Caucasian family with two independent mutations: 2594delC in BRCA1 and 5392delAG in BRCA2 gene.

Germline mutations in two breast cancer susceptibility genes, BRCA1 and BRCA2, predispose individuals to early onset breast and ovarian cancer. The frequency of mutations in these genes in the general population is very low. Therefore, the prior probability of finding any family with mutations in both genes is even lower. This study reports the presence of two mutations, one in BRCA1 and a second in BRCA2, in a single family with variable expression. The BRCA1 mutation, 2594delC, was identified first in the proband. Analysis on a related family member with early onset bilateral breast cancer for the same mutation was negative. Further analysis on the same individual led to the identification of a second germline mutation, 5392delAG in BRCA2 gene in this family. Without the knowledge of the second mutation in this family, many asymptomatic individuals would have been given a negative test result and be falsely reassured. Further analysis reveals differential expression of the two mutations. The spectrum of cancers as well as the age of onset is variable between the mutations and the generations. Finally, the study exemplifies the fact that molecular analysis of a genetically heterogeneous disease can be very complex and requires a team effort of the patients and their family members, genetic counselors or referring physicians as well as the personnel from the testing laboratory.

Commercialization of BRCA1/2 testing: practitioner awareness and use of a new genetic test.

It was our purpose to determine the characteristics of practitioners in the United States who were among the first to inquire about and use the BRCA1 and BRCA2 (BRCA1/2) genetic tests outside of a research protocol. Questionnaires were mailed to all practitioners who requested information on or ordered a BRCA1/2 test from the University of Pennsylvania (UPenn) Genetic Diagnostics Laboratory (GDL) between October 1, 1995 and January 1, 1997 (the first 15 months the test was available for clinical use). The response rate was 67% of practitioners; 54% (121/225) were genetic counselors, 39% (87/225) were physicians or lab directors. Most physicians were oncologists, pathologists, or obstetrician/gynecologists, but 20% practiced surgery or internal or general medicine. Fifty-six percent (125/225) had ordered a BRCA1/2 test for a patient; most of the rest had offered or were willing to offer testing. Of those who had offered testing, 70% had a patient decline BRCA1/2 testing when offered. Practitioners perceived that patients' fear of loss of confidentiality was a major reason for declining. Nearly 60% of practitioners reported that their patients had access to a genetic counselor, but 28% of physicians who ordered a BRCA1/2 test reported having no such access, despite the GDL's counseling requirement. The proportion of physicians reporting no access to genetic counselors for their patients increased from 22.4% in the first half of the study to 50% in the last half. Many practitioners have an interest in BRCA1/2 testing, despite policy statements that discourage its use outside of research protocols. Practitioner responses suggest that patient interest in testing seems to be tempered by knowledge of potential risks. An apparent increase in patient concern about confidentiality and inability to pay for testing could indicate growing barriers to testing. Although most practitioners reported having access to counseling facilities, perceived lack of such access among an increasing proportion of practitioners indicates that lab requirements for counseling are difficult to enforce and suggests that an increasing proportion of patients may not be getting access to counseling.

High throughput fluorescence-based conformation-sensitive gel electrophoresis (F-CSGE) identifies six unique BRCA2 mutations and an overall low incidence of BRCA2 mutations in high-risk BRCA1-negative breast cancer families.

Mutational analysis of cancer susceptibility genes has opened up a new era in clinical genetics. In this report we present the results of mutational analysis of the BRCA2 coding sequences in 105 high-risk individuals affected with breast cancer and/or ovarian cancer and previously found to be negative for mutations of the BRCA1 coding sequence in our laboratory. These individuals have a positive family history with three or more cases of breast cancer and/or ovarian cancer at any age from the same side of the family tree. In order to perform a high throughput and reliable mutational analysis of the BRCA genes, we have adapted the conformation-sensitive gel electrophoresis mutation-scanning assay to a fluorescent platform. The advantages are speed, reproducibility and enhanced resolving power of the scanning method. Four unique mutations, including one missense and three frameshift mutations, were identified in the pool of 60 non-Jewish patients (7%). Two cases of the 6174delT mutation were identified in the 45 Ashkenazi Jewish individuals studied (5%). In addition, two novel frameshift mutations, not characteristic of the Jewish subgroup, were identified. Thus there were four mutations in total in this ethnic subgroup (9%). The six mutations identified in this combined patient pool, excluding the 6174delT mutations, are novel and have not been previously reported in the Breast Cancer Information Core (BIC) database. The results indicate that BRCA2 mutations account for the disease in less than 10% of this patient population. In addition, there is no significant difference in frequency of BRCA2 mutations between the Ashkenazi Jewish and non-Jewish families in our clinical patient pool.

Genetic testing for breast cancer susceptibility: frequency of BRCA1 and BRCA2 mutations.

Genetic testing for breast cancer susceptibility became a reality after two cancer predisposition genes, BRCA1 and BRCA2, were identified. Mutations in these two genes were predicted to account for 85% to 90% of hereditary breast and ovarian cancer syndromes. We present results of mutation analysis of the coding sequence of these two genes in 110 consecutive non-Jewish breast cancer patients with a positive family history of breast and/or ovarian cancer. The individuals were identified in various cancer risk evaluation centers in the country. Twenty-two (20%) mutations in the BRCA1 gene and 8 mutations (7%) in the BRCA2 gene were detected. We also analyzed 52 Ashkenazi Jewish breast cancer patients for mutations in the BRCA1 and BRCA2 genes. Eleven Jewish individuals (21%) carried either one of the two common mutations, 185delAG and 5382InsC, in the BRCA1 gene and 4 individuals (8%) had the 6174delT mutation in the BRCA2 gene. The frequency of mutations in BRCA genes in affected people in this ethnic group was not significantly different from the non-Jewish population. On further analysis, the data demonstrate that neither age of onset nor phenotype of the disease had any significant predictive value for the frequency of mutations in these genes. These data confirm the lower prevalence of mutations in either of the BRCA genes in clinical families when compared to high-risk families used for obtaining linkage data in a research setting.

Ultrasound-adjusted risk and spectrum of fetal chromosomal abnormality in women with elevated maternal serum alpha-fetoprotein.

OBJECTIVE: To determine the incidence of chromosomal abnormality in sonographically normal fetuses after amniocentesis for elevated maternal serum alpha-fetoprotein (MSAFP), and to compare the spectrum of abnormality with that seen in women undergoing amniocentesis for advanced maternal age. METHODS: Cytogenetic and sonographic findings from women undergoing amniocentesis for elevated MSAFP (at least 2.0 multiples of median) between 1988-1992 were reviewed retrospectively. The literature was reviewed and data compiled regarding the risk of chromosomal abnormality for women with elevated MSAFP levels. RESULTS: The incidence of abnormal karyotype among all women with elevated MSAFP was 1.23% (nine of 733). The risk of an abnormal karyotype with a normal ultrasound examination was 1.01% (seven of 696). This included three fetuses with sex chromosome abnormalities, three with de novo, apparently balanced rearrangements, and one with an unbalanced structural rearrangement. CONCLUSIONS: The risk of chromosomal abnormality in nonselected patients, predominantly younger than 35 years of age, with elevated MSAFP and a sonographically normal fetus is 0.6%, based on a compilation of our data and reports published previously. The spectrum of abnormality in women with elevated MSAFP differs from that in women of advanced maternal age. Patients should be specifically counseled regarding this difference.

Significance of sonographically detected second-trimester choroid plexus cysts: a series of 211 cases and a review of the literature.

A retrospective analysis of all fetuses with prenatally detected choroid plexus cysts, identified at our institution between 1988 and 1993, was performed. Cytogenetic data, associated sonographic findings, obstetric outcome and pediatric follow-up was obtained to determine the incidence of aneuploidy and the rate of associated congenital anomalies in second-trimester fetuses with this finding. There were 211 second-trimester fetuses identified with a choroid plexus cyst. Amniocentesis was performed in 175 (83%) and postnatal chromosome analysis was performed in one newborn. Follow-up data are available on 203 (96%). Of the 176 cytogenetically studied fetuses, eight (4.5%) were aneuploid (including four cases of trisomy 18). In four of the aneuploid fetuses, the choroid plexus cyst was the only abnormal sonographic finding identified (including one case of trisomy 18). From this study and a review of the literature, we confirm that choroid plexus cysts are a sonographic marker for trisomy 18, even when identified as an isolated finding in an otherwise normal-appearing fetus. We conclude that the detection of a choroid plexus cyst merits further careful evaluation of fetal anatomy and consideration of cytogenetic evaluation.

Chorionic villus sampling utilization following reports of a possible association with fetal limb defects.

Prenatal diagnosis choices were reviewed in 473 women who presented for genetic counselling prior to 11 weeks' gestation for the indication of advanced maternal age. Group A consisted of 336 patients who were unaware of a possible association between chorionic villus sampling (CVS) and limb defects. Group B consisted of 137 patients who were provided this information. Fifty-one per cent of patients in group A and 45 per cent of patients in group B chose CVS. This difference was not significant by chi 2 analysis (P = 0.7). Patterns of prenatal diagnosis procedure utilization from 1987 to 1992 revealed a significant reduction in CVS utilization accompanied by a corresponding increase in amniocentesis after the association between CVS and limb defects was publicized. Referrals for CVS counselling also significantly declined. However, acceptance rates did not change for those patients who received genetic counselling. First-trimester genetic counselling, including a discussion regarding a possible association between CVS and limb defects, helps patients make informed decisions concerning prenatal diagnosis options, and, in our population, resulted in no change in CVS acceptance rates.

Acute hemodynamic effects induced by chorionic villus sampling: a preliminary investigation.

OBJECTIVE: Our purpose was to evaluate the effects of chorionic villus sampling on the fetal heart rate, the fetal umbilical artery pulsatility index, and the maternal arcuate artery resistance index. STUDY DESIGN: M-mode fetal heart rate, pulsed Doppler fetal umbilical artery pulsatility index, and maternal arcuate artery resistance index measurements were obtained before and immediately after chorionic villus sampling in 50 patients and were compared with 50 procedure-free, gestational age--matched controls. Comparisons within groups were performed with paired T tests and mean changes between groups with two-sample T tests, and variance comparisons between groups were performed with F tests. RESULTS: The mean changes (SD) in fetal heart rate, umbilical artery pulsatility index, and arcuate artery resistance index in patients undergoing chorionic villus sampling and in controls were not statistically different from zero or from each other. However, the variance around the mean fetal heart rate change was 17.1 times larger in the chorionic villus sampling group than the control group (F 17.1, degrees of freedom 49,49, p < 0.0001), and the variance around the mean pulsatility index change was 2.7 times larger in the chorionic villus sampling group than in the control group (F 2.7, degrees of freedom 49,49, p = 0.0007). There was no significant difference in mean resistance index change or variance around the mean resistance index change between groups. CONCLUSION: Chorionic villus sampling induces significant but unpredictable fluctuations in fetal heart rate and umbilical artery pulsatility index but does not affect maternal arcuate artery resistance index.

Chorionic villus sampling followed by amniocentesis in the same pregnancy.

In our consecutive series of 2,574 chorionic villus sampling (CVS) patients, 146 women (5.7%) underwent a subsequent amniocentesis in the same pregnancy for the indications of absent or insufficient villi (3.3%), elevated maternal serum alpha-fetoprotein (0.93%), CVS mosaicism (0.89%), culture failure (0.23%), specimen contamination (0.15%), and CVS aneuploidy (0.12%). Patients presenting for a CVS should be informed of the possible need for a subsequent amniocentesis in the same pregnancy. There is a need for individual prenatal diagnosis programs to analyze their own data and provide genetic counseling information which pertains specifically to their institution.

Prenatal diagnosis of Fraser syndrome at 18.5 weeks gestation, with autopsy findings at 19 weeks.

Sonography permitted the diagnosis of Fraser syndrome (cryptophthalmos-syndactyly syndrome) at 18.5 weeks of gestation in a fetus whose parents had had a previous affected child. The karyotype of that child was 46,XX,inv(9)(p11q21); the karyotype of the phenotypically normal father and of the fetus was 46,XY,inv(9)(p11q21). Findings on sonography included oligohydramnios with nonvisualization of kidneys, hypertelorism and microphthalmia, and markedly enlarged lungs. On autopsy at 19 weeks, findings included renal agenesis, cryptophthalmos with multiple abnormalities of the eyes and ocular adnexa, laryngeal atresia, pulmonary hyperplasia with accelerated maturation, absence of the Eustachian tube with connective tissue occupying the tympanic cavity and bone occluding the external acoustic meatus, and soft-tissue webbing between the digits. This is the second reported instance of prenatal diagnosis of Fraser syndrome in the second trimester. The histopathologic findings in Fraser syndrome at this gestational age, in particular the eye and ear, have not been described previously.

Genetic amniocentesis at 14 weeks or less.

The recent clinical trials indicate that EA is feasible. The use of ancillary tools, such as ultrasound, requires only a slight modification of the previously established techniques for MA. The amniotic fluid can be obtained and cultured. Combining the reported populations sampled, the procedural and cytogenetic failure rate were 2.0% and 0.3% respectively. The necessary information for prenatal diagnosis in the situations listed previously can be obtained. The one exception to this would be the patient at increased risk for NTD. As noted above, diagnostic levels for AFAFP have been established beginning at 13 weeks gestation. Therefore, amniocentesis before 13 weeks gestation should not be considered an option for these patients. The majority of the findings in these "pilot" studies have been promising, but the issue regarding the safety of EA has not been answered. Harrison et al. theorized that the function of the physiology hydramnios was to "provide a distention growth stimulus to the uterus ... and conversely to share in the maintenance of uterine inhibition." The amniotic fluid is constantly being replaced, having a complete turnover approximately every 3 hours. Does the reduction in volume, for even a short period of time, change the "distensive forces" enough to increase the pregnancy loss rate? Later publications have associated MA with increased rates of congenital orthopedic anomalies and neonatal pulmonary compromise. The true existence of these complications continues to be debated in the literature. Two of the authors have indicated that none of the reported neonates exposed to EA have had such anomalies.(ABSTRACT TRUNCATED AT 250 WORDS)

Prenatal genetic diagnosis in a triplet gestation.

The increasing incidence of multiple gestations and the need for genetic diagnosis often pose a question as to the safety of amniocentesis in these cases. Under careful sonographic control and using indigo carmine as a marker, a technique for amniocentesis in a triplet gestation is presented.

Analysis of a follow-up study of genetic counseling.

A follow-up study of 212 families for whom genetic counseling had been provided was performed to assess the effectiveness of the non-directive genetic counseling service at the Mount Sinai Medical Center in New York City. The preliminary result have been reported previously (Godmilow & Hirschhorn 1977). Of those families surveyed, 72% responded. Adequate recall of the genetic information was demonstrated by 74% of those responding, and 80% described their counseling experience as favorable. A direct relationship was noted between the degree of satisfaction and whether or not the counselees received the mode of counseling they preferred, i.e., individual versus team. Sixty-two percent of those counselees reaching a procreative decision indicated that genetic counseling had influenced their decision making. A significant correlation was noted between the magnitude of the occurrence or recurrence risk and the procreative decisions reached. However, some decisions were modified by the counselees' subjective interpretation of the burden associated with the disorder in question. It is concluded that follow-up of genetic counseling by questionnaire, together with statistical analysis of the data received, can provide the genetic center with valuable information regarding strengths and weaknesses of the counseling program and can suggest ways to improve the counseling process and thereby enhance its effectiveness.

PIP: 212 families counseled at the genetic clinics a between 1970 and 1975 were followed up to measure the success of nondirective genetic counseling service offered by the Mt. Sinai Medical Center in New York and to identify areas of difficulty of the program. 83% of the families were white, 15% were Hispanic and 2% were black. Most of the families desired to have additional children (most already had 1 child with a possibly inherited disorder). Written questionnaires were sent to the families, 72% of whom responded. 74% of the respondents had adequate recall of genetic information, and 80% stated that their counseling experience was favorable. A direct relationship was observed between degree of satisfaction and whether or not counselors received the mode of counseling they preferred (e.g., individual vs. team). 62% who decided to have another child reported that their decision was influenced by genetic counseling. Magnitude of occurrence/recurrence risk significantly correlated with procreative decision reached. Procreative decisions however were modified somewhat by the counselor's subjective interpretation of burden associated with the disorder in question. Follow-up studies of genetic counseling programs are informative and should be made an integral part of genetic counseling.

Prenatal cytogenetic diagnosis: first 1,000 successful cases.

From February 1969 to August 1976, we studied 1,048 amniotic fluids. Of these, 958 (91.4%) were primarily for prenatal cytogenetic diagnosis. Cytogenetic studies were attempted in 1,021 cases; the diagnosis was successful in 1,000 of these. The failure rate of obtaining a diagnosis from the amniotic fluid cell culture of the first amniocentesis was 5% (50 cases); 29 cases had a repeat tap and successful diagnosis was achieved in all. In 21 cases, a repeat tap was refused. Thus, the overall failure rate of obtaining a final cytogenetic diagnosis was 2.06% (21/1,021). There were 32 fetal losses after amniocentesis including 16 spontaneous second trimester abortions, 7 fetal deaths in utero and 9 stillbirths. In two additional cases, fetal death had occurred before amniocentesis. This number of fetal losses does not exceed the number that would be expected in the same maternal age group without amniocentesis. In our series, the frequencies of trisomy in maternal age groups 40 years and over, 37-39 years, 35-36 years, and under 35 years were 4.5, 3.14, 0 and 0% respectively. These frequencies are comparable to those reported from other prospective prenatal studies and higher than those of retrospective live born studies. Various problems and pitfalls in prenatal cytogenetic diagnosis are discussed.

Prenatal diagnosis of bilateral renal agenesis.

Bilateral renal agenesis (BRA), or Potter's syndrome, is a rare genetic disorder in which agenesis of the kidneys is associated with pulmonary hypoplasia and characteristic facial features. Oligohydramnios or virtual absence of amniotic fluid is found in most pregnancies with BRA. Clinical observation and serial ultrasonography scans made it possible to diagnose BRA prenatally in a fetus at risk. Postmortem examination confirmed the diagnosis.

Prenatal diagnosis of renal anomalies.

Within the past 24 months, we have performed prenatal diagnostic studies in 4 pregnancies known to be at risk for well-described genetic syndrome involving renal abnormalities, ie, Meckel syndrome, Roberts syndrome, and bilateral renal agenesis. The diagnostic techniques utilized were ultrasonographic scanning (B-mode and grey scale), biochemical assays, and radiographic evaluation. The ultrasound finding common to the 3 affected cases was extreme oligohydramnios, which we considered indirect evidence that renal anomalies were present. The ultrasound scans of the fetuses affected with Meckel and Roberts syndrome demonstrated anechoic cystic spaces in the abdomen, representing the enlarged dysplastic cystic kidneys. An encephalocele was well demonstrated by B-mode scan in the fetus with Meckel syndrome. The absence of normal limbs in the Roberts syndrome was evident on serial grey scale scans of the fetus. Biochemical and radiographic studies provided results consistent with the suspected diagnoses. The importance of providing genetic counseling and prenatal diagnosis to families at risk is emphasized.