A rational approach to the child with mental retardation for the paediatrician

Correlation between large rearrangements and patient phenotypes in NF1 deletion syndrome: an update and review

About 5-10% of neurofibromatosis type 1 (NF1) patients exhibit large genomic germline deletions that remove the NF1 gene and its flanking regions. The most frequent NF1 large deletion is 1.4 Mb, resulting from homologous recombination between two low copy repeats. This "type-1" deletion is associated with a severe clinical phenotype in NF1 patients, with several phenotypic manifestations including learning disability, a much earlier development of cutaneous neurofibromas, an increased tumour risk, and cardiovascular malformations. NF1 adjacent co-deleted genes could act as modifier loci for the specific clinical manifestations observed in deleted NF1 patients. Furthermore, other genetic modifiers (such as CNVs) not located at the NF1 locus could also modulate the phenotype observed in patients with large deletions. In this study, we analysed 22 NF1 deletion patients by genome-wide array-CGH with the aim (1) to correlate deletion length to observed phenotypic features and their severity in NF1 deletion syndrome, and (2) to identify whether the deletion phenotype could also be modulated by copy number variations elsewhere in the genome. We then review the role of co-deleted genes in the 1.4 Mb interval of type-1 deletions, and their possible implication in the main clinical features observed in this high-risk group of NF1 patients.

An ethical analysis of divergent clinical approaches to the application of genetic testing for autism and schizophrenia

Genetic testing to identify genetic syndromes and copy number variants (CNVs) via whole genome platforms such as chromosome microarray (CMA) or exome sequencing (ES) is routinely performed clinically, and is considered by a variety of organizations and societies to be a "first-tier" test for individuals with developmental delay (DD), intellectual disability (ID), or autism spectrum disorder (ASD). However, in the context of schizophrenia, though CNVs can have a large effect on risk, genetic testing is not typically a part of routine clinical care, and no clinical practice guidelines recommend testing. This raises the question of whether CNV testing should be similarly performed for individuals with schizophrenia. Here we consider this proposition in light of the history of genetic testing for ID/DD and ASD, and through the application of an ethical analysis designed to enable robust, accountable and justifiable decision-making. Using a systematic framework and application of relevant bioethical principles (beneficence, non-maleficence, autonomy, and justice), our examination highlights that while CNV testing for the indication of ID has considerable benefits, there is currently insufficient evidence to suggest that overall, the potential harms are outweighed by the potential benefits of CNV testing for the sole indications of schizophrenia or ASD. However, although the application of CNV tests for children with ASD or schizophrenia without ID/DD is, strictly speaking, off-label use, there may be clinical utility and benefits substantive enough to outweigh the harms. Research is needed to clarify the harms and benefits of testing in pediatric and adult contexts. Given that genetic counseling has demonstrated benefits for schizophrenia, and has the potential to mitigate many of the potential harms from genetic testing, any decisions to implement genetic testing for schizophrenia should involve high-quality evidence-based genetic counseling.

Magnetic Resonance Spectroscopy in Children With Developmental Delay: Time to Look Beyond Conventional Magnetic Resonance Imaging (MRI)

Developmental delay (DD) is an important long-term neuromorbidity owing to various insults to the developing brain and neuroimaging plays a key role in evaluating these children. Magnetic resonance spectroscopy (MRS) is the only noninvasive method to determine the levels of various metabolites in the brain which aids in delineating the underlying abnormalities. A total of 48 children aged between 6 months to 6 years with developmental delay were included and evaluated with neuroimaging in our study. Sensitivity of MRS in children with DD and DD plus (DD along with seizures, abnormal motor findings, behavior, brainstem evoked response audiometry, visual assessment, and microcephaly) was 81.2% and 89.6% respectively. 86.6% of children with microcephaly had abnormal MRS. MRS detected abnormalities in two-thirds of children with normal magnetic resonance imaging (MRI). Children with behavioral abnormalities had significantly lower N-acetyl aspartate (NAA)-creatine and NAA-choline ratios on MRS. Thus, MRS is additive to MRI in delineating the underlying pathophysiology in children with DD.

An open-label proof-of-concept study of intrathecal autologous bone marrow mononuclear cell transplantation in intellectual disability

Background

The underlying pathophysiology in intellectual disability (ID) involves abnormalities in dendritic branching and connectivity of the neuronal network. This limits the ability of the brain to process information. Conceptually, cellular therapy through its neurorestorative and neuroregenerative properties can counteract these pathogenetic mechanisms and improve neuronal connectivity. This improved networking should exhibit as clinical efficacy in patients with ID.

Methods

To assess the safety and efficacy of cellular therapy in patients with ID, we conducted an open-label proof-of-concept study from October 2011 to December 2015. Patients were divided into two groups: intervention group (n = 29) and rehabilitation group (n = 29). The intervention group underwent cellular transplantation consisting of intrathecal administration of autologous bone marrow mononuclear cells and standard neurorehabilitation. The rehabilitation group underwent only standard neurorehabilitation.

The results of the symptomatic outcomes were compared between the two groups. In the intervention group analysis, the outcome measures used were the intelligence quotient (IQ) and the Wee Functional Independence Measure (Wee-FIM). To compare the pre-intervention and post-intervention results, statistical analysis was done using Wilcoxon’s matched-pairs test for Wee-FIM scores and McNemar’s test for symptomatic improvements and IQ. The effect of age and severity of the disorder were assessed for their impact on the outcome of intervention. Positron emission tomography-computed tomography (PET-CT) brain scan was used as a monitoring tool to study effects of the intervention. Adverse events were monitored for the safety of cellular therapy.

Results

On symptomatic analysis, greater improvements were seen in the intervention group as compared to the rehabilitation group. In the intervention group, the symptomatic improvements, IQ and Wee-FIM were statistically significant. A significantly better outcome of the intervention was found in the paediatric age group (<18 years) and patients with milder severity of ID. Repeat PET-CT scan in three patients of the intervention group showed improved metabolism in the frontal, parietal cortex, thalamus, mesial temporal structures and cerebellum. No major adverse events were witnessed.

Conclusions

Cellular transplantation with neurorehabilitation is safe and effective for the treatment of underlying brain deficits in ID.

Trial registration

ClinicalTrials.gov NCT02245724. Registered 12 September 2014.

Concerns for Individuals with Intellectual Disability in India

Intellectual disability (intellectual developmental disorder) is characterized by deficits in general mental abilities, such as reasoning, problem solving, planning, abstract thinking judgment, academic learning, and learning from experience (DSM V). This neuro developmental disorder is one of the conditions with onset in the developmental period. This condition has been classified into four categories on the basis of the individual's IQ (Intelligence quotient). The objective of the present paper is to highlight some of the areas that are related to the concerns for the people with intellectual disability. The paper focuses on the following topics: 1) Legal services, 2) Challenges faced by parents, 3) Health issues, 4) Sexual knowledge, 5) Marriage, 6) Quality of life, 7) Old age, 8) Attitude of society towards the individual with intellectual disability, 9) Implications, management and prevention for future improvement for individuals with intellectual disability.