A natural history study of X-linked myotubular myopathy.

OBJECTIVE: To define the natural history of X-linked myotubular myopathy (MTM). METHODS: We performed a cross-sectional study that included an online survey (n = 35) and a prospective, 1-year longitudinal investigation using a phone survey (n = 33). RESULTS: We ascertained data from 50 male patients with MTM and performed longitudinal assessments on 33 affected individuals. Consistent with existing knowledge, we found that MTM is a disorder associated with extensive morbidities, including wheelchair (86.7% nonambulant) and ventilator (75% requiring >16 hours of support) dependence. However, unlike previous reports and despite the high burden of disease, mortality was lower than anticipated (approximate rate 10%/y). Seventy-six percent of patients with MTM enrolled (mean age 10 years 11 months) were alive at the end of the study. Nearly all deaths in the study were associated with respiratory failure. In addition, the disease course was more stable than expected, with few adverse events reported during the prospective survey. Few non-muscle-related morbidities were identified, although an unexpectedly high incidence of learning disability (43%) was noted. Conversely, MTM was associated with substantial burdens on patient and caregiver daily living, reflected by missed days of school and lost workdays. CONCLUSIONS: MTM is one of the most severe neuromuscular disorders, with affected individuals requiring extensive mechanical interventions for survival. However, among study participants, the disease course was more stable than predicted, with more individuals surviving infancy and early childhood. These data reflect the disease burden of MTM but offer hope in terms of future therapeutic intervention.

Molecular and clinical analyses with neuropsychological assessment of a case of del(10)(q26.2qter) without intellectual disability: Genomic and transcriptomic combined approach and review of the literature.

Terminal deletion of the long arm of the chromosome 10 is a rare but well known abnormality, with a large phenotypic variability. Very few data are available about subtelomeric deletion 10q26 patients without intellectual disability. Herein, we report the case of a young adult with a classical 10q26.2qter deletion. She exhibited mainly short stature at birth and in childhood/adulthood without intellectual disability or behavioral problems. After clinical and neuropsychological assessments, we performed genomic array and transcriptomic analysis and compared our results to the data available in the literature. The patient presents a 6.525 Mb heterozygous 10q26.2qter deletion, encompassed 48 genes. Among those genes, DOCK1, C10orf90, and CALY previously described as potential candidate genes for intellectual disability, were partially or completed deleted. Interestingly, they were not deregulated as demonstrated by transcriptomic analysis. This allowed us to suggest that the mechanism involved in the deletion 10qter phenotype is much more complex that only the haploinsufficiency of DOCK1 or other genes encompassed in the deletion. Genomic and transcriptomic combined approach has to be considered to understand this pathogenesis. © 2016 Wiley Periodicals, Inc.

Unexplained developmental delay/learning disability: guidelines for best practice protocol for first line assessment and genetic/metabolic/radiological investigations.

BACKGROUND: Investigation of patients, particularly children, with unexplained global developmental delay (GDD)/learning disability (LD) has been challenging due to a lack of clear guidance from specialised centres. Limited knowledge of rare diseases and a poor understanding of the purpose or limitations of appropriate investigations have been some of the principal reasons for this difficulty. AIMS: A guideline development group was formed to recommend on appropriate, first line metabolic, genetic and radiological investigations for children and adults with unexplained GDD/ID. METHODS AND RECOMMENDATIONS: A comprehensive literature search was conducted, evaluated and reviewed by the guideline committee and a best practice protocol for first line assessment and genetic, metabolic and radiological investigations was decided upon after considering diagnostic yield, practicality, treatability and costs. CONCLUSION: It is hoped that these recommendations will become national guidelines for the first line metabolic, genetic and radiological investigation of patients presenting with unexplained GDD/ID.

A scoping study to explore the cost-effectiveness of next-generation sequencing compared with traditional genetic testing for the diagnosis of learning disabilities in children.

BACKGROUND: Learning disability (LD) is a serious and lifelong condition characterised by the impairment of cognitive and adaptive skills. Some cases of LD with unidentified causes may be linked to genetic factors. Next-generation sequencing (NGS) techniques are new approaches to genetic testing that are expected to increase diagnostic yield. OBJECTIVES: This scoping study focused on the diagnosis of LD in children and the objectives were to describe current pathways that involve the use of genetic testing; collect stakeholder views on the changes in service provision that would need to be put in place before NGS could be used in clinical practice; describe the new systems and safeguards that would need to be put in place before NGS could be used in clinical practice; and explore the cost-effectiveness of using NGS compared with conventional genetic testing. METHODS: A research advisory group was established. This group provided ongoing support by e-mail and telephone through the lifetime of the study and also contributed face-to-face through a workshop. A detailed review of published studies and reports was undertaken. In addition, information was collected through 33 semistructured interviews with key stakeholders. RESULTS: NGS techniques consist of targeted gene sequencing, whole-exome sequencing (WES) and whole-genome sequencing (WGS). Targeted gene panels, which are the least complex, are in their infancy in clinical settings. Some interviewees thought that during the next 3-5 years targeted gene panels would be superseded by WES. If NGS technologies were to be fully introduced into clinical practice in the future a number of factors would need to be overcome. The main resource-related issues pertaining to service provision are the need for additional computing capacity, more bioinformaticians, more genetic counsellors and also genetics-related training for the public and a wide range of staff. It is also considered that, as the number of children undergoing genetic testing increases, there will be an increase in demand for information and support for families. The main issues relating to systems and safeguards are giving informed consent, sharing unanticipated findings, developing ethical and other frameworks, equity of access, data protection, data storage and data sharing. There is little published evidence on the cost-effectiveness of NGS technologies. The major barriers to determining cost-effectiveness are the uncertainty around diagnostic yield, the heterogeneity of diagnostic pathways and the lack of information on the impact of a diagnosis on health care, social care, educational support needs and the wider family. Furthermore, as NGS techniques are currently being used only in research, costs and benefits to the NHS are unclear. CONCLUSIONS: NGS technologies are at an early stage of development and it is too soon to say whether they can offer value for money to the NHS as part of the LD diagnostic process. Substantial organisational changes, as well as new systems and safeguards, would be required if NGS technologies were to be introduced into NHS clinical practice. Considerable further research is required to establish whether using NGS technologies to diagnose learning disabilities is clinically effective and cost-effective. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Cost Effectiveness of Using Array-CGH for Diagnosing Learning Disability.

OBJECTIVE: To undertake a cost-effectiveness analysis of using microarray comparative genomic hybridisation (array-CGH) as a first-line test versus as a second-line test for the diagnosis of causal chromosomal abnormalities in patients referred to a NHS clinical genetics service in the U.K. with idiopathic learning disability, developmental delay and/or congenital anomalies. METHODS: A cost-effectiveness study was conducted. The perspective is that of a U.K. NHS clinical genetics service provider (with respect to both costs and outcomes). A cohort of patients (n = 1590) referred for array-CGH testing of undiagnosed learning disability and developmental delay by a single NHS regional clinical genetics service (South East Thames Regional Genetics Service), were split into a before-and-after design where 742 patients had array-CGH as a second-line test (before group-comparator intervention) and 848 patients had array-CGH as a first-line test (after group-evaluated intervention). The mean costs were calculated from the clinical genetics testing pathway constructed for each patient including the costs of genetic testing undertaken and clinical appointments scheduled. The outcome was the number of diagnoses each intervention produced so that a mean cost-per-diagnosis could be calculated. The cost effectiveness of the two interventions was calculated as an incremental cost-effectiveness ratio to produce an incremental cost-per-diagnosis (in 2013 GBP). Sensitivity analyses were conducted by altering both costs and effects to check the validity of the outcome. RESULTS: The incremental mean cost of testing patients using the first-line testing strategy was -GBP241.56 (95% CIs -GBP256.93 to -GBP226.19) and the incremental mean gain in the percentage diagnoses was 0.39% (95% CIs -2.73 to 3.51%), which equates to an additional 1 diagnosis per 256 patients tested. This cost-effectiveness study comparing these two strategies estimates that array-CGH first-line testing dominates second-line testing because it was both less costly and as effective. The sensitivity analyses conducted (adjusting both costs and effects) supported the dominance of the first-line testing strategy (i.e. lower cost and as effective). CONCLUSIONS: The first-line testing strategy was estimated to dominate the second-line testing strategy because it was both less costly and as effective. These findings are relevant to the wider UK NHS clinical genetics service, with two key strengths of this study being the appropriateness of the comparator interventions and the direct applicability of the patient cohort within this study and the wider UK patient population.

Use of a medication passport in a disabled child seen across many care settings.

Written information for patients about their medicines has demonstrable benefits for their understanding and adherence. In the UK, no single, complete record of medications for individual patients can be guaranteed. Therefore, patients and carers are often relied on to recall the complete medication list, which can be a challenge given multiple and potentially stressful appointments. Wide-ranging feedback suggests that a medication 'passport' developed by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care North West London (NIHR CLAHRC NWL) has benefited elderly patients, who often attend many appointments where the current medication list may not be available. We describe the use of this passport (known as 'My Medication Passport'--MMP) in a child with multiple disabilities. The practical advantages are explored, including the potential for a paediatric version to facilitate discussions around the administration of medicines. MMP is an early example of a useful tool to help children and young people, parents and carers to manage medicines more effectively.

The role of DCDC2 genetic variants and low socioeconomic status in vulnerability to attention problems.

Both genetic and socio-demographic factors influence the risk for behavioral problems in the developmental age. Genetic studies indicate that shared genetic factors partially contribute to behavioral and learning problems, in particular reading disabilities (RD). For the first time, we explore the conjoint role of DCDC2 gene, an identified RD candidate gene, and socioeconomic status (SES) upon behavioral phenotypes in a general population of Italian children. Two of the most replicated DCDC2 markers [i.e., regulatory element associated with dyslexia 1 (READ1), rs793862] were genotyped in 631 children (boys = 314; girls = 317) aged 11-14 years belonging to a community-based sample. Main and interactive effects were tested by MANOVA for each combination of DCDC2 genotypes and socioeconomic status upon emotional and behavioral phenotypes, assessed by Child Behavior Check-List/6-18. The two-way MANOVA (Bonferroni corrected p value = 0.01) revealed a trend toward significance of READ1(4) effect (F = 2.39; p = 0.016), a significant main effect of SES (F = 3.01; p = 0.003) and interactive effect of READ1(4) × SES (F = 2.65; p = 0.007) upon behavioral measures, showing higher attention problems scores among subjects 'READ1(4+) and low SES' compared to all other groups (p values range 0.00003-0.0004). ANOVAs stratified by gender confirmed main and interactive effects among girls, but not boys. Among children exposed to low socioeconomic level, READ1 genetic variant targets the worst outcome in children's attention.

An assessment of transmission disequilibrium between quantitative measures of childhood problem behaviors and DRD2/Taql and DRD4/48bp-repeat polymorphisms.

In a pilot study of 120 children with reading disabilities, we assessed the presence of linkage and association between the DRD2/Taql and the DRD4/48bp-repeat polymorphisms and quantitative measures of behavioral problems derived from parental rated Child Behavior Checklist (CBCL) [Achenbach, T. M. (1991). TM Manual for the CBCL 14-18. Burlington, VT: University of Vermont]. Analyses included measures of between-family association, and a test of the presence of linkage and association by a logistic regression-based extension of the Transmission Disequilibrium Test (i.e., the logistic regression quantitative TDT). In between-family association analyses the "Social Problem" scale was weakly associated with the number of risk alleles of DRD2 and DRD4, while the "Withdrawn" scale was related to the number of risk alleles of DRD4 (the 7-repeat and the A1 allele respectively were considered the risk alleles). Logistic regression quantitative TDTs yielded statistically significant evidence in favor of linkage and association between DRD2 and "Social Problems" (Wald chi2 = 4.13, df = 1, p = 0.042, odds ratio = 1.97). A statistical trend in favor of linkage and association was found for "Withdrawn" and DRD4 (Wald chi2 = 2.65, df = 1, p = 0.104, odds ratio =1.44). Although preliminary, these findings are consistent with previous data that suggest a role of the same polymorphism in influencing individual sensitivity to reward and response to social cues and reinforcements in man and animal.

Psychometric assessment of first-degree relatives of 62 autistic probands in Utah.

The Wechsler Intelligence Scales, Wide Range Achievement Test, and the Shipley-Hartford Test were administered to 122 parents and 153 siblings of 62 autistic probands in Utah. Scores were distributed as expected within the published normative ranges for each scale. Parents' scores correlated with those of their nonautistic children, but neither parents' nor siblings' scores correlated with the IQ level of the autistic probands. These results do not confirm prior reports from England and the United States of a high rate of cognitive and learning problems in the siblings of autistic individuals, nor the aggregation of such problems in the siblings of probands with high or low levels of cognitive function.

Preschool risk factors as predictors of early school performance.

The relative importance of selected developmental, medical, and social factors in assessing a child's early academic potential was evaluated prospectively in a rural southern school district. Two hundred and ten (210) preschoolers were given the Sprigle School Readiness Screening Test (SSRST) and the Beery Test of Visual Motor Integration (VMI) while physicians rated the children's attention span. A parental questionnaire assessed medical, behavioral, social, and family variables. Follow-up school data were available on 176 children (84%). Using regression techniques, reading and math achievement scores were directly correlated with maternal education, SSRST and VMI results, and lack of family history of learning problems, whereas grade failure was associated with low VMI scores, decreased maternal education, boys with late birthdays, and family history of learning problems. Medical problems and parental preschool behavior concerns were unrelated to school achievement, but physician rating of preschool attention span showed a significant correlation with reading and math scores. A 0-11 Risk Index of School Capability (RISC) scale based on data analyses was developed to rate a preschooler's early academic potential. A score of 7 or above had a 98% positive predictive value of successful grade completion, whereas a score of 3 or below had a 70% predictive value for grade failure. The value of assessing the scores of the VMI and SSRST alone was also considered, but was found less useful. This study demonstrates the importance of evaluating a number of risk factors in assessing a preschooler's early academic potential. Such data can be used to focus school resources for children at increased risk for grade failure.

Assessment of sex differences for multifactorial traits using path analysis: application to learning difficulties.

A general model of multifactorial inheritance is described which allows for sex-specific transmission from parent to offspring, sex-specific correlations in the rearing environments of full siblings, and different prevalences for males and females for qualitative traits. Formulas for the correlations between several types of relatives are given in terms of an underlying path model, and a computer program, available upon request, is described. The model is applied to the Collaborative Perinatal Project sample of siblings and first cousins of children with learning difficulties. No sex differences were found either in transmission or in correlated sibling environments for learning difficulties. Evidence is given that the correlation between the rearing environments of siblings is negative, possibly due to differential allocation and family resources.