Genetic testing in children: ethical and social points to consider.
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Child↗
Biomedical subjects
J W Hanson
Publications and source records attributed to J W Hanson.
Shprintzen-Goldberg syndrome: a clinical analysis.
Shprintzen-Goldberg syndrome is one of a group of disorders characterized by craniosynostosis and marfanoid habitus. Eleven cases were reported previously. We present 4 new patients and review one of the patients of the original report of Shprintzen and Goldberg [1982: J Craniofac Genet Dev Biol 2:65-74], 15 years later. The clinical and radiologic findings on our patients are compared with those of the previously reported patients and also with those of Furlong et al. [1987: Am J Med Genet 26:599-604] and Lacombe and Battin [1993: Clin Dysmorphol 2: 220-224], who share many of the characteristics of Shprintzen-Goldberg syndrome. Some of the clinical data are helpful in determining if the patients of Furlong et al. [1987: Am J Med Genet 26:599-604] and Lacombe and Battin [1993: Clin Dysmorphol 2: 220-224] have a separate syndrome or represent a variant of Shprintzen-Goldberg syndrome. However, radiologic investigations appear to be more specific, since an abnormality of the first and second cervical vertebrae, hydrocephalus, dilatation of the lateral ventricles, and a Chiari-I malformation of the brain were found only in the patients with Shprintzen-Goldberg syndrome. The apparently diagnostic findings of the 15 patients with this syndrome may be helpful in differentiating between Shprintzen-Goldberg syndrome and other syndromes with craniosynostosis and marfanoid habitus.
Abnormalities, Multiple↗
The effect of follow-up on limiting non-participation bias in genetic epidemiologic investigations.
The use of a comprehensive follow-up strategy to limit non-participation bias was evaluated in a population-based case-control study of orofacial clefts. Birth parents were requested to provide exposure data, and index children and parents were asked to provide blood specimens. Follow-up included telephone or postal reminders every two weeks for up to three months. Consent to participate was received from 281 (76.6%) case mothers and 246 (72.4%) case fathers. The corresponding totals for controls were 279 (54.7%) and 245 (49.8%). Evaluation of participation rates by intensity of follow-up showed that 23% of case and 18% of control families consented without reminders (first stage); 81% of cases and 83% of controls agreed following one or two reminders (second stage); and the remainder of participants consented following three or more reminders (final stage). Cumulative distributions of sociodemographic characteristics differed little between second and final stage participants. Odds ratios for maternal multivitamin use were similar between second and final stage participants, whereas those for maternal and paternal smoking tended to decline. Although follow-up measures were necessary to enroll most families, use of more than two reminders did not appear to increase the representativeness of the sample; however, termination of recruitment after only two reminders would have led to different conclusions. Future studies require data collection protocols that encourage participation from all population subgroups, and one alternative is presented.
Adult↗
Incidence of fetal alcohol syndrome and prevalence of alcohol-related neurodevelopmental disorder.
We critique published incidences for fetal alcohol syndrome (FAS) and present new estimates of the incidence of FAS and the prevalence of alcohol-related neurodevelopmental disorder (ARND). We first review criteria necessary for valid estimation of FAS incidence. Estimates for three population-based studies that best meet these criteria are reported with adjustment for underascertainment of highly exposed cases. As a result, in 1975 in Seattle, the incidence of FAS can be estimated as at least 2.8/1000 live births, and for 1979-81 in Cleveland, approximately 4.6/1,000. In Roubaix, France (for data covering periods from 1977-1990), the rate is between 1.3 and 4.8/1,000, depending on the severity of effects used as diagnostic criteria. Utilizing the longitudinal neurobehavioral database of the Seattle study, we propose an operationalization of the Institute of Medicine's recent definition of ARND and estimate its prevalence in Seattle for the period 1975-1981. The combined rate of FAS and ARND is thus estimated to be at least 9.1/1,000. This conservative rate--nearly one in every 100 live births--confirms the perception of many health professionals that fetal alcohol exposure is a serious problem.
Female↗
Magnetic resonance imaging of brain anomalies in fetal alcohol syndrome.
OBJECTIVE: Postmortem studies of fetuses, infants, and young children with fetal alcohol syndrome (FAS) have demonstrated a variety of severe central nervous system (CNS) anomalies. We undertook this magnetic resonance study (1) to assess the spectrum of CNS anomalies that occur in a clinical sample of typical patients with FAS who are medically stable; and (2) to examine the relationship between CNS and facial anomalies. METHODOLOGY: Magnetic resonance imaging was performed on a series of 10 patients (4 children, 3 adolescents, and 3 adults) who met criteria for FAS. We systematically evaluated each scan for brain anomalies and compared total brain tissue volume with that of healthy child, adolescent, and adult control subjects. RESULTS: Six patients had some type of midline anomaly, ranging from partial to complete callosal agenesis (three patients) to hypoplastic corpus callosum (one patient), cavum septi pellucidi (three patients), and cavum vergae (two patients). These midline anomalies were associated with a greater number of facial anomalies. Other brain anomalies identified included micrencephaly, ventriculomegaly, and hypoplasia of the inferior olivary eminences. CONCLUSION: Patients with classic FAS have a high incidence of midline brain anomalies. This finding is consistent with the concept that the midline CNS is a developmental field that is particularly susceptible to the teratogenic effects of alcohol. Furthermore, patients with more severe facial dysmorphologic characteristics are more likely to have midline brain anomalies. In addition, we observed a high incidence of micrencephaly with a wide range of severity.
Adolescent↗
A teratologist to extinction. Ad Hoc Committee on Grant Funding.
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Congenital Abnormalities↗
Web neck anomaly and its association with congenital heart disease.
To investigate the relationship between congenital heart disease and jugular lymphatic obstruction as manifested in web neck anomaly, we used the Iowa Birth Defects Registry to determine the incidence of congenital heart defects (CHD) in infants with and without web neck. Sixty percent of infants with web neck had CHD, with a high incidence of flow-related defects such as hypoplastic left heart, coarctation, and secundum atrial septal defect. Sixty-eight percent of infants with web neck had a genetic syndrome (37% Down syndrome, 13% Ullrich-Turner syndrome, and 5% Noonan syndrome), and 24% had dysmorphic features consistent with lymphatic obstruction sequence. When infants with Down, Ullrich-Turner, and Noonan syndrome and web neck were compared to infants with the same syndrome but without web neck, those with web neck were significantly more likely to have flow-related heart defects. Infants with Ullrich-Turner syndrome and web neck had an 11-fold higher incidence of coarctation, compared to those with a normal neck. Our data suggests web neck is associated with both flow and nonflow-related heart defects. This association implies a pathogenetic relationship and appears to be independent of causal factors. The finding of web neck or nuchal cystic hygroma on a prenatal ultrasound or newborn examination should prompt a search for CHD.
Down Syndrome↗
Summary of workshop: early discharge and neonatal hyperbilirubinemia.
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Humans↗
Postintubation tracheal stenosis: diagnosis and management.
Postintubation damage is a potential hazard in any patient intubated with an oral or nasal endotracheal tube or with a tracheostomy tube for ventilatory support. Postintubation tracheal stenosis may be fatal unless it is recognized and treated promptly. This paper reviews the important features of diagnosis and treatment of postintubation tracheal stenosis.
Adult↗
The association of waterborne chloroform with intrauterine growth retardation.
The potential reproductive effects of long-term, low-dose exposure to chloroform have received little attention despite the known, acute toxicity of high exposures and the wide-spread occurrence of low concentrations in drinking water. We studied the association of waterborne chloroform with low birthweight (less than 2,500 gm), prematurity (less than 37 weeks gestation), and intrauterine growth retardation (less than 5th percentile of weight for gestational age). Cases were not mutually exclusive, but each outcome was analyzed independently. Birth certificates from January 1, 1989, to June 30, 1990, were used to identify cases and randomly selected controls. All were live, singleton infants born to non-Hispanic, white women from Iowa towns with 1,000-5,000 inhabitants. Exposures to chloroform and other trihalomethanes were ecologic variables based on maternal residence and a 1987 municipal water survey. After adjustment for maternal age, parity, adequacy of prenatal care, marital status, education, and maternal smoking by multiple logistic regression, residence in municipalities where chloroform concentrations were greater than or equal to 10 micrograms/liter was associated with an increased risk for intrauterine growth retardation (odds ratio = 1.8, 95% confidence interval = 1.1-2.9). The major limitations of this study involve the ascertainment and classification of exposures to trihalomethanes, including such issues as the imprecision of using aggregate municipal measures for classifying exposure at the level of the individual, the potential misclassification due to residential mobility, and the fluctuation of trihalomethane levels.
Adult↗
Craniofacial development in myotonic dystrophy.
Anthropometric, cephalometric, and dental data from 23 subjects (12 males and 11 females) afflicted with myotonic dystrophy were compared to similar data from normal subjects who participated in the Iowa Facial Growth Study. A two by two analysis of variance showed that myotonic subjects differed from normal subjects in headlength, head breadth, cephalic index, bizygomatic face width, nosebreadth, maxillary arch widths, palatal depth, anterior and posterior face heights, cranial base lengths, cranial base angles, and other cephalometric measures. Sex differences were observed for many of the variables. It is hoped that these findings will assist clinicians who treat patients having this disorder.
Adolescent↗
Unique phenotype associated with a pericentric inversion of chromosome 6 in three generations.
We observed a pericentric inversion of chromosome 6 in three generations of one family. Carriers had several phenotypic alterations including congenital cataracts, hearing loss, dental anomalies, ear anomalies, premature graying, unilateral strabismus, coloboma, and mild mental retardation. These manifestations may all be explained by a failure or delay in development of tissues derived from neural crest cells and are similar to these seen in the Rieger syndrome. The description of this family extends the known phenotypic abnormalities associated with alterations of chromosome 6.
Abnormalities, Multiple↗
A five-year statewide experience with congenital diaphragmatic hernia.
Antenatal in utero surgery for congenital diaphragmatic hernia has been justified by reported perinatal mortality rates of 77% to 80%. Such rates may have been subject to bias of ascertainment and may include fetuses with additional severe malformations who would not be surgical candidates. We used the Iowa Birth Defects Registry to conduct a complete population survey to determine the incidence of congenital diaphragmatic hernia, the frequency of associated severe malformations, and the morbidity and mortality of infants with isolated congenital diaphragmatic hernia who were not subjected to antenatal surgery. The incidence of congenital diaphragmatic hernia was 1 in 3715. Twenty-eight percent of affected fetuses had associated severe malformations that were potentially identifiable prenatally and that would have precluded antenatal surgery. Of those with isolated congenital diaphragmatic hernia, 55% survived in spite of delivery (88.5%) and/or surgical repair (44%) in a level I or II hospital. Any decision for in utero surgery to repair congenital diaphragmatic hernia must be based on this or similarly obtained information.
Abnormalities, Multiple↗
Clinical management issues in males with sex chromosomal mosaicism and discordant phenotype/sex chromosomal patterns.
The recent availability of Y DNA probes has made it possible to identify two forms of 46,XX male syndrome: Y DNA positive and Y DNA negative. The Y DNA positive male results from a X;Y translocation with a low recurrence risk; the Y DNA negative males are due to a mutation with a high recurrence risk. 46,XX males and mosaic forms are phenotypically indistinguishable. A review of the case histories for 11 individuals indicates that affected males have highly variable genital and nongenital phenotypes. Physical findings may be clearly apparent or nonexistent. With the exception of external genitalia, the basis for this variability is unknown. It may be related to differences in Y chromatin expression as the result of variable inactivation of the X chromosomes, or to the existence of minor deletions or point mutations secondary to an exchange of genetic material. Common and uncommon clinical problems in these individuals require evaluation and follow-up care that is provided through a cooperative, interdisciplinary approach.
Adolescent↗
Genetic counseling.
Achieving the clinical goal of genetic counseling continues to be the proper role of all professionals who deal with disorders and conditions that have a genetic component. That group includes the SLP. One major problem is determining when information can be given generally and when referral to a genetic counselor is needed. Another problem is helping the public accept the idea of genetic counseling as one useful part of the health care system. Of special importance now is the development of new methods for identifying the genetic contribution to diseases and disorders. Careful attention is needed for the effective integration of this new technology into our patterns of health care delivery and public health policy in general.
Adolescent↗
Potential human teratogenicity of frequently prescribed drugs.
Published data regarding the human teratogenic potential of 157 drug components that are frequently prescribed to outpatients in the United States were evaluated according to a protocol developed for TERIS, an automated clinical teratology resource. This protocol stipulates that a bibliographic search be performed on each agent, a brief narrative summary of the available teratologic information prepared, and a risk rating assigned. The ratings are determined by consensus of five clinical teratologists, who independently assess the magnitude of teratogenic risk associated with each agent under usual therapeutic conditions as "none," "minimal," "small," "moderate," "high," and "undetermined." Forty-nine percent of the components of these frequently prescribed drugs had insufficient published information available to assess the risk of human teratogenicity. Of the agents that could be rated, the teratogenic risk in usual therapeutic doses was considered to be minimal or less in 92.5%. Many of these agents have also been assigned Pregnancy Categories by the United States Food and Drug Administration (FDA) according to a system designed to provide therapeutic guidance. There was no more agreement than that expected by chance between TERIS ratings and the FDA Pregnancy Categories for 83 agents that were classified according to both systems. We believe that the FDA Pregnancy Categories should not be used to provide counseling regarding the risk of teratogenic effects to women who have taken medication during pregnancy. Such counseling should be based on a more comprehensive evaluation of the teratologic literature and clinical situation, but need not involve consideration of the therapeutic benefit of the agent.
Information Systems↗
Prenatal cocaine exposure and fetal vascular disruption.
The question of the potential teratogenicity of cocaine has been raised by the increasing frequency of its abuse in the United States. In previous studies, an increased incidence has been documented of spontaneous abortion, placental abruption, prematurity, intrauterine growth retardation, and neurologic deficits in the infants of women who abused cocaine. More recently, it has been suggested in studies that fetal vascular disruption accompanying maternal cocaine abuse may lead to cavitary central nervous system lesions and genitourinary anomalies. In this article, 10 children born of women who abused cocaine are described, 9 of whom have congenital limb reduction defects and/or intestinal atresia or infarction. The spectrum of anomalies associated with embryonic and fetal vascular disruption accompanying maternal cocaine abuse is thus enlarged. The specific risk for congenital anomalies accompanying maternal cocaine abuse during an individual pregnancy is unknown. However, data from these patients and the available literature suggest that counseling pregnant women concerning cocaine use should incorporate warnings about the possibility of associated embryonic or fetal vascular disruption.
Abnormalities, Drug-Induced↗
Criteria for identifying and listing substances known to cause developmental toxicity under California's Proposition 65.
Because of the automatic restrictions and warning requirements imposed on substances identified by the state as "known to cause developmental toxicity," the Expert Committee recommends the use of criteria that emphasize human relevancy, biological plausibility, and evidence in support of a selective, adverse developmental effect at non-maternally-toxic doses. In many instances, data for substances of public concern will be insufficient at present to meet these criteria. The fact that a substance is not listed as "known to cause developmental toxicity" does not create a presumption that the substance is safe. The Expert Committee, therefore, urges that these substances be recommended for further testing and that high priority be given to conducting the necessary tests. The Expert Committee reiterates its concern that substances listed by the SAP be identified according to the toxic endpoints (cancer, male reproductive toxicity, female reproductive toxicity, and/or developmental toxicity) that led to listing. Further, the Expert Committee recommends that the state Health and Welfare Agency institute education programs emphasizing appropriate courses of action for citizens informed of exposures to substances known to the state to cause cancer, birth defects, or reproductive toxicity.
Animals↗