Newborn screening for adrenoleukodystrophy: implications for therapy

X-Linked adrenoleukodystrophy (X-ALD) is a progressive metabolic condition affecting the adrenal glands and nervous system of males. Although variable in the age of onset and presentation in families, X-ALD does present in characteristic phenotypes including a devastating childhood form that affects 35% of boys with this genetic condition. The majority of males with X-ALD will also develop adrenal insufficiency, which may result in crisis. Early detection is desirable in order to prevent morbidity from this condition. We have recently developed a tandem mass spectroscopy method that allows this to be done during newborn screening for other genetic disorder. In this review, we discuss the rationale for early detection, its effect on treatment, and some of the uncertainties.     

Older women's attitudes towards breast disease,self examination,and screening facilities: implications for communication.

Qualitative research techniques were used in two studies in Edinburgh to explore older women''s attitudes and motivations towards breast disease, self examination, and screening, with a view to identifying appropriate strategies for communication. The results indicated that knowledge of breast disease and screening facilities was poor and that many psychological and emotional issues inhibited self examination. Increasing information about self examination and clinics is unlikely to influence uptake unless it is presented together with emotional support rather than through conventional mass media channels. Such support may best be provided by setting breast screening within general health screening rather than emphasising the single disease.     

Asymptomatic Gaucher disease implications for large-scale screening

Gaucher disease, the most prevalent genetic disorder among Ashkenazi Jews, is characterized by significant phenotypic heterogeneity. Because seven mutations account for more than 96% of the disease alleles in this population, large-scale screening is feasible, and genotyping is commercially available. To date, only 400 Gaucher patients have been diagnosed in Israel, although 2,500 patients are predicted by gene frequency; hence, there is the probability that those uncovered by population screening will prove to be very mild or asymptomatic since these patients have generally escaped medical attention until now. We studied objective and subjective aspects in 68 asymptomatic/very mild patients, followed for a mean of 2.6 years, to assess the implications of identifying many more such patients if large-scale screening were to be implemented. We found there were no medically significant changes in disease severity during follow-up. The patients' subjective reports of their general health status were similar to those of normal subjects, and there were no significant changes in quality of life during follow-up. Our findings suggest that asymptomatic/mild Gaucher patients do not require frequent monitoring; there is no justification for "prophylactic" enzyme therapy in this group, and, hence, no rationale for large-scale screening in the Ashkenazi population. Furthermore, one needs to be concerned with the adverse effects of labeling large numbers of asymptomatic individuals as affected because of the potential for stigmatization and discrimination.     

Cytokines, macrophage lipid metabolism and foam cells: implications for cardiovascular disease therapy

Cardiovascular disease is the biggest killer globally and the principal contributing factor to the pathology is atherosclerosis; a chronic, inflammatory disorder characterized by lipid and cholesterol accumulation and the development of fibrotic plaques within the walls of large and medium arteries. Macrophages are fundamental to the immune response directed to the site of inflammation and their normal, protective function is harnessed, detrimentally, in atherosclerosis. Macrophages contribute to plaque development by internalizing native and modified lipoproteins to convert them into cholesterol-rich foam cells. Foam cells not only help to bridge the innate and adaptive immune response to atherosclerosis but also accumulate to create fatty streaks, which help shape the architecture of advanced plaques. Foam cell formation involves the disruption of normal macrophage cholesterol metabolism, which is governed by a homeostatic mechanism that controls the uptake, intracellular metabolism, and efflux of cholesterol. It has emerged over the last 20 years that an array of cytokines, including interferon-γ, transforming growth factor-β1, interleukin-1β, and interleukin-10, are able to manipulate these processes. Foam cell targeting, anti-inflammatory therapies, such as agonists of nuclear receptors and statins, are known to regulate the actions of pro- and anti-atherogenic cytokines indirectly of their primary pharmacological function. A clear understanding of macrophage foam cell biology will hopefully enable novel foam cell targeting therapies to be developed for use in the clinical intervention of atherosclerosis.     

Protein aggregation in Huntington's and Parkinson's disease: implications for therapy

The accumulation of highly insoluble intracellular protein aggregates in neuronal inclusions is a hallmark of Huntington's disease (HD) and Parkinson's disease (PD) as well as several other late-onset neurodegenerative disorders. The aggregates formed in vitro and in vivo generally have a fibrillar morphology, consist of individual beta-strands and are resistant to proteolytic degradation. Although the causal relationship between aggregate formation and disease remains to be proven, the gradual deposition of mutant protein in neurons is consistent with the late-onset and progressive nature of symptoms. Recently, circumstantial evidence from mouse and Drosophila model systems suggests that abnormal protein folding and aggregation play a key role in the pathogenesis of both HD and PD. Therefore, a detailed understanding of the molecular mechanisms of protein aggregation and its effects on neuronal cell death could open new opportunities for therapy.     

Assessment of care of children with sickle cell disease: implications for neonatal screening programmes.

OBJECTIVE--To assess the quality of care provided by hospitals for young children with sickle cell disease. DESIGN--Retrospective survey. SETTING--Teaching hospital in London. PATIENTS--31 Children (mean age 4 years 4 months, range 4 months to 7 years 5 months) born with sickle cell disease between 1978 and 1985 identified from Hospital Activity Analysis data, an outpatient diagnostic register, and registers of the haematology department. Eight had been diagnosed on neonatal screening and at least four of these had not been followed up. MAIN OUTCOME MEASURES--Aspects of quality of outpatient care (blood testing, clinic attendance, and prophylactic drug treatment) and family care (adequate support and carers'' knowledge about the disease) as assessed by reviewing the notes and administering a semistructured questionnaire to the carers, in relation to a devised list of standards deemed necessary to ensure achievement of the aims of screening. RESULTS--There were 93 outpatient attendances during the previous 12 months, but 13 children had not attended at least every six months and four not at all for more than a year. Only eight children had had three of the blood tests considered to be necessary for good care; three had had none. Prophylactic treatment with penicillin and folic acid was erratic; three children with sickle cell anaemia were not receiving regular prophylactic penicillin. IMPLICATION--Diagnosis of sickle cell disease on neonatal screening must be linked with follow up to ensure optimal management.     

Genetics, statistics and human disease: analytical retooling for complexity

Molecular biologists and geneticists alike now acknowledge that most common human diseases with a genetic component are likely to have complex etiologies. Yet despite this belief, many statistical geneticists continue applying, in slightly new and different ways, methodologies that were developed to dissect much simpler etiologies. In this article, we characterize, with examples, the various factors that can complicate genetic analysis and demonstrate their shared features and how they affect genetic analysis. We describe a variety of approaches that are currently available, revealing methodological gaps and suggesting new directions for method development. Finally, we propose a comprehensive two-step approach to analysis that systemically addresses the different genetic factors that are likely to underlie complex diseases.     

Neurohormonal-cytokine interactions: implications for inflammation, common human diseases and well-being

The neuroendocrine system affects the immune system through the neuroendocrine humoral outflow via the pituitary, and through direct neuronal influences via the sympathetic, parasympathetic (cholinergic) and peptidergic/sensory innervation of peripheral tissues. Circulating hormones or locally released neurotransmitters and neuropeptides regulate major immune functions, such as antigen presentation, antibody production, lymphocyte activity, proliferation and traffic, and the secretion of cytokines including the selection of T helper (Th)1 or Th2 cytokine responses. During inflammation, the activation of the stress system, through induction of a Th2 shift protects the organism from systemic "overshooting" with Th1/pro-inflammatory cytokines. Under certain conditions, however, stress hormones, substance P, ATP and the activation of the corticotropin-releasing hormone/substance P-histamine axis may actually facilitate inflammation, through induction of interleukin (IL)-1, IL-6, IL-8, IL-18, tumor necrosis factor (TNF)-alpha and CRP production. Thus, a dysfunctional neuroendocrine-immune interface associated with abnormalities of the 'systemic anti-inflammatory feedback' and/or 'hyperactivity' of the local pro-inflammatory factors may play a role in the pathogenesis of atopic/allergic and autoimmune diseases, obesity, depression and atherosclerosis. Better understanding of the neuroendocrine control of inflammation may provide critical insights into mechanisms underlying a variety of common human immune-related diseases.     

Hyperphosphatemia in infantile hypophosphatasia: implications for carrier diagnosis and screening.

Twenty obligate carriers of infantile hypophosphatasia (HOPS), a severe autosomal recessive metabolic bone disorder, were studied and compared with 36 controls. Decreased serum alkaline phosphatase activity and increased urinary phosphoethanolamine excretion were confirmed in the HOPS carriers. Relative hyperphosphatemia was documented for the first time in the carriers. Logistic regression analysis was used to develop models for the diagnosis of and screening for HOPS carriers in the high-risk population of Manitoba Mennonites. Models based on serum alkaline phosphatase activity and on serum phosphate levels with or without urinary phosphoethanolamine excretion were used for diagnostic purposes. A model based on serum alkaline phosphatase activity and on the serum phosphate level was the most suitable for screening.     

Genetics, experience, and host-plant preference in Eurosta solidaginis: implications for host shifts and speciation

Host-associated mating is crucial in maintaining the partial reproductive isolation between the host races of Eurosta solidaginis (Diptera: Tephritidae), a fly that forms galls on Solidago altissima and S. gigantea. (We refer to flies reared from S. gigantea as gigantea flies and those reared from S. altissima as altissima flies.) We measured the host preference of males and females of both host races, F1 hybrids between the host races, F2, and backcrosses to both host races. Male and female altissima flies and female gigantea flies had high host fidelity, whereas male gigantea flies had low host fidelity. This result suggests that there may be gene flow between the host races due to nonassortative mating that occurs when male gigantea mate with altissima females on S. altissima. This indicates assortative-mating mechanisms in addition to host-associated mating are required to produce the partial reproductive isolation between the host races that has been observed. Nongenetic factors had no influence on host preference. Larval conditioning did not influence host preference: reciprocal F1 hybrids reared in S. altissima and S. gigantea both preferred S. gigantea. Adult experience had no impact on host preference: females preferred their natal host plant regardless of which host they encountered first as an adult. The hypothesis that maternal effects influence preferences was rejected because male and female flies did not show a consistent preference for the host plant of their mother. We also found no evidence that preference was a sex-linked trait because F1 and backcrosses to the host races with different combinations of X chromosomes from the two host races preferred S. gigantea. Our results indicate that host preference is not determined by a large number of genes because preference of hybrids did not correspond to the proportion of the genome derived from each host race. The strength of the ovipuncture preference for S. gigantea by gigantea females, the females of both reciprocal F1 hybrids, the backcross to gigantea, and F2s indicates that preference is inherited nonadditively at a limited number of loci. The F1 female hybrids, however, had a weaker host preference for S. gigantea than the pure gigantea host race, indicating that there may be incomplete dominance or modifier loci. Males had different host preference patterns than females, with individual male gigantea and male F1 hybrids usually exhibiting preference exclusively for S. gigantea or S. altissima. One hypothesis explaining the difference in host preference between males and females is that the same gene influences both female and male host preference, but it is a sex-influenced gene. Thus, males carrying the gene for S. gigantea preference have an intermediate host preference, whereas females have a strong host preference to S. gigantea. In summary, we found that the host preference that produces host-associated mating is inherited nonadditively at a relatively small number of loci on autosomal genes. This mode of inheritance meets the assumptions of models of sympatric speciation, indicating that the host races could have evolved in sympatry.