Integrating genetic and genomic information into effective cancer care in diverse populations.

This paper provides an overview of issues in the integration of genetic (related to hereditary DNA) and genomic (related to genes and their functions) information in cancer care for individuals and families who are part of health care systems worldwide, from low to high resourced. National and regional cancer plans have the potential to integrate genetic and genomic information with a goal of identifying and helping individuals and families with and at risk of cancer. Healthcare professionals and the public have the opportunity to increase their genetic literacy and communication about cancer family history to enhance cancer control, prevention, and tailored therapies.

Myoclonus-dystonia and Silver-Russell syndrome resulting from maternal uniparental disomy of chromosome 7.

Myoclonus-dystonia (M-D) is a movement disorder that is often associated with mutations in epsilon-sarcoglycan (SGCE), a maternally imprinted gene at 7q21.3. We report a 24-year-old male with short stature (<5th percentile) and a movement disorder clinically consistent with M-D. Single nucleotide polymorphism (SNP) array did not identify significant copy number changes, but revealed three long continuous stretches of homozygosity on chromosome 7 suggestive of uniparental disomy. Parental SNP arrays confirmed that the proband had maternal uniparental disomy of chromosome 7 (mUPD7) with regions of heterodisomy and isodisomy. mUPD7 is the cause of approximately 5-10% of Silver-Russell syndrome (SRS), a disorder characterized by prenatal and postnatal growth retardation. Although SRS was not suspected in our patient, these findings explain his short stature. SGCE methylation testing showed loss of the unmethylated paternal allele. Our findings provide a unifying diagnosis for his short stature and M-D and help to optimize his medication regimen. In conclusion, we show that M-D is a clinical feature that may be associated with SRS due to mUPD7. Individuals with mUPD7 should be monitored for the development of movement disorders. Conversely, individuals with M-D and short stature should be evaluated for SRS.

A 1.5 million-base pair inversion polymorphism in families with Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS) is most often caused by hemizygous deletion of a 1.5-Mb interval encompassing at least 17 genes at 7q11.23 (refs. 1,2). As with many other haploinsufficiency diseases, the mechanism underlying the WBS deletion is thought to be unequal meiotic recombination, probably mediated by the highly homologous DNA that flanks the commonly deleted region. Here, we report the use of interphase fluorescence in situ hybridization (FISH) and pulsed-field gel electrophoresis (PFGE) to identify a genomic polymorphism in families with WBS, consisting of an inversion of the WBS region. We have observed that the inversion is hemizygous in 3 of 11 (27%) atypical affected individuals who show a subset of the WBS phenotypic spectrum but do not carry the typical WBS microdeletion. Two of these individuals also have a parent who carries the inversion. In addition, in 4 of 12 (33%) families with a proband carrying the WBS deletion, we observed the inversion exclusively in the parent transmitting the disease-related chromosome. These results suggest the presence of a newly identified genomic variant within the population that may be associated with the disease. It may result in predisposition to primarily WBS-causing microdeletions, but may also cause translocations and inversions.

Whole genomewide linkage screen for neural tube defects reveals regions of interest on chromosomes 7 and 10.

Neural tube defects (NTDs) are the second most common birth defects (1 in 1000 live births) in the world. Periconceptional maternal folate supplementation reduces NTD risk by 50-70%; however, studies of folate related and other developmental genes in humans have failed to definitively identify a major causal gene for NTD. The aetiology of NTDs remains unknown and both genetic and environmental factors are implicated. We present findings from a microsatellite based screen of 44 multiplex pedigrees ascertained through the NTD Collaborative Group. For the linkage analysis, we defined our phenotype narrowly by considering individuals with a lumbosacral level myelomeningocele as affected, then we expanded the phenotype to include all types of NTDs. Two point parametric analyses were performed using VITESSE and HOMOG. Multipoint parametric and nonparametric analyses were performed using ALLEGRO. Initial results identified chromosomes 7 and 10, both with maximum parametric multipoint lod scores (Mlod) >2.0. Chromosome 7 produced the highest score in the 24 cM interval between D7S3056 and D7S3051 (parametric Mlod 2.45; nonparametric Mlod 1.89). Further investigation demonstrated that results on chromosome 7 were being primarily driven by a single large pedigree (parametric Mlod 2.40). When this family was removed from analysis, chromosome 10 was the most interesting region, with a peak Mlod of 2.25 at D10S1731. Based on mouse human synteny, two candidate genes (Meox2, Twist1) were identified on chromosome 7. A review of public databases revealed three biologically plausible candidates (FGFR2, GFRA1, Pax2) on chromosome 10. The results from this screen provide valuable positional data for prioritisation of candidate gene assessment in future studies of NTDs.

Ethical considerations in oncology: balancing the interests of patients, oncologists, and society.

BACKGROUND: Oncologists face ethical dilemmas every day in deciding about choice of treatment, continuation of treatments, events near the end of life, conflicts of interest, and risk management. Yet, many oncologists have limited training in ethics. METHODS: Review of existing studies and definitions of useful terms. Case studies analyzed according to ethical principles. RESULTS: Individual oncology cases can be analyzed according to ethical principles with benefit to the patient, physician, and possibly society. Ethics cannot resolve many of the thorny questions about allocation of resources, justice, or possible conflict of interest. CONCLUSION: Oncology decision-making fits into formal ethical frameworks, and understanding both can help doctors and patients make difficult choices. Understanding of ethical principles can help daily practice, but does not solve current dilemmas of allocation of resources, unrealistic demands, etc. More formal collaboration between hospital ethics committees or personnel and clinical oncologists is recommended for the day-to-day decision-making process.

Aortic stiffness: a new Doppler echocardiographic measure predictive of systolic blood pressure in children.

Aortic stiffness, the maximal frequency shift in the descending aorta divided by the Doppler acceleration time, was studied in 384 eleven year old twin children. The extent to which this measurement provided a prediction of systolic blood pressure that was independent of body size, heart rate, cardiac contractility and left ventricular mass was investigated. Aortic stiffness, after adjustment for height and weight, correlated significantly with systolic blood pressure (r = 0.22, p less than 0.01), but not with diastolic blood pressure. The short- (r = 0.82) and longer- (r = 0.68) term reproducibility of aortic stiffness was high. This measure appears to be a more powerful predictor of systolic blood pressure than is left ventricular mass. Aortic stiffness is a highly reproducible Doppler variable that may explain in part the contribution of the aortic wall elastic properties to the level of systolic blood pressure in preadolescent children at rest.

High-density lipoprotein-cholesterol subfractions in adolescent twins.

Data on the levels of high-density lipoprotein-cholesterol (HDL-C) and subfractions in 102 adolescent twin pairs and their parents are presented. Children with a family history of premature cardiovascular death had lower levels of HDL2-C than did those without such a history. White girls reporting a high level of physical activity had higher levels of HDL-C and HDL2-C than did their more sedentary peers. In general, children of mothers who smoked had lower HDL2-C than did children of nonsmoking mothers. These findings suggest that low levels of HDL2-C in children may identify families in which there is an increased risk of coronary heart disease and that parental smoking may contribute to changes in this risk factor in the children of smokers as well as in the smokers themselves.

Univariate genetic analysis of blood pressure in children (the Medical College of Virginia Twin Study).

The relative contributions of genetic, individual environmental and shared environmental effects on resting blood pressure (BP) and heart rate (HR) were studied in prepubescent twins. The study population consisted of 251 caucasian 11-year-old twin pairs. Correlations were higher for all variables in monozygotic twins compared to dizygotic twins; this is consistent with a significant genetic effect. Path analysis revealed that the model of additive genetic and individual environmental effects fit systolic BP, diastolic BP and HR. In boys and girls, sex-specific genetic effects controlled systolic BP. The magnitudes of the sex-specific genetic effects on systolic BP were similar in both boys and girls and accounted for 66% of the variance. In boys, for diastolic BP, genetic effects accounted for 64% of the variance while in girls they accounted for 51%. These results provide no evidence for different genetic effects on HR in boys or girls. No shared environmental effects were detected. The large sample size and design, using different-sex dizygotic twins of the same age, establish that genes play an important role in the influence of resting BP and HR and that there are sex-specific genetic contributions in early pubertal children.

Report of another family with Simpson-Golabi-Behmel syndrome and a review of the literature.

Simpson-Golabi-Behmel Syndrome (SGBS), an X-linked encephalo-tropho-schisis syndrome described in fewer than a dozen families, is characterized by pre- and postnatal overgrowth, "coarse" face, minor facial anomalies and, in more severe cases, multiple congenital anomalies and mental retardation. We report on 2 brothers with overgrowth, macrocephaly, polydactyly, supernumerary nipples, and characteristic facial appearance. In addition, the propositus also had pulmonic stenosis and a cleft palate. The findings present in our patients are compared to those in the original patients and to those in patients described more recently. Despite the fact that our patients have most of the minor and several of the more severe malformations, they are not mentally retarded.

Goldenhar complex in discordant monozygotic twins: a case report and review of the literature.

In 1952, Goldenhar described a pair of monozygotic twins who were discordant for epibulbar dermoids, auricular appendages, malformations of the auricle, and hemifacial microsomia. Eighteen twin pairs have subsequently been described in which at least one member exhibited these manifestations. We report on an additional pair of discordant dichorionic monozygotic male twins. All of the 5 monozygotic twin pairs for which placental information is available have been discordant and 2 of these had dichorionic membranes. The failure of discordant monozygotic twins to be limited to monochorionic pairs argues against the hypothesis that developmental abnormalities arising from the placental vascular anastomoses that are commonly found in monozygotic twins is the probable explanation for the discordant expression of these traits in twins.

Monozygotic twins discordant for Ullrich-Turner syndrome.

We describe 9-year-old twin girls who were thought to be monozygotic but who differed greatly in physical appearance and growth pattern. One twin had Ullrich-Turner syndrome (UTS), 45,X/46,XX mosaicism in peripheral blood, and only 45,X cells in skin fibroblasts. The phenotypically normal twin also had 45,X/46,XX mosaicism in blood but only 46,XX cells in cultured fibroblasts. Analysis of DNA marker patterns in blood lymphocytes and in skin fibroblasts confirmed monozygosity with a probability of 99.97%. This case is compared with other reported cases of discordance for UTS in twins. It is concluded that essentially all of the differences between the two twins can be explained by loss of an X chromosome early in embryogenesis with complete separation of 45,X and 46,XX cell lineages at the time of the twinning event. The presence of mosaicism in the peripheral blood of both twins is presumably due to anastomoses between the placentae resulting in a mixture of the two cell populations in the hematopoietic tissue.

Progressive bilateral nasal alar collapse: a dominantly inherited trait.

We describe a 47-year-old woman with progressive bilateral collapse of the alae nasi first noted at age 16 years. Her dizygotic twin daughters have similar nasal collapse beginning at age 20 years. This condition appears to be inherited as a dominant trait. Although plastic surgical correction has been successful for a phenotypically similar condition due to trauma, surgical correction must be considered cautiously in individuals with an atraumative, possibly inherited, progressive form of the disorder.

Ophthalmo-acromelic syndrome: report and review.

The ophthalmo-acromelic syndrome of Waardenburg is an autosomal recessive trait comprising eye malformations ranging from true anophthalmia to mild microphthalmia with acromelic malformations. Some 29 affected individuals have been reported since Waardenburg's first report in 1935 [Waardenburg et al., 1961]. We report on a new case with bilateral anophthalmia and typical limb malformations. The patient also was found to have interruption of the inferior vena cava with azygos continuation as an additional finding. The previous reports are reviewed to elucidate the spectrum of the syndrome.

Coffin-Siris syndrome: review and presentation of new cases from a questionnaire study.

To clarify the phenotypic variability of Coffin-Siris syndrome, we present a review of the literature and 18 new cases. We performed a questionnaire study of patients ascertained through an international support group. Information on their sibs was available for comparison. The most frequent findings include some degree of mental retardation or developmental delay, "coarse" facial appearance, feeding difficulties, frequent infections, and hypoplastic to absent fifth fingernails and fifth distal phalanges. We discuss the key manifestations for diagnosis, medical and developmental implications, and possible pathogenesis.

Updating McKusick: an educational exercise for medical students.

An educational module is described in which first-year medical students were assigned different entries from the 1983 edition of McKusick's Mendelian Inheritance in Man to revise and update. Following review and discussion in small group sections, the entries were reproduced to provide each student with an updated compendium of the selected genetic disorders. The important principles of Mendelian inheritance could be readily illustrated by the entities assigned to each discussion group. Students learned to use the library and how to understand and integrate clinical and experimental papers. More than half the students reported spending 11-20 h to complete the assignment and reviewed from six to ten articles in detail. The caliber of the entries was found to be significantly correlated with the time students reported they spend on the exercise, but not with the number of papers reviewed, prior knowledge of the disease entity, the frequency of dictionary usage, or undergraduate exposure to genetics.

Evidence for a major gene in familial anencephaly.

A 21-year-old white woman sought counseling after the birth of two consecutive anencephalic male fetuses with complete rachischisis and discordant renal dysplasia. The presence of parental consanguinity prompted reconsideration of recessive inheritance. The segregation ratio from 23 additional consanguineous cases was compared with that observed in 294 presumably nonconsanguineous families previously reported. Using classical segregation analysis, the segregation ratios in the non-sporadic cases were consistent with a major autosomal recessive locus in both populations.

Femoral duplication: a case report.

Femoral duplication is a rare anomaly that has been described as an isolated entity and in association with other congenital defects. Since the description by Erlich in 1885, 24 additional cases have been reported. The present report concerns a 34-week black female infant with apparent bilateral femoral duplication associated with a meningocele and abdominal, genitourinary, vertebral, and lower-limb anomalies. The cause is unknown. Femoral duplication is a developmental field defect, hence causally heterogeneous.

Fluorescence in situ hybridization detectable mosaicism for Angelman syndrome with biparental methylation.

We present a child with mild to moderate global developmental delay including severe speech impairment, inappropriate happy demeanor, wide-based gait, frequent ear infections with mild hearing loss, deep-set eyes, a wide mouth, widely-spaced teeth, normal head circumference, and no seizures. Results of peripheral blood lymphocyte chromosomal analysis with GTG banding were normal. However, fluorescence in situ hybridization (FISH) studies showed mosaicism for a deletion of probes (D15S10 and SNRPN) from the Angelman syndrome (AS) critical region with approximately 40% of peripheral lymphocytes having the deletion. The deleted chromosome 15 also showed centromeric duplication, which was detected with a D15Z1 probe [46,XX, dic(15)(pter-->q11.1::p11.2-->q11. 1::q13-->qter)]. The same duplication pattern was observed in 30% of the nuclei obtained from a buccal smear. Methylation studies using polymerase chain reaction with sodium bisulfite-treated DNA demonstrated a normal biparental methylation pattern. To the best of our knowledge, this is the first case with AS and a FISH detectable deletion in a mosaic pattern. We recommend FISH studies for the detection of mosaicism in the patients with AS clinical findings even if results of the methylation studies are normal.

Analysis of variability of clinical manifestations in Waardenburg syndrome.

Expression of clinical findings of Waardenburg syndrome type 1 (WS1) and type 2 (WS2) is extremely variable. Using our collection of 26 WS1 and 8 WS2 families, we analyzed the occurrence, severity, and symmetry of clinical manifestations associated with WS. We found significant differences between WS1 and WS2 in deafness, and in pigmentary and craniofacial anomalies. Factor analysis was used to identify manifestations which covaried, resulting in 2 orthogonal factors. Since mean factor scores were found to differ when compared between WS1 and WS2, we suggest that these factors could be useful in distinguishing WS types. We found that the WS gene was transmitted from mothers more often than from fathers. We also extensively examined the W-Index, a continuous measure of dystopia canthorum. Our data suggest that use of the W-Index to discriminate between affected WS1 and WS2 individuals may be problematic since 1) ranges of W-Index scores of affected and unaffected individuals overlapped considerably within both WS1 and WS2, and 2) a considerable number of both affected and unaffected WS2 individuals exhibited W-index scores consistent with dystopia canthorum. Misclassification of families may have implications for risk assessment of deafness, since WS2 families have been reported to have greater incidence of deafness, as confirmed in our study.

Atelosteogenesis type III: a distinct skeletal dysplasia with features overlapping atelosteogenesis and oto-palato-digital syndrome type II.

We present 5 cases of a short-limb dwarfism syndrome whose manifestations overlap those of atelosteogenesis and oto-palato-digital syndrome Type II. Clinical, radiographic, genetic, and histologic data are presented which demonstrate differences between our patients and previously reported cases of these other conditions. We conclude that the disorder seen in these children represents a distinct chondrodysplasia for which we propose the name atelosteogenesis Type III.