarian cancer. Mutations were identified in 14 of 70 (20%) women with just one other relative who developed breast cancer before age 50. In women with breast cancer, mutations in BRCA1 and BRCA2 were associated with a 10-fold increased risk of subsequent ovarian carcinoma (P = .005). CONCLUSION: Because mutations in BRCA1 and BRCA2 in women with breast cancer are associated with an increased risk of ovarian cancer, analysis of these genes should be considered for women diagnosed with breast cancer who have a high probability of carrying a mutation according to the statistical model developed with these data.

BRCA1 Testing: Genetic Counseling Protocol Development and Counseling Issues.

This article discusses the genetic counseling protocols which were developed and counseling issues that have arisen in the first 2 years of evaluating a large kindred with a BRCA1 mutation. The rationale for the development of the genetic counseling protocols and specific genetic counseling visual aids are presented and discussed. The protocols and counseling aids can serve as models for other programs offering cancer susceptibility testing. The observations of study counselors about study subject concerns and responses to genetic testing at the time of the pretest and posttest counseling sessions are presented.

Diagnosis of Duchenne and Becker muscular dystrophies by polymerase chain reaction. A multicenter study.

OBJECTIVE--To assess the efficiency, reliability, and ease of use of DNA diagnosis for Duchenne and Becker muscular dystrophies (DMD/BMD) using the polymerase chain reaction (PCR). DESIGN--DNA from the patients was screened for deletion mutations using multiplex PCR, and the results were compared with those obtained by Southern blot analysis. The PCR multiplex reaction detects nine specific "hot-spot" exons in the dystrophin gene while the Southern analysis detects 66 specific dystrophin gene restriction fragments. The multiplex reaction requires 50-fold less DNA than Southern analysis and thus is considerably more sensitive. SETTING--Fourteen university-affiliated and private genetic disease diagnostic laboratories. PATIENTS--Male patients with clinical signs of DMD/BMD. Cases were selected for analysis randomly, without knowledge of whether a deletion was present within the dystrophin gene. MAIN OUTCOME MEASURES--The percentage of cases that were detectable by multiplex PCR in comparison with Southern analysis, the frequency, extent, and location of the detected deletion mutations. In some cases, duplication mutations were monitored. RESULTS--The accuracy of a single PCR multiplex amplification (nine exons) was compared with Southern analysis with 10 cDNA probes that cover the full length of the gene. The multiplex PCR analytic method detected 82% of those deletions detected by Southern analysis methods. In one of 745 analyses, the multiplex method suggested a single exon deletion, which was not confirmed by Southern analysis, representing a false-positive rate of 0.013%. CONCLUSIONS--Multiplex PCR represents a sensitive and accurate method for deletion detection of 46% of all cases of DMD/BMD. The method requires 1 day for analysis, is easy to perform, and does not use radioactive tracers. As such, multiplex PCR represents an efficient and rapid method for prenatal or postnatal diagnosis of DMD/BMD.

Chromosome translocations in couples with multiple spontaneous abortions.

The reported incidence of balanced chromosomal translocations in couples with multiple spontaneous abortions (SABs) ranges from 0% of 31%. Because our experience has suggested that SABs are useful for ascertaining balanced translocations, we report the results of chromosome analyses performed on blood specimens from 440 individuals including 200 couples who were ascertained on the basis of two or more SABs. Balanced translocations were found in 3.6% of these 200 couples. For 122 of these couples, more detailed reproductive histories were available. For 48 couples with two SABs, four (8.4%) had balanced translocations; for 37 couples with three SABs, one (2.7%) had a balanced translocation; for 20 couples with four SABs, two (10%) had balanced translocations; and for 17 couples with five or more SABs, one (5.9%) had a balanced translocation. These 122 couples could also be classified on the basis of having abnormal or healthy children. For 40 couples with two or more SABs, one or more healthy children, and no abnormal offspring, two (5.0%) had balanced translocations; for 20 couples with two or more SABs and one or more abnormal children (and in some cases one or more healthy children), one (5.0%) had a balanced translocation; for 62 couples with two or more SABs and no other pregnancies, four (6.5%) had balanced translocations.