RESUMO
BACKGROUND: Researchers often relate personal experiences of difficulties and challenges with Institutional Review Board (IRB) review of their human genetic research protocols. However, there have been no studies that document the range and frequency of these concerns among researchers conducting human genetic/genomic studies. METHODS: An online anonymous survey was used to collect information from human genetic researchers regarding views about IRB review of genetic protocols. Logistic regression was used to test specific hypotheses. Results from the national online survey of 351 human genomic researchers are summarized in this report. RESULTS: Issues involving considerable discussion with IRBs included reconsent of subjects (51%), protection of participants' personal information (39%) and return of results to participants (34%). Over half of the participants had experienced one or more negative consequences of the IRB review process and approximately 25% had experienced one or more positive consequences. Respondents who had served on an IRB were about 80% more likely to report positive consequences of IRB review than their colleagues who had never served on an IRB (p = 0.03). Survey responses were mixed on the need for reconsent before data sharing and risks related to participant reidentification from genomic data. CONCLUSION: The results from this study provide important perspectives of researchers regarding genetic research review and show lack of consensus on key research ethics issues in genomic research.
Assuntos
Atitude , Comitês de Ética em Pesquisa , Pesquisa em Genética/ética , Genética/tendências , Consentimento Livre e Esclarecido , Bioética , Confidencialidade , Coleta de Dados , Feminino , Genômica , Humanos , Masculino , Privacidade , Análise de Regressão , Pesquisadores , SoftwareRESUMO
PURPOSE: The main purpose of this study was to determine if comprehension of the cancer risk information presented in a hypothetical report for BRCA1/2 gene analyses was influenced by the format in which the information was presented. A secondary objective was to determine physician characteristics that might influence comprehension of the report. METHODS: A survey was conducted in which a case vignette describing a young woman at high risk for carrying a BRCA mutation was presented. Survey participants, all primary care practitioners, were asked to interpret a laboratory report that provided the patient's BRCA1/2 test result and accompanying data about the cumulative risk and incidence rates of breast cancer for BRCA1/2 mutation carriers and the general population. These data were presented in the report in either a tabular or a graphic format. The main outcome was measured by the responses to four questions that addressed the probabilistic cancer risk information. Physician predictor variables included medical specialty, practice setting, years in practice, continuing medical education in genetics, and knowledge of cumulative risk. RESULTS: Knowledge of cumulative risk was the only physician variable that influenced comprehension of the cancer risk information (OR = 31.9; P < 0.001). After adjusting for this variable, the graphic format tended to perform better than the tabular format in conveying breast cancer risk information (OR = 3.1; P = 0.102). CONCLUSIONS: Many physicians may be unprepared to interpret genetic risk information, due to lack of understanding of basic epidemiologic terms used to express the risk of disease.
Assuntos
Neoplasias da Mama/genética , Competência Clínica , Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença , Testes Genéticos , Médicos de Família/normas , Adulto , Neoplasias da Mama/epidemiologia , Coleta de Dados , Medicina de Família e Comunidade/educação , Medicina de Família e Comunidade/normas , Feminino , Heterozigoto , Humanos , Incidência , Pessoa de Meia-Idade , Médicos de Família/educação , Médicos de Família/psicologia , Projetos Piloto , Padrões de Prática Médica/normas , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Siblings and other first-degree relatives of patients with "sporadic" (i.e., apparently nonfamilial) colorectal cancer or precursor adenomatous colon polyps have an increased risk of developing colon neoplasia. This observation suggests the presence of inherited genetic determinants for sporadic colon neoplasia. Mice homozygous for a null cyclooxygenase 2 (COX2) (also called PTGS2) allele have a dramatically reduced susceptibility to the development of intestinal adenomas. In humans, use of pharmacologic inhibitors of COX2 enzyme activity are associated with reduced risk of colon neoplasia. This study examined whether the human COX2 locus may be linked to colon neoplasia in humans. METHODS: We used the affected sibling-pair method to test for linkage of the human COX2 locus to colon neoplasia. RESULTS: We examined 74 concordantly affected sibling pairs from 46 sibships with colon neoplasia. One hundred five siblings from these sibships were diagnosed with either colorectal cancer or colon adenomatous polyps before age 65 years. No linkage between COX2 and colon neoplasia was found by use of a multipoint model-free linkage analysis (estimate of allele sharing was 0.44; standard error = +/-0.04; 95% confidence interval = 0.36 to 0.52). Moreover, even allowing for heterogeneity, the potential that a COX2 colon neoplasia susceptibility variant was present within a substantial subset of these sibships was strongly excluded under either a recessive or a dominant inheritance model (95% confidence to exclude a model in which 2.7% or more of the sibling pairs harbor a dominant susceptibility allele). CONCLUSIONS: This study of concordantly affected sibling pairs thus demonstrates that variations in the COX2 gene are unlikely to be a source of individual susceptibility to colon neoplasia in humans.
Assuntos
Neoplasias do Colo/genética , Isoenzimas/genética , Prostaglandina-Endoperóxido Sintases/genética , Polipose Adenomatosa do Colo/genética , Alelos , Neoplasias do Colo/enzimologia , Ciclo-Oxigenase 2 , Feminino , Ligação Genética , Predisposição Genética para Doença , Humanos , Masculino , Proteínas de Membrana , Pessoa de Meia-Idade , LinhagemRESUMO
OBJECTIVES: Fallopian tube carcinoma is similar to ovarian and peritoneal carcinoma with respect to histology, response to chemotherapy, and prognosis. BRCA germline mutations have been commonly reported in ovarian and peritoneal carcinoma but rarely in other gynecologic cancers. METHODS: A patient with fallopian tube carcinoma and a family history of ovarian carcinoma underwent genetic counseling and BRCA testing as did her daughter. RESULTS: The patient and her daughter were found to have a germline BRCA2 mutation. CONCLUSION: Like a family history of ovarian or peritoneal carcinoma, the occurrence of fallopian tube cancer should alert the clinician to the possibility of an abnormality in the breast cancer susceptibility 1 or 2 genes.
Assuntos
Carcinoma/genética , Neoplasias das Tubas Uterinas/genética , Mutação em Linhagem Germinativa , Proteínas de Neoplasias/genética , Fatores de Transcrição/genética , Proteína BRCA2 , Feminino , Aconselhamento Genético , Humanos , Pessoa de Meia-Idade , LinhagemRESUMO
PURPOSE: To identify characteristics of physicians, patients, and visits associated with obtaining family history information in community family practice. METHODS: Research nurses directly observed 4,454 patient visits to 138 family physicians and reviewed office medical records. RESULTS: Family history was discussed during 51% of visits by new patients and 22% of visits by established patients. Physicians' rates of family history-taking varied from 0% to 81% of visits. Family history was more often discussed at well care rather than illness visits. The average duration of family history discussions was <2.5 minutes. CONCLUSIONS: These data can form the basis for realistic interventions to increase the use of family history in primary care.
Assuntos
Saúde da Família , Medicina de Família e Comunidade/estatística & dados numéricos , Testes Genéticos , Anamnese/estatística & dados numéricos , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Serviços de Saúde Comunitária , Feminino , Humanos , Lactente , Recém-Nascido , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Atenção Primária à Saúde , Técnicas ReprodutivasRESUMO
Families with autosomal dominant inherited predisposition to gastric cancer have been described. More recently, germline E-cadherin/CDH1 mutations have been identified in hereditary diffuse gastric cancer kindred. The need to have protocols to manage and counsel these families in the clinic led a group of geneticists, gastroenterologists, surgeons, oncologists, pathologists, and molecular biologists to convene a workshop to produce consensus statements and guidelines for familial gastric cancer. Review of the available cancer pathology from people belonging to families with documented germline E-cadherin/CDH1 mutations confirmed that the gastric cancers were all of the diffuse type. Criteria to define the different types of familial gastric cancer syndromes were agreed. Foremost among these criteria was that review of histopathology should be part of the evaluation of any family with aggregation of gastric cancer cases. Guidelines for genetic testing and counselling in hereditary diffuse gastric cancer were produced. Finally, a proposed strategy for clinical management in families with high penetrance autosomal dominant predisposition to gastric cancer was defined.
Assuntos
Caderinas/genética , Neoplasias Gástricas/genética , Gastrectomia , Aconselhamento Genético , Predisposição Genética para Doença , Guias como Assunto , Humanos , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/cirurgia , Neoplasias Gástricas/terapiaRESUMO
To extend earlier observations of germline E-cadherin mutations in kindreds with an inherited susceptibility to diffuse gastric cancer, we searched for germline E-cadherin mutations in five further families affected predominantly by diffuse gastric cancer and one family with a history of diffuse gastric cancer and early-onset breast cancer. Heterozygous inactivating mutations were found in the E-cadherin gene in each of these families. No mutation hotspots were identified. These results demonstrate that germline mutation of the E-cadherin gene is a common cause of hereditary diffuse gastric cancer and suggest a role for these mutations in the incidence of breast cancer.
Assuntos
Adenocarcinoma/genética , Neoplasias da Mama/genética , Caderinas/genética , Mutação em Linhagem Germinativa , Neoplasias Gástricas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Mutacional de DNA , Feminino , Humanos , Leucócitos , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Genético , SíndromeAssuntos
Ansiedade/psicologia , Neoplasias da Mama/genética , Genes BRCA1/genética , Testes Genéticos/psicologia , Mulheres/psicologia , Viés , Neoplasias da Mama/sangue , Neoplasias da Mama/prevenção & controle , Demografia , Revelação , Predisposição Genética para Doença/prevenção & controle , Predisposição Genética para Doença/psicologia , Humanos , Judeus , Escala de Ansiedade Frente a Teste/estatística & dados numéricosAssuntos
Ética Médica , Testes Genéticos/normas , Neoplasias/genética , Guias de Prática Clínica como Assunto , Medição de Risco , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Dissidências e Disputas , Governo Federal , Triagem de Portadores Genéticos , Pesquisa em Genética , Testes Genéticos/economia , Testes Genéticos/psicologia , Processos Grupais , Humanos , Oncologia/normas , National Institutes of Health (U.S.) , Neoplasias/diagnóstico , Fatores de Risco , Sociedades Médicas , Estados UnidosAssuntos
Braço/patologia , Perna (Membro)/patologia , Neoplasias Abdominais/diagnóstico por imagem , Neoplasias Abdominais/prevenção & controle , Síndrome de Beckwith-Wiedemann/diagnóstico , Criança , Diagnóstico Diferencial , Transtornos do Crescimento/complicações , Transtornos do Crescimento/patologia , Humanos , Hipertrofia , Neoplasias Renais/complicações , Programas de Rastreamento , Neoplasias/complicações , Neoplasias Embrionárias de Células Germinativas/diagnóstico por imagem , Neoplasias Embrionárias de Células Germinativas/prevenção & controle , Neurofibromatoses/diagnóstico , Síndrome , Ultrassonografia , Tumor de Wilms/complicaçõesAssuntos
Neoplasias da Mama/etnologia , Neoplasias da Mama/genética , Genes BRCA1 , Testes Genéticos/normas , Judeus , Adulto , Biomarcadores Tumorais , Neoplasias da Mama/epidemiologia , Ética Médica , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Pesquisa sobre Serviços de Saúde , Humanos , Judeus/classificação , Pessoa de Meia-Idade , Linhagem , Fatores de Risco , Estados Unidos/epidemiologiaRESUMO
Little information is available about notifying individuals with a family history of cancer about their risk of cancer. With the recent identification of BRCA1, an important predisposition gene for breast and ovarian cancer, genetic testing is becoming available to high-risk women and their families. Some of these individuals, may not be aware of their family history and may be notified of their family history by medical personnel or biomedical investigators. This disclosure could be detrimental to the individual by changing their perception of risk, sense of privacy, or psychosocial well-being. Members of 544 breast cancer families are currently being contacted as part of an epidemiologic follow-up study at the University of Minnesota. Some family members were unaware of their relative's diagnosis and therefore, notification occurred when they were contacted by study personnel. To determine the impact of risk notification in this context, 376 male and female relatives of 160 breast cancer probands were surveyed to assess their prior knowledge of their family history of cancer, issues relating to study participation, and their concerns regarding the possibility of developing cancer. Following a telephone interview about family history, family members were administered a short, open-ended questionnaire. The majority of individuals (82%) were blood relatives of the proband and 71% were either first- or second-degree relatives. A proportion of blood relatives (24%) were not aware of their family history of breast cancer. More blood relatives (76%) than nonblood relatives (62%, P < 0.01) were aware of their family history. 43 respondents (12%) expressed specific concerns about participating in the large genetic follow-up study and 16 comments concerned privacy issues. Neither the reasons for participation nor an individual's concern about developing cancer was associated with gender of the respondent, relationship to the proband, or awareness of breast cancer in the family. Interestingly, individuals who were notified about their family history through the large follow-up study were no more likely than other family members to be more concerned about developing cancer. Understanding the privacy and psychosocial issues of family members who are informed about a family history of breast cancer may aid in developing appropriate guidelines for notification. Risk notification in this setting does not appear to have a significant impact on these family members.
Assuntos
Neoplasias da Mama/genética , Confidencialidade , Revelação , Aconselhamento Genético , Pesquisa em Genética , Estudos de Casos e Controles , Feminino , Marcadores Genéticos , Humanos , Masculino , Medição de Risco , Inquéritos e QuestionáriosRESUMO
There are recent data to suggest that risk factors for breast cancer may differ according to whether the tumor expresses detectable levels of the estrogen receptor (ER) and progesterone receptor (PR). While a family history of breast cancer is one of the most consistent predictors of the disease, we recently reported a modest inverse association with ER+PR- tumors. However, the definition of a family history of cancer did not consider second-degree relatives or cancer sites that may be etiologically related. The current report presents additional data analysis from the Iowa Women's Health Study, a prospective population-based cohort study conducted among 41,837 postmenopausal women. At baseline in 1986, respondents provided information on family history of cancers of the breast, ovaries, or uterus/endometrium in their mothers, sisters, daughters, maternal and paternal grandmothers, and maternal and paternal aunts. Data on family history of prostate cancer in fathers and brothers and age at onset of breast cancer in mothers and sisters were collected in 1992. Cohort members were followed for cancer incidence through the statewide tumor registry. After 7 years and more than 235,000 person-years of follow-up, 939 incident cases of breast cancer were identified. Information was obtained from the tumor registry on ER (+/-) and PR (+/-) status for 610 cases (65.0%). A family history of breast cancer in first-degree relatives was associated with increased risk (relative risk [PR] = 1.4; 95% confidence interval [CI]: 1.1-1.6) for all receptor-defined subtypes of breast cancer except ER+PR- tumors (RR = 0.7; 95% CI: 0.3-1.4). These results were unchanged when data on second-degree relatives were included. When the onset of breast cancer in relatives occurred at or before the age of 45 years, increased risks were evident only for ER-PR+ and ER-PR- tumors (RR = 2.3 and 3.3, respectively). Conversely, when relatives were affected with breast cancer after the age of 45 years, increased risks were most apparent for ER+PR+ and ER-PR+ tumors (RR = 1.3 and 3.2, respectively). A family history of prostate cancer in first-degree relatives was associated with a 1.2-fold increased risk of breast cancer (95% CI: 0.98-1.50), largely a reflection of the association with ER-PR- tumors (RR = 1.5; 95% CI: 0.8-3.0). The small numbers of cases in some categories and the corresponding wide CIs preclude definitive conclusions, but these data are at least suggestive that joint stratification of breast tumors on ER and PR status may be useful in partitioning breast cancer families into more homogeneous subsets.
Assuntos
Neoplasias da Mama/genética , Neoplasias/genética , Receptores de Estrogênio/genética , Receptores de Progesterona/genética , Adulto , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Neoplasias/metabolismo , Neoplasias Ovarianas/genética , Valor Preditivo dos Testes , Estudos Prospectivos , Neoplasias da Próstata/genética , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Fatores de Risco , Neoplasias Uterinas/genéticaRESUMO
The use of short tandem repeat polymorphisms (STRPs) as marker loci for linkage analysis is becoming increasingly important due to their large numbers in the human genome and their high degree of polymorphism. Fluorescence-based detection of the STRP pattern with an automated DNA sequencer has improved the efficiency of this technique by eliminating the need for radioactivity and producing a digitized autoradiogram-like image that can be used for computer analysis. In an effort to simplify the procedure and to reduce the cost of fluorescence STRP analysis, we have developed a technique known as multiplexing STRPs with tailed primers (MSTP) using primers that have a 19-bp extension, identical to the sequence of an M13 sequencing primer, on the 5' end of the forward primer in conjunction with multiplexing several primer pairs in a single polymerase chain reaction (PCR) amplification. The banding pattern is detected with the addition of the M13 primer-dye conjugate as the sole primer conjugated to the fluorescent dye, eliminating the need for direct conjugation of the infrared fluorescent dye to the STRP primers. The use of MSTP for linkage analysis greatly reduces the number of PCR reactions. Up to five primer pairs can be multiplexed together in the same reaction. At present, a set of 148 STRP markers spaced at an average genetic distance of 28 cM throughout the autosomal genome can be analyzed in 37 sets of multiplexed amplification reactions. We have automated the analysis of these patterns for linkage using software that both detects the STRP banding pattern and determines their sizes. This information can then be exported in a user-defined format from a database manager for linkage analysis.
Assuntos
Mapeamento Cromossômico , Primers do DNA , Corantes Fluorescentes , Raios Infravermelhos , Sequências Repetitivas de Ácido Nucleico/genética , Polimorfismo GenéticoRESUMO
In the past decade, significant progress has been made in understanding the genetic component of familial cancers. Genes associated with familial colon and breast cancers have recently been isolated and molecular diagnostic tests are expected to become available in the near future. Clinicians now have the opportunity to recognize and counsel individuals with elevated risk of cancer by identifying risk factors and genes associated with cancer predisposition. The rapid advances in molecular technology are a direct challenge to the medical community and cancer centers to supply specialized clinical services for familial cancers. We sought to ascertain the activities of cancer centers in the development of programs and the provision of genetic services for familial cancer. We surveyed 41 centers with National Cancer Institute (NCI) cancer center support grants. One half of the centers responding (17 of 34) reported that they provide some genetic services for familial cancer. About one half of these 17 centers (eight [57%] of 14; the three remaining clinics that responded had incomplete information on this indicator) see a variety of patient types on a small scale (fewer than 100 patients per year), and most provide four basic clinical evaluations: medical evaluation, cancer risk assessment, genetic counseling, and pedigree analysis. Staffing of each center varied widely, as did the types of screening services offered (including molecular diagnostic testing). Several centers (six [35%] of 17) indicated that they were in the developmental stages for serving familial cancer patients, and many seem to be increasing their activities in this area. The remaining 17 NCI-supported centers that responded, however, currently provide no genetic services for familial cancers. The results of this survey suggest that there is interest in developing clinical programs for familial cancers by NCI-supported cancer centers, but most of these programs are in developmental stages. A base line has been established to monitor future progress for the provision of cancer genetic services.
Assuntos
Institutos de Câncer/estatística & dados numéricos , Aconselhamento Genético/estatística & dados numéricos , Neoplasias/genética , Testes Genéticos , Humanos , Programas de Rastreamento , National Institutes of Health (U.S.) , Neoplasias/prevenção & controle , Inquéritos e Questionários , Estados UnidosRESUMO
Partial deletion of the short arm of chromosome 9 (p24-->pter) and partial duplication of the long arm of chromosome 5 (q32-->qter) were observed in an abnormal boy who died at age 8 weeks of a complex cyanotic cardiac defect. He also had minor anomalies, sagittal craniosynostosis, triphalangeal thumbs, hypospadias, and a bifid scrotum. Two other infants with similar cytogenetic abnormalities were described previously. These patients had severe congenital heart defect, genitourinary anomalies, broad nasal bridge, low hairline, apparently low-set ears, short neck, and triphalangeal thumbs, in common with our patient. We suggest that combined monosomy 9p23,24-->pter and trisomy 5q31,32-->qter may constitute a clinically recognizable syndrome.
Assuntos
Anormalidades Múltiplas/genética , Cromossomos Humanos Par 5 , Cromossomos Humanos Par 9 , Cardiopatias Congênitas/genética , Monossomia , Trissomia , Autopsia , Bandeamento Cromossômico , Mapeamento Cromossômico , Humanos , Recém-Nascido , Cariotipagem , Masculino , SíndromeRESUMO
Chromosome region 15q is thought to contain one or more genes that are important for melanin pigment synthesis in the hair, skin, and eyes. Hypopigmentation has been identified in the Prader-Willi (PWS) and Angelman (AS) syndromes. We have examined 6 individuals with AS to further characterize the pigment pattern in this condition. The age of the 5 girls and one boy ranged from 2.4 to 7.0 years. None had obvious albinism. Hair color ranged from light blond to brown. Skin was type I in 3 and type II in 3. Eye changes included nystagmus in 2, strabismus in 4, and reduced retinal pigment in 5. The mean hairbulb tyrosinase activity was 0.37 +/- 0.44 pmol/hb/120 min for the individuals with AS, with a range of 0.00 to 1.13 (normal brown control 1.49 +/- 0.79, normal blond control 1.50 +/- 0.85). Electron microscopic examination of hairbulb melanocytes showed normal melanosome and melanocyte architecture and number, but reduced melanin formation, with many stage II and III premelanosomes but few stage IV fully melanized melanosomes. Hypopigmentation characterized by light skin, reduced retinal pigment, low hairbulb tyrosinase activity, and incomplete melanization of melanosomes is part of the phenotype of AS, and is similar to that found in PWS.
Assuntos
Síndrome de Angelman , Hipopigmentação , Síndrome de Angelman/genética , Criança , Pré-Escolar , Cromossomos Humanos Par 15 , Cor de Olho , Feminino , Cabelo/enzimologia , Cabelo/metabolismo , Cabelo/ultraestrutura , Cor de Cabelo , Humanos , Hipopigmentação/genética , Masculino , Melaninas/biossíntese , Melanócitos/metabolismo , Melanócitos/ultraestrutura , Microscopia Eletrônica , Monofenol Mono-Oxigenase/análise , Monofenol Mono-Oxigenase/biossíntese , Pigmentação da PeleRESUMO
Cutaneous and ocular pigmentation were evaluated in 29 individuals with the Prader-Willi syndrome (PWS). Criteria for hypopigmentation included the presence of type I or II skin, the lightest skin type in the family by history, and iris translucency on globe transillumination. On the basis of these criteria, 48% of the PWS individuals were hypopigmented. The presence of hypopigmentation correlated with a small interstitial deletion on the proximal long arm of chromosome 15; however, this deletion was also found in individuals who did not meet the full criteria for hypopigmentation. Hairbulb tyrosinase activity and glutathione content, as well as urine cysteinyldopa excretion, were low in PWS individuals with and without hypopigmentation and did not separate these two groups. We conclude that hypopigmentation is found in a significant proportion of individuals with PWS and that the hypopigmentation may be associated with a deletion of the long arm of chromosome 15. The mechanism for the hypopigmentation is unknown.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 15 , Transtornos da Pigmentação/genética , Síndrome de Prader-Willi/genética , Cor de Olho , Cabelo/enzimologia , Cabelo/ultraestrutura , Cor de Cabelo , Humanos , Transtornos da Pigmentação/etiologia , Transtornos da Pigmentação/patologia , Síndrome de Prader-Willi/complicações , Síndrome de Prader-Willi/patologia , Pigmentação da PeleRESUMO
Patients with oculocutaneous or ocular albinism have misrouting of optic fibers, with fibers from 20 degrees or more of the temporal retina crossing at the chiasm instead of projecting to the ipsilateral hemisphere. Misrouting can result in strabismus and nystagmus. Because patients with the Prader-Willi syndrome may also have hypopigmentation and strabismus, we wondered whether they too might have misrouting of optic fibers. We therefore studied six patients with Prader-Willi syndrome selected for a history of strabismus, using pattern-onset visually evoked potentials with binocular and monocular stimulation to look for evidence of misrouted retinal-ganglion fibers. Four had hypopigmentation, and three of these four had abnormal evoked potentials indistinguishable from those recorded in human albinos. The two with normal pigmentation had normal responses. These findings indicate that patients with Prader-Willi syndrome who have hypopigmentation have a brain abnormality characterized by misrouting of retinal-ganglion fibers at the optic chiasm--a finding previously reported only in forms of albinism.