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Results for “Neurodevelopmental Disorders”

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PubMed1999

Oral-motor dysfunction in children who fail to thrive: organic or non-organic?

Forty-seven children with non-organic failure to thrive (NOFT) were identified from a whole-population survey of children's growth and development. A significant proportion (N=17) of these 47 children were found to have oral-motor dysfunction (OMD) identified using a previously validated assessment tool. NOFT children with OMD and those with normal oral-motor function (N=30) were compared in order to ascertain whether there were any neurodevelopmental differences which might explain this finding. We hypothesized that children with OMD might have a subtle neurodevelopmental disorder. Few psychosocial variables discriminated the two groups. However, cognitive stimulation within the home and cognitive-growth fostering during mealtimes was much poorer for children with OMD. Some evidence has suggested that NOFT children with OMD may be 'biologically' more vulnerable from birth. We suggest that the continued use of the term 'non-organic' to describe failure to thrive in such children is questionable and requires redefining.

Brain Damage, Chronic↗

PubMed1999

Quality of general movements in infancy is related to neurological dysfunction, ADHD, and aggressive behaviour.

The quality of general movements (GMs) was assessed repeatedly during the first postnatal months in a mixed group of 52 children at either low or high risk for neurodevelopmental disorders. In addition, all children were reexamined at 4 to 9 years. The follow-up assessment consisted of a neurological examination and an evaluation of behaviour by means of parental questionnaires. The quality of GMs changed frequently, to stabilize in the final phase. The final GM phase is that of the so-called fidgety GMs which occurs between 2 and 4 months postterm. The quality of the fidgety GMs predicted outcome very well. Definitely abnormal GMs were associated with a high risk for the development of cerebral palsy, whereas mildly abnormal GMs were associated with the development of minor neurological dysfunction, attention-deficit-hyperactivity disorder, and aggressive behaviour.

Aggression↗

PubMed2005

Brain anatomy in non-affected parents of autistic probands: a MRI study.

BACKGROUND: Autism is a neurodevelopmental disorder with an estimated genetic origin of 90%. Previous studies have reported an increase in brain volume of approximately 5% in autistic subjects, especially in children. If this increase in brain volume is genetically determined, biological parents of autistic probands might be expected to show brain enlargement, or at least intracranial enlargement, as well. Identifying structural brain abnormalities under genetic control is of particular importance as these could represent endophenotypes of autism. METHOD: Using quantitative anatomic brain magnetic resonance imaging, volumes of intracranial, total brain, frontal, parietal, temporal and occipital lobe, cerebral and cortical gray and white matter, cerebellum, lateral ventricle, and third ventricle were measured in biological, non-affected parents of autistic probands (19 couples) and in healthy, closely matched control subjects (20 couples). RESULTS: No significant differences were found between the parents of the autistic probands and healthy control couples in any of the brain volumes. Adding gender as a factor in a second analysis did not reveal a significant interaction effect of gender by group. CONCLUSIONS: The present sample of biological, non-affected parents of autistic probands did not show brain enlargements. As the intracranium is not enlarged, it is unlikely that the brain volumes of the parents of autistic probands have originally been enlarged and have been normalized. Thus, increased brain volume in autism might be caused by the interaction of paternal and maternal genes, possibly with an additional effect of environmental factors, or increased brain volumes might reflect phenotypes of autism.

Autistic Disorder↗

PubMed2006

No evidence for preferential involvement of medial temporal lobe structures in high-functioning autism.

BACKGROUND: Autism is a neurodevelopmental disorder associated with slight increases in brain volume. There has been some suggestion that medial temporal lobe structures may be preferentially involved in this disorder, although results have not always been consistent. Here, we investigate amygdala and hippocampus volumes in medication-naive subjects with high-functioning autism. METHOD: Whole-brain magnetic resonance imaging scans were acquired from 42 patients and 42 closely matched, healthy control subjects. RESULTS: Amygdala volume did not differ significantly between patients and controls. A significant increase in hippocampal volume was proportional to an increase in overall brain volume. CONCLUSIONS: These results argue against preferential involvement of medial temporal lobe structures in autism, at least in high-functioning medication-naive individuals.

Adolescent↗

PubMed1997

Word learning in a special population: do individuals with Williams syndrome obey lexical constraints?

Williams syndrome (WS), a rare neurodevelopmental disorder, is of special interest to developmental psycholinguists because of its uneven linguistico-cognitive profile of abilities and deficits. One proficiency manifest in WS adolescents and adults is an unusually large vocabulary despite serious deficits in other domains. In this paper, rather than focus on vocabulary size, we explore the processes underlying vocabulary acquisition, i.e. how new words are learned. A WS group was compared to groups of normal MA-matched controls in the range 3-9 years in four different experiments testing for constraints on word learning. We show that in construing the meaning of new words, normal children at all ages display fast mapping and abide by the constraints tested: mutual exclusivity, whole object and taxonomic. By contrast, while the WS group showed fast mapping and the mutual exclusivity constraint, they did not abide by the whole object or taxonomic constraints. This suggests that measuring only the size of WS vocabulary can distort conclusions about the normalcy of WS language. Our study shows that despite equivalent behaviour (i.e. vocabulary test age), the processes underlying how vocabulary is acquired in WS follow a somewhat different path from that of normal children and that the atypically developing brain is not necessarily a window on normal development.

Age Factors↗

PubMed2005

Clinical stringency greatly improves mutation detection in Rett syndrome.

BACKGROUND: Rett syndrome (RTT) is a severe neurodevelopmental disorder of girls, caused by mutations in the X-linked MECP2 gene. Worldwide recognition of the RTT clinical phenotype in the early 1980's allowed many cases to be diagnosed, and established RTT as one of the most common mental retardation syndromes in females. The years since then led to a refinement of the phenotype and the recent elaboration of Revised Diagnostic Criteria (RDC). Here, we study the impact of the presence versus the absence of the use of diagnostic criteria from the RDC to make a diagnosis of RTT on MECP2 mutation detection in Canadian patients diagnosed and suspected of having RTT. METHODS: Using dHPLC followed by sequencing in all exons of the MECP2 gene, we compared mutation detection in a historic cohort of 35 patients diagnosed with RTT without the use of specific diagnostic criteria to a separate more recent group of 101 patients included on the basis of strict fulfillment of the RDC. RESULTS: The MECP2 mutation detection rate was much higher in subjects diagnosed using a strict adherence to the RDC (20% vs. 72%). CONCLUSIONS: These results suggest that clinical diagnostic procedures significantly influence the rate of mutation detection in RTT, and more generally emphasize the importance of diagnostic tools in the assessment of neurobehavioral syndromes.

Behavior↗

PubMed2000

Male prevalence for reading disability is found in a large sample of black and white children free from ascertainment bias.

Male vulnerability to neurodevelopmental disorders remains controversial. For one disorder, reading disability, this sex bias has been interpreted as an artifact of referral bias. We investigated sex differences for the incidence of reading disability within a large prospective sample of White (N = 16,910) and Black (N = 15,313) children derived from the National Collaborative Perinatal Project (NCPP). Children were classified as having either moderate or severe reading disability when they had reading scores lower than 1.5 or 2.0 standard errors of prediction, respectively, given their age and intelligence. Reading disability was about twice as common in boys than girls (p < .001), irrespective of race, severity of disability, or exclusion of children with attentional disturbances or high activity levels. We conclude that there is a clear sex bias toward males for the incidence of reading disabilities.

Black or African American↗

PubMed2005

Prader-Willi syndrome: clinical genetics, cytogenetics and molecular biology.

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder that arises from lack of expression of paternally inherited genes known to be imprinted and located in the chromosome 15q11-q13 region. PWS is considered the most common syndromal cause of life-threatening obesity and is estimated at 1 in 10,000 to 20,000 individuals. A de novo paternally derived chromosome 15q11-q13 deletion is the cause of PWS in about 70% of cases, and maternal disomy 15 accounts for about 25% of cases. The remaining cases of PWS result either from genomic imprinting defects (microdeletions or epimutations) of the imprinting centre in the 15q11-q13 region or from chromosome 15 translocations. Here, we describe the clinical presentation of PWS, review the current understanding of causative cytogenetic and molecular genetic mechanisms, and discuss future directions for research.

Chromosome Aberrations↗

PubMed2000

Effects of Rett syndrome mutations of the methyl-CpG binding domain of the transcriptional repressor MeCP2 on selectivity for association with methylated DNA.

We have investigated the properties of mutant forms of the methyl-CpG binding transcriptional repressor MeCP2 associated with Rett syndrome, a childhood neurodevelopmental disorder. We find that four Rett syndrome mutations at known sites within the methyl-CpG binding domain (MBD) impair binding to methylated DNA, but have little effect on nonspecific interactions with unmethylated DNA. Three of these mutations (R106W, R133C, and F155S) have their binding affinities for methylated DNA reduced more than 100-fold; this is consistent with the hypothesis that impaired selectivity for methylated DNA of mutant MeCP2 contributes to Rett syndrome. However, a fourth mutant, T158M, has its binding affinity for methylated DNA reduced only 2-fold, indicative either of additional distinct regulatory functions associated with the MBD or of an exquisite sensitivity of developing neurons to the selective association of MeCP2 with methylated DNA.

Amino Acid Sequence↗

PubMed2001

Dysregulation of Reelin and Bcl-2 proteins in autistic cerebellum.

Autism is a severe neurodevelopmental disorder with potential genetic and environmental causes. Cerebellar pathology including Purkinje cell atrophy has been demonstrated previously. We hypothesized that cell migration and apoptotic mechanisms may account for observed Purkinje cell abnormalities. Reelin is an important secretory glycoprotein responsible for normal layering of the brain. Bcl-2 is a regulatory protein responsible for control of programmed cell death in the brain. Autistic and normal control cerebellar corteces matched for age, sex, and post-mortem interval (PMI) were prepared for SDS-gel electrophoresis and Western blotting using specific anti-Reelin and anti-Bcl-2 antibodies. Quantification of Reelin bands showed 43%, 44%, and 44% reductions in autistic cerebellum (mean optical density +/- SD per 30 microg protein 4.05 +/- 4.0, 1.98 +/- 2.0, 13.88 +/- 11.9 for 410 kDa, 330 kDa, and 180 kDa bands, respectively; N = 5) compared with controls (mean optical density +/- SD per 30 microg protein, 7.1 +/- 1.6, 3.5 +/- 1.0, 24.7 +/- 5.0; N = 8, p < 0.0402 for 180 kDa band). Quantification of Bcl-2 levels showed a 34% to 51% reduction in autistic cerebellum (M +/- SD per 75 microg protein 0.29 +/- 0.08; N = 5) compared with controls (M +/- SD per 75 microg protein 0.59 +/- 0.31; N = 8, p < 0.0451). Measurement of beta-actin (M +/- SD for controls 7.3 +/- 2.9; for autistics 6.77 +/- 0.66) in the same homogenates did not differ significantly between groups. These results demonstrate for the first time that dysregulation of Reelin and Bcl-2 may be responsible for some of the brain structural and behavioral abnormalities observed in autism.

Adult↗

PubMed2001

Proteomic approach for the elucidation of biological defects in autism.

Proteomic-based approaches, which examine expressed proteins in tissues or cells, have great potential in the elucidation of biological defects in heterogeneous neurodevelopmental disorders such as autism. In this approach, tissue or cellular proteins from control and affected subjects are separated on two-dimensional (2-D) polyacrylamide gel electrophoresis, and those proteins that show marked changes in the concentration between control and affected subjects are identified by mass spectroscopy. This method has been successfully applied in the elucidation of the molecular biological defect in classic late-infantile neuronal ceroid lipofuscinosis (Sleat et al., 1997). Unlike the classical methods of genome-wide screening for chromosomal localization followed by positional cloning, the proteomic approach requires limited number of tissue samples and the study can be completed in a relatively short time. Currently, these methods are available for relatively abundant proteins and generally are not applicable for hydrophobic proteins because 2-D gel electrophoresis is not very effective in the analysis of hydrophobic proteins. The genetic defect results in either total loss of proteins or changes in molecular weight and/or isoelectric point will be detectable by the proteomic method. Because autism is a neurogenetic disorder, brain is the tissue of choice for proteomic study. For an oligogenic disorder such as autism, at least some of the aberrant (genes) proteins may be identified by this technology.

Autistic Disorder↗

PubMed2003

Brief report: A case of autism associated with del(2)(q32.1q32.2) or (q32.2q32.3).

Autism is a neurodevelopmental disorder presenting in the first 3 years of life. Deficits occur in the three core areas of communication, social interaction, and behavior. The causes of autism are unknown, but clinical genetic studies show strong evidence in favor of a genetic etiology. Molecular genetic studies report some association with candidate genes, and candidate regions have emerged from several genome-wide linkage studies. Here we report a clinical case of autism with a deletion on chromosome 2 in a young male with high-functioning autism. The deletion seems to correspond with regions emerging from linkage studies. We propose this as a possible candidate region in the search for autism genes.

Adolescent↗

PubMed1997

Catatonia in an adolescent with Prader-Willi Syndrome.

Catatonia in children and adolescents has received little research attention. Treatment and course of catatonia in an adolescent patient with Prader-Willi Syndrome are presented. Clinical features of a small series of published case reports of catatonia in children and adolescents are reported. The association between catatonia, Prader-Willi Syndrome, and other neurodevelopmental disorders is discussed.

Adolescent↗

PubMed2000

[Alcohol and pregnancy--embryopathy and alcohol effects].

Fetal alcohol syndrome (FAS) is a specific polydystrophic pattern of malformations with the following diagnostic criteria: 1. Maternal alcohol dependence or alcohol abuse during pregnancy. 2. Pre- and postnatal deficiency of growth in weight, height and head circumference. 3. Multiple minor and major anomalies recognizable mainly at a typical face. 4. Structural injuries and changes at the central nervous system with complex brain dysfunction combining elements of cognitive impairments, behavioral disturbance and neurological damage. Fetal alcohol effects (FAE) or so-called "alcohol-related neurodevelopmental disorders" (ARND) with predominant neurotoxic effects and a large spectrum of cerebral dysfunctions are manifold more frequent than the full-blown FAS. These remain mostly unrecognized, overlooked and they are difficult to be diagnosed, the symptoms being unspecific. Alcohol in pregnancy is nowadays the most important and the most frequent toxic substance for the embryo and the fetus and one of the most frequent causes of mental retardation. The longlasting and irreversible consequences refer to school development, social maturation, social behaviour and later life-style. The diagnosis is based on the careful maternal history and on the clinical findings; there are no biochemical parameters of assessment. The risk of addiction development in these children is assumed to be more than 20 percent.

Adolescent↗

PubMed2005

[Drug use in pregnancy].

Drug use in pregnancy is associated with a number of serious complications for mother and fetus. There are safe data on destructive effects of alcohol, cocain, marijuana and tobacco on pregnancy and neonatal outcome. Of importance is the fact that for many drugs similar effects on pregnancy could be observed: vasoconstriction of the placental vessels resulting in placental abruption, preterm labour (mother), spontaneous abortion, intrauterine growth retardation, low birth weight, preterm delivery and stillbirth (fetus). Symptoms of withdrawal and neurodevelopmental disorders are the most important problems of the neonate. However, only small data exist about the effects of recently popular party drugs like ecstasy or LSD. In addition, from most drugs, with exception of alcohol, safe information about the risk of congenital malformations doesn't exist. Nevertheless they may be a useful guide in the diagnostic of potential malformations by ultrasound. Most of pregnant women using drugs are poly-drug users and are often in reduced general condition. They need therefore the intensive care of the obstetrician in cooperation with other specialists (internal medicine, psychiatry).

Abnormalities, Drug-Induced↗

PubMed2002

De novo MECP2 frameshift mutation in a boy with moderate mental retardation, obesity and gynaecomastia.

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the MECP2 gene, with apparent lethality in male embryos. However, recent studies indicate that mutations in the MECP2 gene can cause congenital encephalopathy, an Angelman-like phenotype and even nonspecific mental retardation in males. We report on a 10-year-old boy with moderate mental retardation, hypotonia, obesity and gynaecomastia and a de novo 2-bp deletion in the MECP2 gene that resulted in a frameshift and premature stop codon. As some of the clinical features were suggestive of the Prader-Willi syndrome, it might be worthwhile screening for MECP2 mutations in patients with an atypical Prader-Willi phenotype but without the characteristic abnormalities on chromosome 15q. This report contributes to the phenotypic knowledge of male patients with MECP2 mutations. Moreover, this is the first reported male case of a de novo MECP2 mutation.

Child↗

PubMed2002

Transgenic and knock-out mouse pups: the growing need for behavioral analysis.

Few laboratories working with transgenic and knockout mice analyze the neurobehavioral consequences of genetic manipulation in early ontogeny. However, the study of behavioral endpoints during the early postnatal period in genetically modified mice is important not only to assess possible developmental abnormalities, but also to better understand and disentangle the effects of genetic manipulations in adulthood. We propose that the assessment of neurobehavioral development represents an appropriate strategy to identify possible compensatory and/or unexpected effects. Nowadays, a large number of experimental protocols that take into account the practical constraints imposed by the peculiar physiological and behavioral responses of an immature subject are available to assess the neurobehavioral profile of developing mice. While this knowledge should be applied to the field of transgenic and knock-out mice in general, it should be recommended, in particular, for the study of mouse models of neurodevelopmental disorders.

Animals↗

PubMed1991

A general theory concerning the prenatal origins of cerebral lateralization in humans.

The origins of cerebral lateralization in humans are traced to the asymmetric prenatal development of the ear and labyrinth. Aural lateralization is hypothesized to result from an asymmetry in craniofacial development, whereas vestibular dominance is traced to the position of the fetus during the final trimester. A right-ear sensitivity advantage may contribute to a left-hemispheric advantage in speech perception and language functions, whereas left-otolithic dominance may independently promote right-sided motoric dominance and a right-hemispheric superiority in most visuospatial functions. The emergence of handedness is linked to the assumption of an upright posture in the early hominids, whereas the failure to develop clear vestibular asymmetry may underlie the poor motoric lateralization found in several neurodevelopmental disorders.

Afferent Pathways↗