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Biomedical subjects

D Goldgar

Publications and source records attributed to D Goldgar.

At least 37 records · Page 2Linked to original sources

Risk and penetrance of primary hyperparathyroidism in multiple endocrine neoplasia type 2A families with mutations at codon 634 of the RET proto-oncogene. Groupe D'etude des Tumeurs à Calcitonine.

Germline mutations of the RET proto-oncogene are responsible for multiple endocrine neoplasia type 2, including multiple endocrine type 2A (MEN 2A), type 2B (MEN 2B), and familial medullary thyroid carcinoma. The relationship between specific mutations and syndromic features has been established. In particular, the risk for pheochromocytoma and hyperparathyroidism (HPT) in MEN 2A patients is clearly associated with the presence of the RET mutation at a specific position, i.e. at codon 634. Also, a correlation between a specific mutation, C634R, and the development of HPT has been suggested but is still controversial. To further investigate the relationship between specific mutations of codon 634 and the development of HPT, we studied a population of 188 individuals, carrying mutations at codon 634, namely C634R (65 patients belonging to 10 families), C634Y (80 patients belonging to 11 families), or the less frequent codon 634 mutations [i.e. C634S, C634F, C634G, or C634W (43 patients belonging to 9 families)]. In this series of patients, we defined an overall HPT prevalence of 19.1% and found that this prevalence did not vary significantly, with respect to the nature of the mutation. However, irrespective of the particular mutation, the prevalence of HPT showed a high interfamilial variability. The statistical model that best fitted with the observed data was in favor of the heterogeneity of the risk for HPT, with 40% of the families showing an HPT risk of 34% and 60% of the families showing an HPT risk of 9%. In addition, our study clearly demonstrated that HPT could be an early component of the disease and provided the first estimate of age-specific and mutation-specific HPT penetrance in individuals with mutations of codon 634 of the RET proto-oncogene.

Adult↗

Mutations in BRCA1 and BRCA2 in breast cancer families: are there more breast cancer-susceptibility genes?

To estimate the proportion of breast cancer families due to BRCA1 or BRCA2, we performed mutation screening of the entire coding regions of both genes supplemented with linkage analysis of 31 families, 8 containing male breast cancers and 23 site-specific female breast cancer. A combination of protein-truncation test and SSCP or heteroduplex analyses was used for mutation screening complemented, where possible, by the analysis of expression level of BRCA1 and BRCA2 alleles. Six of the eight families with male breast cancer revealed frameshift mutations, two in BRCA1 and four in BRCA2. Although most families with female site-specific breast cancers were thought to be due to mutations in either BRCA1 or BRCA2, we identified only eight mutations in our series of 23 site-specific female breast cancer families (34%), four in BRCA1 and four in BRCA2. According to the posterior probabilities calculated for mutation-negative families, based on linkage data and mutation screening results, we would expect 8-10 site-specific female breast cancer families of our series to be due to neither BRCA1 nor BRCA2. Thus, our results suggest the existence of at least one more major breast cancer-susceptibility gene.

BRCA1 Protein↗

Germline BRCA1 185delAG mutations in Jewish women with breast cancer.

BACKGROUND: We aimed to find out the proportion of breast cancers in Ashkenazi Jewish women attributable to the frameshift mutation at position 185 involving the deletion of adenine and guanine (185delAG) in the breast cancer gene BRCA1. METHODS: We studied 107 Ashkenazi Jewish women with breast cancer seen at medical oncology and genetic counseling clinics in New York over a three and a half year period beginning in 1992. 80 of the women were diagnosed before age 42 years; the other 27 were diagnosed between 42 and 50 years and had a positive family history. Genomic DNA testing by PCR amplification was done to identify any 185delAG mutations of the BRCA1 gene. FINDINGS: Of the 80 women diagnosed before the age of 42 years, 16 (20%, 95% CI 11.2-28.8) were heterozygous for the mutation. All 16 women had at least one first-degree or second-degree relative with breast or ovarian cancer. Of 27 probands diagnosed with breast cancer between the ages of 42 and 50 years who had at least one first-degree relative affected with breast or ovarian cancer, 8 (30%, 95% CI 12-47) had 185delAG mutations. INTERPRETATION: These data suggest that screening for the 185delAG mutation may be useful in genetic counselling of these women where options for detection and prevention of possible cancers can be discussed.

Adult↗

Recurrent BRCA2 6174delT mutations in Ashkenazi Jewish women affected by breast cancer.

The lifetime risk of breast cancer may approach 80-90% in women who have germline mutations of either of two genes, BRCA1 or BRCA2. A single BRCA1 mutation, 185delAG, has been noted in approximately 20% of Ashkenazi Jewish women with early onset breast cancer and in 0.9% of the Ashkenazi population. We recently detected a 6174delT frameshift mutation in BRCA2 in an hereditary breast cancer kindred of Ashkenazi Jewish ancestry. Here, we investigated the frequency of this mutation in 200 women with early-onset breast cancer. Six of 80 Ashkenazi Jewish women (8%) diagnosed with breast cancer before the age of 42, wer heterozygous for the 6174delT mutation, compared to none of 93 non-Jewish women diagnosed with breast cancer at the same age (P = .005). These cases were ascertained without regard to family history. Two of 27 (7%) additional Jewish families in which the proband was diagnosed with breast cancer at age 42 to 50 and had a family history of breast or ovarian cancer had germline 6174delT mutations. The results of this report suggest that a recurrent mutation of BRCA1 and a recurrent mutation BRCA2 together may account for over a quarter of all early-onset breast cancer in the setting of a personal or family history of ovarian cancer in Ashkenazi Jewish women.

Adult↗

The carrier frequency of the BRCA2 6174delT mutation among Ashkenazi Jewish individuals is approximately 1%.

Certain germline mutations in either BRCA1 or BRCA2 confer a lifetime risk of developing breast cancer that may approach 90%. The BRCA1 185delAG mutation was found in 20% and the BRCA2 6174delT mutation in 8% of Ashkenazi Jewish women with early-onset breast cancer. The 185delAG mutation was observed in 0.9% of 858 Ashkenazi Jews unselected for a personal or family history of cancer. Assuming comparable age-specific penetrances, a carrier frequency of 0.3% was estimated for the 6174delT BRCA2 mutation. To test this hypothesis, we performed a population survey of 1,255 Jewish individuals. In two independent groups, a prevalence of approximately 1% (C.I. 0.6-1.5) was observed for the 6174delT mutation. The relative risk of developing breast cancer by age 42 was estimated to be 9.3 (C.I. 2.5-22.5) for 6174delT, compared to 31 (C.I. 11-77) for 185delAG. Analysis of 107 Ashkenazi Jewish women with breast cancer and a family history of breast or ovarian cancer confirmed a four-fold greater prevalence for the BRCA1 185delAG mutation compared to the BRCA2 6174delT mutation. Our findings suggest a difference in cumulative life-time penetrance for the two mutations. Genetic counseling for the one in 50 Ashkenazi Jewish individuals harbouring specific germline mutations in BRCA1 or BRCA2 must be tailored to reflect the different risks associated with the two mutations.

Adult↗

Risk modifiers in carriers of BRCA1 mutations.

The majority of, but not all, women with mutations in the BRCA1 gene will be affected with breast or ovarian cancer by the age of 70. To establish whether known risk factors modify susceptibility to cancer in these women, we have studied the reproductive histories of 333 North American women who were found by haplotype analysis to carry BRCA1 mutations. An increased risk for breast cancer was associated with low parity and with recent birth cohort. The risk of ovarian cancer decreased with increasing age at last childbirth; however, in contrast to the case for sporadic cancer, the risk of ovarian cancer in BRCA1 carriers was found to increase significantly with increasing parity.

Adult↗

Further localization of the gene for nevoid basal cell carcinoma syndrome (NBCCS) in 15 Australasian families: linkage and loss of heterozygosity.

Nevoid basal cell carcinoma syndrome (NBCCS; basal cell nevus syndrome or Gorlin syndrome) is a cancer-predisposition syndrome characterized by multiple basal cell carcinomas (BCCs) and diverse developmental defects. The gene for NBCCS has been mapped to 9q23.1-q31 in North American and European families. In addition, loss of heterozygosity (LOH) for genetic markers in this region has been detected in sporadic BCCs, indicating that the NBCCS gene is probably a tumor-suppressor gene. In this study we have determined that the NBCCS gene is also linked to this region in Australasian pedigrees and that there is no significant evidence of heterogeneity. We have defined the localization of the gene by multipoint and haplotype analysis of 15 families, using four microsatellite markers. LOH at these loci was detected in 50% of sporadic BCCs, a rate that is significantly higher than that in other skin lesions used as controls.

Adult↗

Effect of progestin therapy on cortical and trabecular bone: comparison with estrogen.

PURPOSE: To determine the effect of progestin therapy on bone mineral density in postmenopausal women and to compare its effects to those of estrogen. SUBJECTS AND METHODS: A prospective, randomized clinical trial was performed in 81 postmenopausal women aged 51.7 +/- 4.4 years (mean +/- SD). They were assigned to one of four groups: Provera 20 mg, Premarin 0.6 mg, Premarin 0.3 mg plus Provera 10 mg, and a placebo. In addition, all women received calcium supplementation, if necessary, to a calcium intake of 1,000 mg/day. We used single- and dual-photon absorpiometry, metacarpal radiogrammetry, and computed axial tomography to measure bone mineral density in the total skeleton, spine, radius, and metacarpal. RESULTS: Women receiving placebo lost bone at all sites (p less than 0.01). The Provera-treated group showed no change in total body calcium, but there were decreases in radial density (p less than 0.01), metacarpal cortex (p less than 0.01), and spine density (p less than 0.01). The Premarin-treated group had an increase in spine density and total body density (p less than 0.05), but a decrease in radial density (p less than 0.05). The Premarin-plus-Provera group showed no change in spine density, total body calcium, or radial density but had a decrease in metacarpal cortex (p less than 0.01). CONCLUSIONS: Compared to placebo, Provera reduced the rate of loss in cortical areas of the skeleton, but not in the spine, which contains more trabecular bone. In contrast, Premarin reduced the rate of loss in both cortical and trabecular areas of the skeleton. The low-dose combination of Premarin plus Provera was similar in its effect on bone to that of Premarin alone, suggesting that there may be a synergistic effect of this hormone combination on bone. Serum cholesterol levels decreased with Provera, Premarin, and the combination of both, whereas levels of serum triglycerides increased with Premarin treatment, decreased with the Provera regimen, and were unchanged with the combination therapy. Provera does not adversely affect the lipid profile.

Bone Density↗

Treatment of postmenopausal osteoporosis with high doses of synthetic calcitriol. A randomized controlled study.

OBJECTIVE: To study the efficacy of synthetic 1,25 dihydroxyvitamin D3 (calcitriol) in the treatment of osteoporosis. DESIGN: Two-year, double-blind, randomized clinical trial. SETTING: University medical center. PATIENTS: Fifty postmenopausal women with vertebral fractures recruited by referral. INTERVENTION: Calcium intake was adjusted to 25 mmol/d (1000 mg/d) at baseline. Patients were then randomized to treatment with either calcitriol or placebo. During the study, calcium intake was reduced to 15 mmol/d (600 mg/d) and the dose of calcitriol was adjusted to maintain serum calcium less than 2.74 mmol/L (less than 11.0 mg/dL) or urine calcium less than 9.96 mmol/d (less than 400 mg/d). MEASUREMENTS AND MAIN RESULTS: After 2 years, the mean dose of calcitriol in the treated group was 0.62 micrograms/d. Bone mineral density of the spine increased 1.94% with calcitriol therapy and decreased 3.92% with placebo (P = 0.001). Total body calcium increased 0.21% with calcitriol therapy and decreased 1.85% with placebo (P = 0.004). Patients receiving placebo had significant decreases in spine density (P = 0.0007) and total body calcium (P = 0.0004). There were no differences in vertebral fracture rates between the groups. Renal function studies were not statistically different between the groups after 2 years. CONCLUSION: The treatment of postmenopausal osteoporotic women with synthetic calcitriol for 2 years was associated with increases in spine density and total body calcium. No adverse effects on renal function were seen after long-term calcitriol therapy.

Aged↗

Lipid changes after hormone replacement therapy for menopause.

Three regimens of hormone replacement therapy were administered to 62 postmenopausal women for a period of 12 weeks and evaluated for their effect on blood lipids. Each group was given a continuous dose of 0.625 mg of conjugated estrogens combined with either a continuous dose of 2.5 mg of medroxyprogesterone acetate or 5.0 mg of medroxyprogesterone acetate, or a cyclic dose of 5.0 mg of medroxyprogesterone acetate on days 17-28 of the cycle. After treatment there was a significant decrease in the total cholesterol (P less than .0007) and low density lipoprotein cholesterol (P less than .0001) together with a significant increase in high density lipoprotein cholesterol (P less than .0029). There was no significant difference in the response of the blood lipids to the three hormone groups. Therefore, preference would depend on the combination that caused the least bleeding or amenorrhea.

Alanine Transaminase↗

The dysplastic melanocytic nevus: a prevalent lesion that correlates poorly with clinical phenotype.

We estimated the prevalence of persons with histologic dysplasia in at least one of two nevi examined by biopsy to be 53% in Utah's caucasians. This apparently high prevalence indicates that such lesions may represent a normal variant of a melanocytic nevus, perhaps those in the process of active proliferation. Regardless of the apparent ubiquity of these lesions, examination of biopsy specimens led to a grading scheme of histologic dysplasia that may reflect chronologic stages in the neoplastic development of melanocytic nevi. Comparison of these histologic findings with the clinical examination yielded the unexpected result that dysplasia and lesion size are independent of each other. Lesions 3 mm in diameter or smaller were as likely to be dysplastic as those much larger. There was, however, a statistically significant relationship between histologic dysplasia of a nevus examined by biopsy and the person's total number of melanocytic lesions. This finding indicates that the pathology grading scheme may be useful. The high prevalence of dysplastic nevi dilutes the clinical significance of a dysplastic nevus as an isolated finding and thereby lessens the importance of pathologic findings in the diagnosis of dysplastic nervus syndrome.

Adolescent↗

Linkage heterogeneity of autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease has been shown to be closely linked to the alpha-hemoglobin complex on the short arm of chromosome 16. We describe a five-generation kindred, descendants of Sicilian immigrants, in which the disease occurs but without linkage to the alpha-hemoglobin complex. DNA probes were used in genetic-linkage studies on blood samples from 163 family members, of whom 71 were affected by or at risk for autosomal dominant polycystic kidney disease. Diagnoses were confirmed by ultrasound examination. In this family the frequency of recombination between the alpha-hemoglobin complex and the region previously shown to contain the mutation causing polycystic kidney disease exceeded 24 percent, indicating a mutation at a different locus. The clinical findings in this family were indistinguishable from those in other families with polycystic kidney disease. We conclude that there is a second gene for autosomal dominant polycystic kidney disease. This apparent heterogeneity means that prenatal and presymptomatic diagnosis must be approached with caution until a method is found to distinguish between the two forms of the disease.

Adolescent↗