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For a variety of reasons, the definition and the clawification of cerebral palsy (CP) need to be reconsidered. Modern brain imaging techniques have shed new light on the nature of the underlying brain injury and studies on the neurobiology of and pathology associated with brain development have further explored etiologic mechanisms. It is now recognized that assessing the extent of activity restriction is part of CP evaluation and that people without activity restriction should not be included in the CP rubric. Also, previous definitions have not given sufficient prominence to the non‐motor neurodevelopmental disabilities of performance and behaviour that commonly accompany CP, nor to the progression of musculoskeletal difficulties that often occurs with advancing age. In order to explore this information, pertinent material was reviewed on July 11–13,2004 at an international workshop in Bethesda, MD (USA) organized by an Executive Committee and participated in by selected leaders in the preclinical and clinical sciences. At the workshop, it was agreed that the concept ‘cerebral palsy’ should be retained. Suggestions were made about the content of a revised definition and classification of CP that would meet the needs of clinicians, investigators, health officials, families and the public and would provide a common language for improved communication. Panels organized by the Executive Committee used this information and additional comments from the international community to generate a report on the Definition and Classification of Cerebral Palsy, April 2006. The Executive Committee presents this report with the intent of providing a common conceptualization of CP for use by a broad international audience.

The field of intellectual and developmental disabilities (IDD) is currently experiencing a significant transformation that encompasses an integrated approach, especially regarding shared aspects such as a focus on the human and legal rights, the eligibility for services and supports, and an emphasis on individualized supports provided within inclusive community-based environments. Accompanying this transformation is the increased need of precision in both the operational definitions of IDD-related constructs, and the terminology used to describe the respective construct. the specialized literature was revised, and previous works on the subject by the authors were updated. This article provides psychologists with the current definition of intellectual disability, operational definitions of intellectual disability and developmental disabilities constructs and associated terminology, and the parameters of an integrated approach to disability. Implications for psychologists who are involved in diagnosis, classification, and planning supports for persons with intellectual or developmental disability are discussed.

The increasing survival rates of children who are born very preterm raise issues about the risks of neurological disabilities and cognitive dysfunction. We aimed to investigate neurodevelopmental outcome and use of special health care at 5 years of age in a population-based cohort of very preterm children. We included all 2901 livebirths between 22 and 32 completed weeks of gestation from nine regions in France in Jan 1–Dec 31, 1997, and a reference group of 667 children from the same regions born at 39–40 weeks of gestation. At 5 years of age, children had a medical examination and a cognitive assessment with the Kaufman assessment battery for children (K-ABC), with scores on the mental processing composite (MPC) scale recorded. Data for health-care use were collected from parents. Severe disability was defined as non-ambulatory cerebral palsy, MPC score less than 55, or severe visual or hearing deficiency; moderate deficiency as cerebral palsy walking with aid or MPC score of 55–69; and minor disability as cerebral palsy walking without aid, MPC score of 70–84, or visual deficit (<3/10 for one eye). In total, 1817 (77%) of the 2357 surviving children born very preterm had a medical assessment at 5 years and 396 (60%) of 664 in the reference group. Cerebral palsy was diagnosed in 159 (9%) of children born very preterm. Scores for MPC were available for 1534 children born very preterm: 503 (32%) had an MPC score less than 85 and 182 (12%) had an MPC score less than 70. Of the 320 children in the reference group, the corresponding values were 37 (12%) and 11 (3%), respectively. In the very preterm group, 83 (5%) had severe disability, 155 (9%) moderate disability, and 398 (25%) minor disability. Disability was highest in children born at 24–28 completed weeks of gestation (195 children [49%]), but the absolute number of children with disabilities was higher for children born at 29–32 weeks (441 children [36%]). Special health-care resources were used by 188 (42%) of children born at 24–28 weeks and 424 (31%) born at 29–32 weeks, compared with only 63 (16%) of those born at 39–40 weeks. In children who are born very preterm, cognitive and neuromotor impairments at 5 years of age increase with decreasing gestational age. Many of these children need a high level of specialised care. Prevention of the learning disabilities associated with cognitive deficiencies in this group is an important goal for modern perinatal care for children who are born very preterm and for their families.

Matthew Hurles, David FitzPatrick and colleagues report the discovery of four novel Mendelian disorders based on their analysis of exome sequence data from 4,125 families with diverse rare developmental disorders. They present their analytical pipeline as a general strategy for the discovery of genetic causes of autosomal recessive disorders. Discovery of most autosomal recessive disease-associated genes has involved analysis of large, often consanguineous multiplex families or small cohorts of unrelated individuals with a well-defined clinical condition. Discovery of new dominant causes of rare, genetically heterogeneous developmental disorders has been revolutionized by exome analysis of large cohorts of phenotypically diverse parent-offspring trios 1 , 2 . Here we analyzed 4,125 families with diverse, rare and genetically heterogeneous developmental disorders and identified four new autosomal recessive disorders. These four disorders were identified by integrating Mendelian filtering (selecting probands with rare, biallelic and putatively damaging variants in the same gene) with statistical assessments of (i) the likelihood of sampling the observed genotypes from the general population and (ii) the phenotypic similarity of patients with recessive variants in the same candidate gene. This new paradigm promises to catalyze the discovery of novel recessive disorders, especially those with less consistent or nonspecific clinical presentations and those caused predominantly by compound heterozygous genotypes.

Chromosome 16 is one of the most gene-rich chromosomes of our genome, and 10% of its sequence consists of segmental duplications, which give instability and predisposition to rearrangement by the recurrent mechanism of non-allelic homologous recombination. Microarray technologies have allowed for the analysis of copy number variations (CNVs) that can contribute to the risk of developing complex diseases. By array comparative genomic hybridization (CGH) screening of 1476 patients, we detected 27 cases with CNVs on chromosome 16. We identified four smallest regions of overlapping (SROs): one at 16p13.11 was found in seven patients; one at 16p12.2 was found in four patients; two close SROs at 16p11.2 were found in twelve patients; finally, six patients were found with atypical rearrangements. Although phenotypic variability was observed, we identified a male bias for Childhood Apraxia of Speech associated to 16p11.2 microdeletions. We also reported an elevated frequency of second-site genomic alterations, supporting the model of the second hit to explain the clinical variability associated with CNV syndromes. Our goal was to contribute to the building of a chromosome 16 disease-map based on disease susceptibility regions. The role of the CNVs of chromosome 16 was increasingly made clear in the determination of developmental delay. We also found that in some cases a second-site CNV could explain the phenotypic heterogeneity by a simple additive effect or a pejorative synergistic effect.

Neurodevelopmental disorders such as intellectual disability, autism spectrum disorder and schizophrenia lack precise boundaries in their clinical definitions, epidemiology, genetics and protein–protein interactomes. This calls into question the appropriateness of current categorical disease concepts. Recently, there has been a rising tide to reformulate neurodevelopmental nosological entities from biology upward. To facilitate this developing trend, we propose that identification of unique proteomic signatures that can be strongly associated with patient’s risk alleles and proteome-interactome-guided exploration of patient genomes could define biological mechanisms necessary to reformulate disorder definitions.

Neurodegeneration with brain iron accumulation (NBIA) comprises a heterogeneous group of progressive complex motor disorders characterized by the presence of high brain iron, particularly within the basal ganglia. A number of autosomal recessive NBIA syndromes can present in childhood, most commonly pantothenate kinase‐associated neurodegeneration (PKAN; due to mutations in the PANK2 gene) and phospholipase A2 group 6‐associated neurodegeneration (PLAN; associated with genetic defects in PLA2G6). Mutations in the genes that cause these two neuroaxonal dystrophies are thought to disrupt the normal cellular functions of phospholipid remodelling and fatty acid metabolism. A significant proportion of children with an NBIA phenotype have no genetic diagnosis and there are, no doubt, additional as yet undiscovered genes that account for a number of these cases. NBIA disorders can be diagnostically challenging as there is often phenotypic overlap between the different disease entities. This review aims to define the clinical, radiological, and genetic features of such disorders, providing the clinician with a stepwise approach to appropriate neurological and genetic investigation, as well as a clinical management strategy for these neurodegenerative syndromes.

Background Cohen Syndrome (COH1) is a rare autosomal recessive disorder, principally identified by ocular, neural and muscular deficits. We identified three large consanguineous Pakistani families with intellectual disability and in some cases with autistic traits. Methods Clinical assessments were performed in order to allow comparison of clinical features with other VPS13B mutations. Homozygosity mapping followed by whole exome sequencing and Sanger sequencing strategies were used to identify disease-related mutations. Results We identified two novel homozygous deletion mutations in VPS13B , firstly a 1 bp deletion, NM_017890.4:c.6879delT; p.Phe2293Leufs*24, and secondly a deletion of exons 37-40, which co-segregate with affected status. In addition to COH1-related traits, autistic features were reported in a number of family members, contrasting with the “friendly” demeanour often associated with COH1. The c.6879delT mutation is present in two families from different regions of the country, but both from the Baloch sub-ethnic group, and with a shared haplotype, indicating a founder effect among the Baloch population. Conclusion We suspect that the c.6879delT mutation may be a common cause of COH1 and similar phenotypes among the Baloch population. Additionally, most of the individuals with the c.6879delT mutation in these two families also present with autistic like traits, and suggests that this variant may lead to a distinct autistic-like COH1 subgroup.

Extremely low birth weight (ELBW) is associated with impaired neurodevelopmental outcome in infancy. Information on the long-term cognitive and neurological consequences of ELBW is scarce. We aimed to identify the perinatal and neonatal factors of ELBW infants associated with adverse cognitive and neurological outcome at school age. A regional cohort of 135 ELBW infants born between 1993 and 1998 was prospectively evaluated at 3, 6, 12, and 18 months postmenstrual age and at yearly intervals up to age 10 years. The comprehensive follow-up programme for high-risk infants included neurological examinations and psychometric evaluations. According to the overall results of these tests, children were classified as either being normal or having minor or major impairment. At a mean age of 8.4 (SD: 1.6) years, 43% of children had survived without any impairment. Minor impairment was diagnosed in 39% and major impairment in 18% of assessed children. The proportion of disabled school children rose with decreasing gestational age. The following neonatal complications were significant risk factors for developing major or minor impairment at school age: an increase in head circumference <6 mm per week (OR 4.0, 95% CI: 1.1–14.8), parenteral nutrition ≥6 weeks (OR 2.5, 95% CI: 1.1–6.0), and mechanical ventilation >14 days (OR 2.3, 95% CI: 1.0–5.1). High-grade intraventricular haemorrhage (IVH) and/or PVL (OR 13.3, 95% CI: 4.0–44.9), neonatal seizures (OR 5.2, 95% CI: 1.2–22.4) and bowel perforation, and/or necrotizing enterocolitis (OR 4.4, 95% CI: 1.1–17.0) were significant risk factors for developing major impairment. In spite of the relatively large proportion of normal children, ELBW remains an important risk factor for neurodevelopmental impairment at school age. Thus, measures to prevent complications such as necrotizing enterocolitis, cerebral haemorrhage, and undernutrition remain important goals for neonatal intensive care.

Editorial of vol 31(3).