Evaluation of the child with idiopathic mental retardation

Screening Children's Intellectual Disabilities with Phonetic Features, Facial Phenotype and Craniofacial Variability Index

BACKGROUND

Intellectual Disability (ID) is a kind of developmental deficiency syndrome caused by congenital diseases or postnatal events. This syndrome could be intervened as soon as possible if its early screening was efficient, which may improve the condition of patients and enhance their self-care ability. The early screening of ID is always achieved by clinical interview, which needs in-depth participation of medical professionals and related medical resources.

METHODS

A new method for screening ID has been proposed by analyzing the facial phenotype and phonetic characteristic of young subjects. First, the geometric features of subjects' faces and phonetic features of subjects' voice are extracted from interview videos, then craniofacial variability index (CVI) is calculated with the geometric features and the risk of ID is given with the measure of CVI. Furthermore, machine learning algorithms are utilized to establish a method for further screening ID based on facial features and phonetic features.

RESULTS

The proposed method using three feature sets, including geometric features, CVI features and phonetic features was evaluated. The best performance of accuracy was closer to 80%.

CONCLUSIONS

The results using the three feature sets revealed that the proposed method may be applied in a clinical setting in the future after continuous improvement.

A lightweight CNN and Transformer hybrid model for mental retardation screening among children from spontaneous speech

Mental retardation (MR) is a group of mental disorders characterized by low intelligence and social adjustment difficulties. Early diagnosis is beneficial for the timely intervention of children with MR to ease the degree of disability. Children with MR always have impaired speech functions compared to normal children, which is significant for clinical diagnosis. On the basis of this, our study proposes a spontaneous speech-based framework (MT-Net) for screening MR, which merges mobile inverted bottleneck convolutional blocks (MBConv) and visual Transformer blocks. MT-Net takes log-mel spectrograms converted from raw interview speech as data source, and utilizes MBConv and visual Transformer to learn low-level and high-level features well. In addition, SpecAugment, a data augmentation strategy, has been used to expand our audio dataset to further enhance the performance of MT-Net. The experimental results show that our proposed MT-Net outperforms Transformer networks (ViT) and convolutional neural networks (ResNet18, MobileNetV2, EfficientNetV2), achieving accuracy of 91.60% after using SpecAugment. Our proposed MT-Net has fewer parameters, low computing consumption and high prediction accuracy, which is expected to be an auxiliary screening tool for MR.

Genetic Testing in Neurodevelopmental Disorders

Neurodevelopmental disorders are the most prevalent chronic medical conditions encountered in pediatric primary care. In addition to identifying appropriate descriptive diagnoses and guiding families to evidence-based treatments and supports, comprehensive care for individuals with neurodevelopmental disorders includes a search for an underlying etiologic diagnosis, primarily through a genetic evaluation. Identification of an underlying genetic etiology can inform prognosis, clarify recurrence risk, shape clinical management, and direct patients and families to condition-specific resources and supports. Here we review the utility of genetic testing in patients with neurodevelopmental disorders and describe the three major testing modalities and their yields - chromosomal microarray, exome sequencing (with/without copy number variant calling), and FMR1 CGG repeat analysis for fragile X syndrome. Given the diagnostic yield of genetic testing and the potential for clinical and personal utility, there is consensus that genetic testing should be offered to all patients with global developmental delay, intellectual disability, and/or autism spectrum disorder. Despite this recommendation, data suggest that a minority of children with autism spectrum disorder and intellectual disability have undergone genetic testing. To address this gap in care, we describe a structured but flexible approach to facilitate integration of genetic testing into clinical practice across pediatric specialties and discuss future considerations for genetic testing in neurodevelopmental disorders to prepare pediatric providers to care for patients with such diagnoses today and tomorrow.

Cochlear Implantation Outcomes in Children with Agenesis of the Corpus Callosum: A Retrospective Study and A Review of the Literature

OBJECTIVES

The aim of the present study was to analyze the outcomes of cochlear implantation (CI) in patients with agenesis of the corpus callosum (CCA). A literature review and a retrospective analysis of our cochlear implant database were performed.

MATERIALS AND METHODS

To the best of our knowledge, in the English literature, there was only one case reported with CCA who had undergone CI surgery. This case had Donnai-Barrow syndrome. In the Cukurova University School of Medicine Department of Otorhinolaryngology database, 5 of the 1317 patients who underwent CI surgery who had CCA were selected. The patients' demographic characteristics, operative findings, surgical outcomes, and additional disabilities were investigated. The patients' preoperative and postoperative Listening Progress Profile (LiP) and Meaningful Auditory Integration Scale (MAIS) tests were done to analyze the auditory performances.

RESULTS

The participants of the study were 5 (0.38%) individuals (2 male and 3 female patients; ages 5.5, 7.5, 8, 9, and 12 years). Two of the patients had total agenesis, and the other three had partial agenesis of the CCA. In the histories of the patients, one patient had parental consanguinity, and one had febrile convulsion. No patient had an additional disability. None had experienced device failure. No patients were non-users or limited users of cochlear implants. Postoperative LiP and MAIS test scores were improved for all patients nearly as the patients without any deformity. They showed normal auditory performance in the analysis in their postoperative 48 months of follow-up.

CONCLUSION

Patients who had CCA are good candidates for CI surgery.

PAK3 mutations responsible for severe intellectual disability and callosal agenesis inhibit cell migration

Corpus callosum agenesis (CCA) is a brain malformation associated with a wide clinical spectrum including intellectual disability (ID) and an etiopathological complexity. We identified a novel missense G424R mutation in the X-linked p21-activated kinase 3 (PAK3) gene in a boy presenting with severe ID, microcephaly and CCA and his fetal sibling with CCA and severe hydrocephaly. PAK3 kinase is known to control synaptic plasticity and dendritic spine dynamics but its implication is less characterized in brain ontogenesis. In order to identify developmental functions of PAK3 impacted by mutations responsible for CCA, we compared the biochemical and biological effects of three PAK3 mutations localized in the catalytic domain. These mutations include two "severe" G424R and K389N variants (responsible for severe ID and CCA) and the "mild" A365E variant (responsible for nonsyndromic mild ID). Whereas they suppressed kinase activity, only the two severe variants displayed normal protein stability. Furthermore, they increased interactions between PAK3 and the guanine exchange factor αPIX/ARHGEF6, disturbed adhesion point dynamics and cell spreading, and severely impacted cell migration. Our findings highlight new molecular defects associated with mutations responsible for severe clinical phenotypes with developmental brain defects.

Importance of pedigree in patients with familial epilepsy and intellectual disability

In this study, we prospectively evaluated demographic characteristics, clinical findings and pedigree patterns in 70 patients with familial epilepsy and/or intellectual disability (ID)/global developmental delay (GDD) and/or motor retardation but without specific etiologic diagnosis to determine genetic inheritance patterns by using at least a three-generation pedigree analysis. Mean age of the patients was 6.85 ± 3.93 years and male/female ratio was 1.50. There was consanguinity between the parents of 47 (67.1%) patients. Only epilepsy was diagnosed in 14 patients; only ID/GDD in 22; epilepsy and ID/GDD in 9 and epilepsy and ID/GDD and motor retardation in 25 patients. Genetic inheritance pattern was definitely determined in 60 (85.7%) patients, and most of the patients (61.4%) displayed autosomal recessive inheritance. Based on our findings, we suggest that a three-generation pedigree analysis should be obtained in all patients with familial neurological disorders, including epilepsy, ID/GDD and motor retardation, to optimise counselling, screening and diagnostic testing.

Genome-Wide Array Analysis Reveals Novel Genomic Regions and Candidate Gene for Intellectual Disability

INTRODUCTION

Intellectual disability (ID) is often sporadic, and its complex etiology makes clinical diagnosis extremely difficult.

OBJECTIVE

The aims of this study were to detect copy number variations (CNVs) in patients with ID and to analyze the correlation between pathogenic CNVs and clinical phenotype.

METHODS

After cases of ID caused by metabolic dysfunction or environmental factors were excluded, 64 patients with moderate to severe ID were enrolled. Karyotype and single nucleotide polymorphism (SNP) array analyses were performed for all patients. The relationship between CNVs and phenotype was identified with genotype-phenotype comparisons and by searching CNV databases.

RESULTS

Karyotype analysis showed four patients with chromosomal aneuploidy and seven with chromosomal structural abnormality. After excluding the four cases with chromosomal aneuploidy, the remaining 60 cases were analyzed using SNP array. The results revealed 87 CNVs in 45 cases, including 16 pathogenic CNVs in 12 individuals, with a diagnostic yield of 20.0% (12/60). We found large deletions at 16q22.2q23.1 and 3q24q25.32 in two patients, respectively, in whom specific syndromes had not been defined. Our array analysis showed one case carried a 210 kb deletion at 1p21.2p21.3, which included only one coding gene LPPR4, which might be a candidate gene for ID phenotype.

CONCLUSIONS

Use of the genome-wide array method can improve the detection rate of CNVs, reveal chromosomal abnormalities that have not been well-characterized by cytology, and provide a new way to locate genes for patients with the ID phenotype. Interpretation of CNVs remains a major challenge. Sharing of CNVs and phenotype information from different laboratories in public databases is important.

[Massive parallel sequencing for molecular-genetic diagnosis of mental retardation]

Gene mutations occur with high frequency in children with mental retardation. Standard diagnostic methods, such as TMS, Sanger's sequencing of individual genes, MLPA analysis of deletions, and investigation of methylation status in Martin-Bell syndrome are not informative in the majority of cases that hampered further diagnostic efforts. Massive parallel sequencing (MPS) allowed physicians to continue diagnostic search in previously undiagnosed cases and to find molecular causes of disease. MPS permits to discover a large number of new genes and understand the pathogenesis of mental retardation and brain development more deeply. It became possible to perform prenatal and pre-implantation diagnostics. However, big data generate big problems with their interpretation the genetic counselor faces with. This review reflects the advantages and disadvantages of MPS. Different variants of MPS, including gene panels, whole exome and whole genome sequencing as well as sequencing of trios, are described. In addition, the authors discuss the difficulties of interpretation of the results and recommendations for obtaining the most accurate results.

Copy Number Variations Found in Patients with a Corpus Callosum Abnormality and Intellectual Disability

OBJECTIVE

To evaluate the role that chromosomal micro-rearrangements play in patients with both corpus callosum abnormality and intellectual disability, we analyzed copy number variations (CNVs) in patients with corpus callosum abnormality/intellectual disability STUDY DESIGN: We screened 149 patients with corpus callosum abnormality/intellectual disability using Illumina SNP arrays.

RESULTS

In 20 patients (13%), we have identified at least 1 CNV that likely contributes to corpus callosum abnormality/intellectual disability phenotype. We confirmed that the most common rearrangement in corpus callosum abnormality/intellectual disability is inverted duplication with terminal deletion of the 8p chromosome (3.2%). In addition to the identification of known recurrent CNVs, such as deletions 6qter, 18q21 (including TCF4), 1q43q44, 17p13.3, 14q12, 3q13, 3p26, and 3q26 (including SOX2), our analysis allowed us to refine the 2 known critical regions associated with 8q21.1 deletion and 19p13.1 duplication relevant for corpus callosum abnormality; report a novel 10p12 deletion including ZEB1 recently implicated in corpus callosum abnormality with corneal dystrophy; and) report a novel pathogenic 7q36 duplication encompassing SHH. In addition, 66 variants of unknown significance were identified in 57 patients encompassed candidate genes.

CONCLUSIONS

Our results confirm the relevance of using microarray analysis as first line test in patients with corpus callosum abnormality/intellectual disability.

Genetic Approach to Diagnosis of Intellectual Disability

Intellectual disability is a non-specific phenotype present in a genetically heterogeneous group of disorders. It is characterized by deficits in intellectual and adaptive functioning, presenting before 18 y of age. Identifying the cause of ID is important to provide treatment where available, genetic counseling, recurrence risks and reproductive options for subsequent pregnancies. Advances in technology, especially next generation sequencing and microarrays, have greatly increased the diagnostic yield of evaluation in cases of ID. This paper describes the points in history taking and examination in the evaluation of a proband, and discusses the proper use of newer diagnostic technologies.

Outcomes Associated With Isolated Agenesis of the Corpus Callosum: A Meta-analysis

CONTEXT

Antenatal counseling in cases of agenesis of the corpus callosum (ACC) is challenging.

OBJECTIVES

To ascertain the outcome in fetuses with isolated complete ACC and partial ACC.

DATA SOURCES

Medline, Embase, CINAHL, and Cochrane databases.

STUDY SELECTION

Studies reporting a prenatal diagnosis of ACC. The outcomes observed were: chromosomal abnormalities at standard karyotype and chromosomal microarray (CMA) analysis, additional anomalies detected only at prenatal MRI and at postnatal imaging or clinical evaluation, concordance between prenatal and postnatal diagnosis and neurodevelopmental outcome.

DATA EXTRACTION

Meta-analyses of proportions were used to combine data.

RESULTS

Twenty-seven studies were included. In cACC, chromosomal anomalies occurred in 4.81% (95% confidence interval [CI], 2.2-8.4) of the cases. Gross and fine motor control were abnormal in 4.40% (95% CI, 0.6-11.3) and 10.98% (95% CI, 4.1-20.6) of the cases, respectively, whereas 6.80% (95% CI, 1.7-14.9) presented with epilepsy. Abnormal cognitive status occurred in 15.16% (95% CI, 6.9-25.9) of cases. In partial ACC, the rate of chromosomal anomalies was 7.45% (95% CI, 2.0-15.9). Fine motor control was affected in 11.74% (95% CI, 0.9-32.1) of the cases, and 16.11% (95% CI, 2.5-38.2) presented with epilepsy. Cognitive status was affected in 17.25% (95% CI, 3.0-39.7) of cases.

LIMITATIONS

Different neurodevelopmental tools and time of follow-up of the included studies.

CONCLUSIONS

Children wih a prenatal diagnosis of isolated ACC show several degrees of impairment in motor control, coordination, language, and cognitive status. However, in view of the large heterogeneity in outcomes measures, time at follow-up, and neurodevelopmental tools used, large prospective studies are needed to ascertain the actual occurrence of neuropsychological morbidity of children with isolated ACC.

Clinical Genetic Aspects of ASD Spectrum Disorders

Early presumptions opined that autism spectrum disorder (ASD) was related to the rearing of these children by emotionally-distant mothers. Advances in the 1960s and 1970s clearly demonstrated the biologic basis of autism with a high heritability. Recent advances have demonstrated that specific etiologic factors in autism spectrum disorders can be identified in 30%–40% of cases. Based on early reports newer, emerging genomic technologies are likely to increase this diagnostic yield to over 50%. To date these investigations have focused on etiologic factors that are largely mono-factorial. The currently undiagnosed causes of ASDs will likely be found to have causes that are more complex. Epigenetic, multiple interacting loci, and four dimensional causes (with timing as a variable) are likely to be associated with the currently unidentifiable cases. Today, the “Why” is more important than ever. Understanding the causes of ASDs help inform families of important issues such as recurrence risk, prognosis, natural history, and predicting associated co-morbid medical conditions. In the current era of emerging efforts in “personalized medicine”, identifying an etiology will be critical in identifying endo-phenotypic groups and individual variations that will allow for tailored treatment for persons with ASD.

Comprehensive evaluation of the child with intellectual disability or global developmental delays

Global developmental delay and intellectual disability are relatively common pediatric conditions. This report describes the recommended clinical genetics diagnostic approach. The report is based on a review of published reports, most consisting of medium to large case series of diagnostic tests used, and the proportion of those that led to a diagnosis in such patients. Chromosome microarray is designated as a first-line test and replaces the standard karyotype and fluorescent in situ hybridization subtelomere tests for the child with intellectual disability of unknown etiology. Fragile X testing remains an important first-line test. The importance of considering testing for inborn errors of metabolism in this population is supported by a recent systematic review of the literature and several case series recently published. The role of brain MRI remains important in certain patients. There is also a discussion of the emerging literature on the use of whole-exome sequencing as a diagnostic test in this population. Finally, the importance of intentional comanagement among families, the medical home, and the clinical genetics specialty clinic is discussed.

A refined approach to evaluating global developmental delay for the international medical community

BACKGROUND

Global developmental delay is usually defined as significant delay in two or more domains of development. Etiologic diagnosis generally proves difficult and the etiology remains undetermined in up to 62% of these children. Those in whom an etiology is established generally undergo an exhaustive and costly diagnostic evaluation, even though this may not change the medical or therapeutic management of the delay. The history and physical examination may provide up to 40% of etiologic diagnoses if adequately conducted.

METHODS

We performed a critical review of the literature on global developmental delay via PubMed.

RESULTS

Five major etiologic categories for global developmental delay were identified and traits of the history and physical examination suggestive for their diagnosis were described. Additionally, current diagnostic tools and their benefits and limitations were appraised.

CONCLUSIONS

We propose an improved approach to enhance clinical diagnosis in both resource-rich and resource-limited settings favoring early intervention and management.

Agenesis of the corpus callosum: a clinical approach to diagnosis

This review article aims to guide the clinician in establishing a diagnosis in patients with agenesis of the corpus callosum (ACC), presenting antenatally or postnatally. ACC may be isolated, or occur in association with other neuroanatomical lesions and/or congenital anomalies, and has many different genetic causes. Neuropsychological outcome varies considerably from normal to profound intellectual disability depending on the etiology. Approximately 25% of individuals with antenatally diagnosed apparently isolated ACC have intellectual disability. Subtle neurological, social, and learning deficits may still occur in those with normal intelligence and longitudinal neurocognitive follow-up is recommended for all children with ACC. The finding of ACC should prompt detailed clinical assessment in order to determine and manage the underlying condition. It is recognized that genetic factors contribute to ACC in the vast majority of cases. Less commonly ACC can result from antenatal infections, vascular or toxic insults, and it is increasingly recognized that ACC, particularly isolated ACC, may be due to an interaction of a number of "modifier" genetic and environmental factors. There are a large number of genetic conditions in which ACC may be a feature. We suggest a diagnostic algorithm to help guide the clinician towards diagnosis, to provide outcome advice and to aid in genetic counseling.

Confirmation of chromosomal microarray as a first-tier clinical diagnostic test for individuals with developmental delay, intellectual disability, autism spectrum disorders and dysmorphic features

BACKGROUND AND OBJECTIVES

Submicroscopic chromosomal rearrangements are the most common identifiable causes of intellectual disability and autism spectrum disorders associated with dysmorphic features. Chromosomal microarray (CMA) can detect copy number variants <1 Mb and identifies size and presence of known genes. The aim of this study was to demonstrate the usefulness of CMA, as a first-tier tool in detecting the etiology of unexplained intellectual disability/autism spectrum disorders (ID/ASDs) associated with dysmorphic features in a large cohort of pediatric patients.

PATIENTS AND METHODS

We studied 349 individuals; 223 males, 126 females, aged 5 months-19 years. Blood samples were analyzed with CMA at a resolution ranging from 1 Mb to 40 Kb. The imbalance was confirmed by FISH or qPCR. We considered copy number variants (CNVs) causative if the variant was responsible for a known syndrome, encompassed gene/s of known function, occurred de novo or, if inherited, the parent was variably affected, and/or the involved gene/s had been reported in association with ID/ASDs in dedicated databases.

RESULTS

91 CNVs were detected in 77 (22.06%) patients: 5 (6.49%) of those presenting with borderline cognitive impairment, 54 (70.13%) with a variable degree of DD/ID, and 18/77 (23.38%) with ID of variable degree and ASDs. 16/77 (20.8%) patients had two different rearrangements. Deletions exceeded duplications (58 versus 33); 45.05% (41/91) of the detected CNVs were de novo, 45.05% (41/91) inherited, and 9.9% (9/91) unknown. The CNVs caused the phenotype in 57/77 (74%) patients; 12/57 (21.05%) had ASDs/ID, and 45/57 (78.95%) had DD/ID.

CONCLUSIONS

Our study provides further evidence of the high diagnostic yield of CMA for genetic testing in children with unexplained ID/ASDs who had dysmorphic features. We confirm the value of CMA as the first-tier tool in the assessment of those conditions in the pediatric setting.

Evaluation children with global developmental delay: a prospective study at sultan qaboos university hospital, oman

OBJECTIVE

A prospective study was designed to analyze risk factors and clinical features in children with global developmental delay (GDD) at our hospital. No previous data is available on GDD from Oman.

METHODS

This study was conducted at Sultan Qaboos University Hospital from January 2008 until June 2009. All the children aged 5 years or less, referred with suspected GDD were included in the study. Data was analyzed to determine the underlying etiology. The children with neurodegenerative disease and muscular dystrophy were excluded from the study.

RESULTS

One hundred and ten children, 59 males (53.6%) and 51 females (46.4%) were included in the study. The mean age at initial evaluation was 13.29 months. An underlying etiology was determined in 79 (71.8%) children. Perinatal history was associated with significant difference in detection of etiology (p=0.039). Abnormal neurological examination was a significant factor in detection of the underlying etiology. Magnetic resonance imaging (MRI) in 105 children and metabolic screening in 93 children were the most frequently ordered investigations. Abnormal imaging, MRI (p=0.001), CT scan (p=0.036) and metabolic screening (p=0.034) were significantly associated with detection of etiology.

CONCLUSION

Etiology was detected in 71.8% of the children. MRI was the most significant investigation to detect the abnormality.

Microarray as a first genetic test in global developmental delay: a cost-effectiveness analysis

AIM

Microarray technology has a significantly higher clinical yield than karyotyping in individuals with global developmental delay (GDD). Despite this, it has not yet been routinely implemented as a screening test owing to the perception that this approach is more expensive. We aimed to evaluate the effect that replacing karyotype with array-based comparative genomic hybridization (aCGH) would have on the total cost of the workup for GDD.

METHOD

We evaluated the cost-effectiveness of aCGH compared with karyotyping by retrospectively analysing the cost of workup in a cohort of 114 children (69 males; 45 females) representing a consecutive series of children diagnosed with GDD.

RESULTS

The average increase in cost if aCGH had been performed instead of karyotyping as a first test was $442 per individual when performed by a private company (98% confidence interval $238-604). In contrast, $106 (98% confidence interval -$17 to $195) would have been saved if aCGH was performed locally in a laboratory already possessing the required technology. The incremental cost per additional diagnosis was estimated to be $12,874 if aCGH was performed in a private laboratory, but <$1379 if performed locally. (Costs reported in Canadian dollars, using 2010 prices.)

INTERPRETATION

aCGH would be cost-effective as a first genetic test in the clinical evaluation of individuals with GDD.

Magnetic resonance imaging and proton magnetic resonance spectroscopy of the brain in the diagnostic evaluation of developmental delay

AIM

To assess the contribution of MRI and proton spectroscopy (1HMRS) in establishing an etiological diagnosis in children with developmental delay (DD) and to assess whether the chance of finding specific abnormalities correlates with the presence of neurological signs and/or abnormal head circumference (HC).

METHODS

Patients were derived from a cohort of 325 consecutive patients with DD receiving structured multidisciplinary evaluation in our centre. Patients had MRI/1HMRS if a diagnosis could not be made clinically and if additional neurological signs and/or abnormal HC and/or an IQ below 50 were present. The MRI protocol consisted of axial IR, T2, FLAIR, sagittal T1 and coronal T2 sequences. Multivoxel 1HMRS was located in a plane superior to the lateral ventricles with voxels in both grey matter and white matter.

RESULTS

One hundred and nine children were scanned, 80 of them because of neurological signs and/or abnormal HC. Although minor abnormalities were noted in the vast majority of patients, MRI and/or 1HMRS really contributed to an etiological diagnosis in only 10 (9%) patients, all of whom were scanned because of neurological signs. In these 10 patients, 1HMRS was diagnostic in one patient and of additional value to MRI findings in 3 patients.

CONCLUSIONS

MRI and 1HMRS may contribute to the diagnostic evaluation of DD, especially if applied specifically to patients with neurological signs, whereas its role is very limited in children without these signs.

Agenesis of the corpus callosum in California 1983-2003: a population-based study

The objective of this study was to characterize the prevalence, demographic risk factors, and malformations associated with agenesis and hypoplasia of the corpus callosum diagnosed in infancy. Using a large population-based registry of birth defects, we ascertained 630 cases of agenesis (ACC) and hypoplasia (HCC) of the corpus callosum diagnosed in the first year of life among 3.4 million live births from 1983 to 2003. Infants with destructive lesions or specific complex central nervous system (CNS) malformations (neural tube defects, lissencephaly, and holoprosencephaly) were excluded. Multivariable Poisson regression analysis was used to examine demographic risk factors. The combined prevalence of ACC and HCC was 1.8 per 10,000 live births. Fifty-two percent of cases were male. Infants with ACC had an almost fourfold higher prevalence among infants born prematurely when compared with children born > or =37 weeks gestation (RR 3.7, 95% CI 2.5-5.3). After adjusting for paternal age, advanced maternal age >/=40 years was associated with ACC in infants with a chromosomal disorder (ACC RR 5.9; 95% CI 1.8-19.3, HCC RR 3.5; 95% CI 0.9-14.1). Paternal age was not significantly associated with ACC after adjusting for maternal age. Callosal anomalies were often seen in the context of a chromosomal abnormality (17.3%) and with accompanying somatic (musculoskeletal 33.5% and cardiac 27.6%) and CNS malformations (49.5%). Callosal anomalies form a clinically significant and relatively frequent group of malformations of the CNS that are associated with increased risk of premature birth, are more common with advanced maternal age and are frequently part of a complex, multisystem disorder.

Array comparative genomic hybridization in global developmental delay

OBJECTIVE

Array-based comparative genomic hybridization (array CGH) is an emerging technology that allows for the genome-wide detection of DNA copy number changes (CNC) such as deletions or duplications. In this study, array-based CGH was applied to a consecutive series of children with previously undiagnosed non-syndromal global developmental delay (GDD) to assess potential etiologic yield.

METHODS

The children in this study were drawn from a previously reported consecutive series of children with well-defined GDD. Almost all subjects had undergone prior karyotyping and neuroimaging studies with non-diagnostic results. Array-based CGH was undertaken using the SignatureChip(R) (1887 BACs representing 622 loci) with abnormalities verified by subsequent FISH analysis and testing of parents to distinguish between pathogenic and familial non-pathogenic variants.

RESULTS

On CGH analysis in our study, 6 of 94 children (6.4%) had a causally related pathogenic CNC. Three were sub-telomeric in location. An analysis of a variety of clinical factors revealed that only the presence of minor dysmorphic features (<3) was predictive of etiologic yield on CGH analysis (4/26 vs. 2/68, P = 0.05). Severity of delay was not found to be predictive.

INTERPRETATION

In children with non-syndromal GDD, array-based CGH has an etiologic yield of 6.4%. This suggests that this emerging technology may be of diagnostic value when applied subsequent to detailed history, physical examination, and targeted laboratory testing. Array CGH may merit consideration as a first-tier test in the context of a child with unexplained GDD.

Global developmental delay and mental retardation or intellectual disability: conceptualization, evaluation, and etiology

Global developmental delay and mental retardation or intellectual disability offer challenges to the practitioner at several different levels. Accurate recognition of these most common of subtypes of neurodevelopmental disabilities is a central precondition to their correct evaluation and management. Proper evaluation is a time- and labor-intensive process that emphasizes several different goals. Guidelines now exist to assist the practitioner in selecting the appropriate investigation path to be pursued, and these guidelines should be used to inform the selections of investigations made. Although challenging and time consuming, the evaluation of these children offers many professional rewards and is a necessary first step in a family's adaptation to their child's chronic condition.

Genetic evaluation of intellectual disabilities

All children with an intellectual disability (mental retardation) or global developmental delay should have a comprehensive evaluation to establish the etiology of the disability. A specific etiologic diagnosis offers the opportunity to discuss treatment, prognosis, and genetic recurrence risk. A diagnosis also avoids unnecessary testing and can lead to opportunities for improved health and functional outcomes. The key elements of the diagnostic evaluation are the medical and developmental history, 3-generation family history, dysmorphologic examination, neurologic examination, and judicious use of the laboratory and neuroimaging. All published guidelines for the evaluation of children with intellectual disability acknowledge that there is a substantial percentage of patients who are undiagnosed after a comprehensive evaluation and who deserve ongoing follow-up for the purpose of establishing a diagnosis. Recently, studies of the clinical application of array comparative genomic hybridization (aCGH) to individuals with intellectual disability indicate that this approach provides a diagnosis in as much as 10% of patients and that this technique is replacing the use of fluorescent in situ hybridization for subtelomere imbalances now used for such patients when the standard karyotype is normal. The literature suggests that history and examination by an expert clinician will lead to a diagnosis in 2 of 3 patients in whom a diagnosis is made. Laboratory studies alone, including neuroimaging, provide a diagnosis in the remaining one third. The approach to the evaluation of the patient in whom an etiologic diagnosis is not suspected after the history and physical examinations includes a standard karyotype, Fragile X molecular genetic testing, aCGH, and neuroimaging, based on the evidence to date. One can expect rapid changes in the microarray technology in the near future.

Why do we need a diagnosis? A qualitative study of parents' experiences, coping and needs, when the newborn child is severely disabled

BACKGROUND

Communication with parents who are realizing their child is severely disabled is a difficult task for professionals. Parents are experiencing great emotional stress during the diagnostic process and dissatisfaction with disclosure is widespread. The aim of this study was to investigate parents' reactions when realizing their child's disability, the impact of the diagnosis and parents' ways of coping.

METHODS

This was a qualitative, longitudinal study, using in-depth interviews with 16 parents of a physically and mentally disabled child who had recently been diagnosed as such. Children's age at inclusion ranged from 1 to 27 months. Half of the children had an unknown diagnosis. Data were analysed using the Grounded Theory method.

RESULTS

were validated and approved by the interviewed parents.

RESULTS

The certainty of the diagnosis was central for parents' experiences. First, the emotional reaction of the parents is highly influenced by the diagnostic process. Second, parents needed possibilities for taking action, and third they found difficulty in coping with an uncertain future. These three themes all related to the meaning that parents ascribed to the stating of a diagnosis. Parents' needs in relation to communication were identified as equality in co-operation with doctors, an empathic professional approach, and the child being seen with possibilities despite his or her disabilities.

CONCLUSIONS

Parents' process of realization was related to the diagnostic process, and information and communication should be individualized accordingly. Parents wanted to co-operate and they needed possibilities for active coping with their situation.

Neuroimaging of the child with developmental delay

Developmental delay (DD) affects approximately 1% to 3% of all children in the United States. This diagnosis significantly impedes quality of life and full participation in the life of the family, school, and community. In this setting, the clinician's ability to detect, diagnose, and possibly treat the cause for DD in a timely manner depends on a multimodality approach to neuroimaging and a robust understanding of the various imaging algorithms aimed at determining the etiology of disease, structural and/or anatomic defects, functional activity, metabolic profiles, and genetic characteristics. Taken separately and in combination, these features are effectively depicted and analyzed using an array of brain imaging modalities: ultrasound, computed tomography, nuclear medicine, magnetic resonance (MR) spectroscopy, and a growing mix of sophisticated MR imaging (MRI) techniques, including diffusion-weighted imaging, diffusion tensor imaging, perfusion MRI, and functional MRI. Thus, equipped with these advanced imaging capabilities, pediatric neurologists and neuroradiologists are now positioned to diagnose with greater accuracy and speed; this, in turn, results in more effective treatment plans and improved patient outcomes as measured by progress in reaching developmental milestones and in ameliorating secondary conditions such as seizures, poor motor control, incontinence, and impulsivity. The purpose of this article is to present the numerous causes of pediatric DD, describe their respective neuroimaging findings, discuss various neuroimaging approaches for elucidating etiology, and offer specific guidelines for optimizing imaging results in the setting of multimodality imaging capabilities.

Investigation of global developmental delay

The investigation of global developmental delay in preschool children varies between centres and between paediatricians. Following a literature search and review of the evidence base, guidelines were developed to assist in the assessment and management of such children presenting to secondary level services. Evidence supporting the use of genetic and biochemical investigations on a screening basis was found, but there was no evidence to support the use of metabolic investigations or neuroimaging in the absence of other positive findings on history or examination. Detailed history and examination are paramount in the assessment of children with global developmental delay. Investigations can be a useful adjunct in determining aetiology. Evidence based guidelines have been developed to assist doctors in the selection of appropriate investigations for this group of children.

Analysis of clinical features predicting etiologic yield in the assessment of global developmental delay

OBJECTIVE

Global developmental delay is a common reason for presentation for neurologic evaluation. This study examined the role of clinical features in predicting the identification of an underlying cause for a child's global developmental delay.

METHODS

Over a 10-year inclusive interval, the case records of all consecutive children <5 years of age referred to a single ambulatory practice setting for global developmental delay were systematically reviewed. The use of clinical features in predicting the identification of a specific underlying cause for a child's delay was tested using chi2 analysis.

RESULTS

A total of 261 patients eventually met criteria for study inclusion. Mean age at initial evaluation was 33.6 months. An underlying cause was found in 98 children. Commonest etiologic groupings were genetic syndrome/chromosomal abnormality, intrapartum asphyxia, cerebral dysgenesis, psychosocial deprivation, and toxin exposure. Factors associated with the ability to eventually identify an underlying cause included female gender (40 of 68 vs 58 of 193), abnormal prenatal/perinatal history (52 of 85 vs 46 of 176), absence of autistic features (85 of 159 vs 13 of 102), presence of microcephaly (26 of 40 vs 72 of 221), abnormal neurologic examination (52 of 71 vs 46 of 190), and dysmorphic features (44 of 84 vs 54 of 177). In 113 children without any abnormal features identified on history or physical examination, routine screening investigations (karyotype, fragile X molecular genotyping, and neuroimaging) revealed an underlying etiology in 18.

CONCLUSIONS

Etiologic yield in an unselected series of young children with global developmental delay is close to 40% overall and 55% in the absence of any coexisting autistic features. Clinical features are readily apparent that may enhance an expectation of a successful etiologic search. Screening investigations may yield an underlying cause.

Clinical genetic evaluation of the child with mental retardation or developmental delays

This clinical report describes the clinical genetic evaluation of the child with developmental delays or mental retardation. The purpose of this report is to describe the optimal clinical genetics diagnostic evaluation to assist pediatricians in providing a medical home for children with developmental delays or mental retardation and their families. The literature supports the benefit of expert clinical judgment by a consulting clinical geneticist in the diagnostic evaluation. However, it is recognized that local factors may preclude this particular option. No single approach to the diagnostic process is supported by the literature. This report addresses the diagnostic importance of clinical history, 3-generation family history, dysmorphologic examination, neurologic examination, chromosome analysis (> or =650 bands), fragile X molecular genetic testing, fluorescence in situ hybridization studies for subtelomere chromosome rearrangements, molecular genetic testing for typical and atypical presentations of known syndromes, computed tomography and/or magnetic resonance brain imaging, and targeted studies for metabolic disorders.

Imagerie par résonance magnétique du retard mental non spécifique

Mental retardation is considered idiopathic or not otherwise specified when no etiological diagnosis can be identified in spite of comprehensive history, physical examination and metabolic or genetic investigations. In such cases, brain MRI is indicated for patients with abnormal head size or shape, craniofacial malformation, somatic anomalies, neurocutaneous findings, seizures, focal neurological findings or behavioral and/or developmental problems. Brain anomalies are now considered a main category for the etiology of mental retardation. MRI evaluation should include axial images of the entire brain, sagittal images through the midline structures, and coronal images of the posterior fossa or entire brain. MRI allows detection of major and or minor cerebral anomalies or malformations, sometimes multiple. In the literature, the most frequently involved structures include: 1/ corpus callosum (hypoplasia, short corpus callosum and verticalized splenium), 2/ septum pellucidum (cavum septum pellucidum or cavum vergae), 3/ ventricles (ventriculomegaly), 4/ cerebral cortex (cortical dysplasia), 5/ cerebellum (hypoplasia), and 6/ extra-axial CSF spaces (enlargement). In our patient population, dysplasia involving the cerebellum and vermis have been identified, a finding that has not yet been described in the literature. MRI allows detection of multiple minor morphological anomalies. Most have classically been considered as normal variants but they may in fact be markers of cerebral dysgenesis and are currently the only anomaly detected in the work-up of patients with mental retardation. Their role in the pathogenesis of mental retardation is under evaluation.

Unexplained mental retardation: is brain MRI useful?

BACKGROUND

Mental retardation (MR), defined as an IQ below 70, is a frequent cause of consultation in paediatrics.

OBJECTIVE

To evaluate the yield of brain MRI in the diagnostic work-up of unexplained MR in children.

PATIENTS AND METHODS

The MRI features and clinical data of 100 patients (age 1-18 years) affected with non-progressive MR of unknown origin were compared to an age-matched control group (n=100). Two radiologists conducted an independent review of the MRI scans.

RESULTS

Univariate and multivariate analyses showed a higher incidence of brain anomalies in the MR group than in the control group (53 vs 17, OR=5.7 [2.9-11.1]), for signal abnormalities within the periventricular white matter (OR=20.3 [2.6-155.3]), lateral ventricular dilatation (OR=15.6 [2.0-124]), mild corpus callosum abnormalities (shortness, atrophy) (OR=6.8 [1.8-25.6]) and subtle cerebellar abnormalities, including fissure enlargement (OR=5.2 [1.1-26.2]). The diagnostic value of MRI abnormalities was considered good in 5% of patients (Alexander disease n=1, diffuse cortical malformation n=1, leukomalacia n=1, vermian agenesis n=1, commissural agenesis n=1), and weak in 48% of patients, in whom non-specific abnormalities did not lead to a diagnosis. Some clinical features resulted in a significantly higher percentage of abnormal MRI scans: abnormal neurological examination (82% vs 47%, P=0.008), abnormal skull circumference (66% vs 49%, P=0.04). Motor delay was associated with cerebellar abnormalities (P=0.01).

CONCLUSIONS

This study confirms the weak diagnostic yield of MRI in mentally retarded children. The use of a control group has enabled us to identify the neuroimaging markers frequently associated with MR. Subgrouping patients according to neuroimaging markers and clinical signs should help identify those who would benefit from molecular studies.

Profile of pediatric hemiparesis

Our objective was to determine the clinical spectrum of pediatric hemiparesis by identifying the relative frequency of various diagnoses and comorbid conditions seen in these children. Case records of all patients with hemiparesis in a single practice over an 11-year period were reviewed with reference to clinical features, etiologic determination, and comorbid conditions. Ninety-two children were identified: 73 (79.3%) had a congenital hemiparesis and 19 (20.7%) had an acquired hemiparesis. An abnormal perinatal history (P = .003), prematurity (P = .016), and younger age at onset of symptoms (P < .001) were associated with a congenital hemiparesis. The overall etiologic yield was 83.7% (82.2% in the congenital and 89.5% in the acquired). The top four etiologic entities were cerebrovascular ischemia (40.2%), periventricular leukomalacia (18.5%), intracranial hemorrhage (16.3%), and cerebral dysgenesis (13%). Factors predictive of establishing an underlying etiology included birth prior to 34 weeks' gestation (P = .034), global developmental delay (P = .048), epilepsy (P = .024), and having appropriate imaging modalities (P = .001). Half of these children had a concurrent global developmental delay, associated epilepsy (odds ratio 3.67; 95% confidence interval 1.40-9.72), and prematurity (odds ratio 5.41; 95% confidence interval 1.56-18.80). A third of these children developed epilepsy. Multivariate predictive factors for epilepsy included global developmental delay (odds ratio 4.20; 95% confidence interval 1.44-12.27), cerebrovascular ischemia (odds ratio 5.10; 95% confidence interval 1.76-14.77), and term birth (odds ratio 3.87; 95% confidence interval 1.20-12.56). The majority of children with hemiparesis have a congenital etiology. The diagnostic yield is higher than previously reported; however, specific underlying etiologies need to be better determined. Comorbid conditions of global developmental delay and epilepsy have a high prevalence in this population, contributing to overall morbidity.

Diagnostic investigations in individuals with mental retardation: a systematic literature review of their usefulness

There are no guidelines available for diagnostic studies in patients with mental retardation (MR) established in an evidence-based manner. Here we report such study, based on information from original studies on the results with respect to detected significant anomalies (yield) of six major diagnostic investigations, and evaluate whether the yield differs depending on setting, MR severity, and gender. Results for cytogenetic studies showed the mean yield of chromosome aberrations in classical cytogenetics to be 9.5% (variation: 5.4% in school populations to 13.3% in institute populations; 4.1% in borderline-mild MR to 13.3% in moderate-profound MR; more frequent structural anomalies in females). The median yield of subtelomeric studies was 4.4% (also showing female predominance). For fragile X screening, yields were 5.4% (cytogenetic studies) and 2.0% (molecular studies) (higher yield in moderate-profound MR; checklist use useful). In metabolic investigations, the mean yield of all studies was 1.0% (results depending on neonatal screening programmes; in individual populations higher yield for specific metabolic disorders). Studies on neurological examination all showed a high yield (mean 42.9%; irrespective of setting, degree of MR, and gender). The yield of neuroimaging studies for abnormalities was 30.0% (higher yield if performed on an indicated basis) and the yield for finding a diagnosis based on neuroradiological studies only was 1.3% (no data available on value of negative findings). A very high yield was found for dysmorphologic examination (variation 39-81%). The data from this review allow conclusions for most types of diagnostic investigations in MR patients. Recommendations for further studies are provided.

Supratentorial functional disturbances in two children with cerebellar cortical dysplasia

When evaluating children with mental retardation, subtle cerebral and cerebellar morphologic anomalies are often noted at Magnetic Resonance Imaging (MRI). Some, such as cerebellar cortical dysplasia (CCD), have been considered as subtle markers of cerebral dysgenesis. Their functional significance and their effect on brain function, remain unknown. To study supratentorial functional disturbances related to CCD we performed Positron-Emission-Tomography (PET) studies in two children with isolated CCD, in order to investigate the degree of involvement of supratentorial structures. One had developmental delay, motor disturbances and ataxia, and the other one only had mental retardation. PET studies revealed hypoperfusion and hypometabolism within the vermis, thalamus and the right striatum in one case, and hypometabolism in the basal ganglia and cerebellar deep grey nuclei in the other case. Our results could lead to a hypothesis explaining motor disturbances as well as cognitive impairment, and could suggest a pathological functional significance of CCD. Nevertheless, the relationship between these findings and mental retardation needs further investigation.

Agenesis of the corpus callosum is associated with feeding difficulties

Our objective was to characterize the common occurrence of feeding and swallowing disorders noticed by our speech therapy department among patients with agenesis of the corpus callosum. All patients with suspected or presumed agenesis of the corpus callosum undergoing therapy for feeding and/or swallowing disorders, including oral and/or pharyngeal dysphagia and oral-sensory disorder, were identified. Their brain magnetic resonance imaging (MRI) studies and charts were reviewed in detail. Seven patients with striking oral-motor and oral-sensory disorder met the criteria for agenesis of the corpus callosum. Particular difficulties noted include oral-sensory defensiveness in five of these seven patients, oral dysphagia/weakness in all seven patients, and pharyngeal dysphagia with risk of aspiration in three of these seven patients. The oral-motor weakness observed in all of the patients affected the strength and coordination necessary for functional oral-phase swallowing. We conclude that feeding and swallowing disorders are significant in children with agenesis of the corpus callosum. Although the pathophysiologic mechanism is not known, recognition of this phenomenon is important because early detection and intervention can facilitate functional feeding and swallowing patterns earlier in these patients, therefore avoiding the adverse and more severe disorders that can arise when dysphagias and/or oral-sensory disorder persist over extended periods of time.

Neuroimaging in mental retardation

OBJECTIVE

To determine the diagnostic yield of neuroimaging in a cohort of children with mental retardation of unknown origin.

METHODS

Neuroimaging was performed in a total of 47 patients with developmental delay/mental retardation, where no etiologic diagnosis could be made following clinical examination and preliminary investigations.

RESULTS

Thirty (63.82%) children had abnormal neuroimaging findings of which 19 (42.42%) were specific abnormalities useful in arriving at etiological diagnosis. Positive outcome of neuroimaging increased with the severity of mental retardation and in presence of microcephaly and neurologic deficits other than mental retardation.

CONCLUSION

Neuroimaging should be the standard clinical practice for a child with global developmental delay where no cause is apparent after examination and relevant investigations.

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

Mental Retardation (MR) is a problem encountered in almost all paediatric clinical settings. The assessment of a child with MR is a common diagnostic and management dilemma for paediatricians. The field of MR research is currently in a state of flux regarding not just our understanding of the condition, but also in the language and the processes we use in naming, defining and describing MR. This article will provide a better understanding and a rational approach toward MR. Prevalence rates for MR are variable in the literature and may be attributable to the variation in major classification systems and the diversity in study operation definitions and methodologies. Etiologies of MR are diverse and include many different influences. MR most often presents during infancy or preschool years as developmental delay. There is no universally accepted approach to the etiological work-up of mental retardation. The number of medical conditions associated with MR that are completely treatable by medical means remains small. The paediatrician plays a key role establishing short and long term treatment goals, as well as providing support to families who have children with MR.

MRI in children with mental retardation

BACKGROUND

In mental retardation (MR) an aetiological diagnosis is not always obtained despite a detailed history, physical examination and metabolic or genetic investigations. In some of these patients, MRI is recommended and may identify subtle abnormal brain findings.

OBJECTIVE

We reviewed the cerebral MRI of children with non-specific mental retardation in an attempt to establish a neuroanatomical picture of this disorder.

MATERIALS AND METHODS

Thirty children with non-specific MR were selected to undergo cerebral MRI. The examination included supratentorial axial slices, mid-sagittal images and posterior fossa coronal images. Brain malformations, midline and cerebellar abnormalities were studied.

RESULTS

In 27 of 30 patients, the neuroimaging evaluation revealed a relatively high incidence of cerebral and posterior fossa abnormalities. The most frequent were: dysplasia of the corpus callosum (46%; hypoplasia, short corpus callosum and vertical splenium), partially opened septum pellucidum and/or cavum vergae (33%), ventriculomegaly (33%), cerebral cortical dysplasia (23%), subarachnoid space enlargement (16.6%), vermian hypoplasia (33%), cerebellar and/or vermian disorganised folia (20%), and subarachnoid spaces enlargement in the posterior fossa (20%). Other anomalies were: enlarged Virchow-Robin spaces (10%), white matter anomalies (10%) and cerebellar or vermian atrophy.

CONCLUSIONS

MRI has shown a high incidence of subtle cerebral abnormalities and unexpected minor forms of cerebellar cortical dysplasia. Even if most of these abnormalities are considered as subtle markers of brain dysgenesis, their role in the pathogenesis of mental retardation needs further investigation.

Advances in molecular cytogenetics for the evaluation of mental retardation

Recent years have witnessed rapid advances in molecular cytogenetics and its impact in studying mental retardation (MR). We review new molecular cytogenetic methods, including interphase fluorescence in situ hyrbridization (FISH), comparative genomic hybridization (CGH), multicolor karyotyping, telomere FISH, primed in situ labeling (PRINS), genotyping, microdissection, and microarray for the evaluation of MR. These new methods are very useful in two major aspects: further characterization of chromosome abnormalities as detected with routine banding analysis, including additions, duplications, deletions, translocations, markers, or complex aberrations; and screening for "hidden" chromosome aberrations in patients with an apparently normal karyotype. These new methods have great diagnostic potential in prenatal, postnatal, and preimplantational settings. Although powerful, at this point, they are primarily research tools in nature. It is essential that these new methods be used in conjunction with standard methods in order to maximize obtainable information for better management of patients with MR.

Mental retardation

Mental retardation (MR) occurs in 2-3% of the general population. Prevalence of milder MR is seven to ten times more than severe MR. Cause of severe MR can be determined in 60-70% of cases, as compared to mild MR where 35-55% remain idiopathic. The diagnostic process is aided considerably if the timing of a developmental insult can be determined: prenatal, periatal, postnatal (not mutually exclusive). History plays a pivotal role in approaching a diagnosis. After clinical evaluation one should be able to assess whether the disorder is static or progressive; approximate developmental quotient; possible timing of insult and possible underlying genetic etiology. Investigations should be based on history and physical examination. The important category of tests include: thyroid function tests, cytogenetic studies, metabolic work-up, fragile-X screening, radiological investigations, electrophysiological studies and specific tests according to the suspected diagnosis. Having an etiological explanation aids in the development of a specific treatment plan; helps families understand prognosis and recurrence risk and on the community level assists in the development of preventive strategies.

Disabilities and trends over time in a French county, 1980-91

AIM

To describe trends over time and types of disability for children born in a French county from 1980 to 1991.

METHODS

Data were collected from medical records of a morbidity register; disabled children with at least one severe deficiency have been included. Prevalence rates are given per 1000 resident children, over four three-year periods.

RESULTS

Overall, 7.73 per 1000 children (that is, 1360 children), had a severe childhood disability, and the prevalence rate had increased significantly since 1980. This increase was mainly owing to an increase in cerebral palsy and psychiatric disorder prevalence rates.

CONCLUSION

Future research aimed to explain these trends over time can be based on such data. The present knowledge is useful for planning purposes.

Klinefelter syndrome is a common cause for mental retardation of unknown etiology among prepubertal males

Klinefelter syndrome (KS) has not typically been associated with mental retardation (MR), however, in recent years a growing body of evidence suggested that KS boys often experience language deficits and academic difficulties. In this study, we screened DNA samples from 1205 patients originally referred for fragile X syndrome (FRAX) testing, because of MR of unknown etiology and detected 8 KS patients. A similar number of males in the same age group were found to have FRAX; 3 of them had a family history of FRAX. Based on these findings, KS might be the most common cause of MR of unknown etiology among prepubertal males. Because of the significant benefits of early recognition and treatment of KS, we emphasize the importance of cytogenetic testing of all prepubertal males with cognitive impairment even without dysmorphic features.

Profile of referrals for early childhood developmental delay to ambulatory subspecialty clinics

The objective of this study was to determine the profile and pattern of referral to subspecialty clinics of young children with suspected developmental delay together with the factors prompting their referral. All children under 5 years of age referred to either developmental pediatrics or pediatric neurology clinics at a single tertiary hospital over an 18-month period were prospectively identified. Standardized demographic and referral information were collected at intake, final developmental delay subtype diagnosed was identified, and referring physicians were surveyed regarding factors prompting referral. A total of 224 children met study criteria. There was a marked male preponderance (166/224), especially among those with either cognitive or language delay. Two delay subtypes, global developmental delay and developmental language disorder, accounted for two thirds of the diagnoses made. For slightly more than one third of the children (75/224), the delay subtype diagnosed following specialty evaluation was different from that initially suspected by the referring physician. A mean delay of 15.5 months was observed for the cohort as a whole between initial parental concern and specialty assessment. For referring physicians, the major factor prompting referral was the severity of the observed delay. The most important aspects of the specialty evaluation according to referral sources were the identification of a possible etiology and confirmation of delay. A profile of referrals and the rationale thereof for a cohort of children with suspected developmental delay is presented that, although locale specific, has implications for service provision and training.

Etiologic determination of childhood developmental delay

To determine the etiologic yield in young children with developmental delay referred to sub-specialty clinics for evaluation. Over an 18-month period, all children less than 5 years of age referred to the ambulatory pediatric neurology or developmental pediatrics clinics of the Montreal Children's Hospital for initial evaluation of a suspected developmental delay were enrolled. Features evident on history or physical examination were determined at intake as were the laboratory tests (and their rationale) requested by the evaluating physicians. Six months post initial assessment, detailed chart review was undertaken to determine if an etiology was found and the basis for such a determination. Bivariate and multivariate logistic regression was used to test for associations between factors present at intake and successful ascertainment of an underlying etiology. Two hundred and twenty-four children met study criteria. Etiologic yield varied across childhood developmental delay subtypes, and was 44/80 for global developmental delay [GDD] (55%), 13/22 for motor delay [MD] (59.1%), 3/72 for developmental language disorders [DLD] (4.2%), and 1/50 for autistic spectrum disorders [ASD] (2%). For GDD, the presence of historical features or findings on physical examination was associated with greater likelihood for successful etiologic determination with the following items significant in multiple logistic regression analysis; microcephaly, antenatal toxin exposure, focal findings. For MD, physical findings or the co-existence of a cerebral palsy symptom complex predicted a successful search for etiology. For both groups, the severity of the delay did not predict etiologic yield. For both groups, a small number of etiologic categories accounted for the majority of diagnoses made. Etiologic yield in childhood developmental delay is largely dependent on the specific developmental delay subtype. Paradigms for systematic evaluation of this common child health problem can be suggested, however they await validation.

Etiologic yield of autistic spectrum disorders: a prospective study

At present, the etiologic yield in community-derived samples of young children with an autistic spectrum disorder is not known. To address this question, all young children (under 5 years of age) referred for an initial assessment to ambulatory pediatric neurology or developmental pediatric clinics at a tertiary university center over an 18-month period for a suspected developmental delay were prospectively identified. Specific diagnostic testing was left to the discretion of the evaluating physician. In all, 50 children with an autistic spectrum disorder were assessed. Detailed history or physical examination was informative with respect to suggesting the possibility of an underlying etiology in a minority (10/50,20%). Genetic studies (FMR-1, karyotype), electroencephalography (EEG), and neuroimaging were carried out in a majority (42/50, 34/50, and 33/50, respectively) of the children, for the most part on a screening rather than an indicated basis (31/42, 34/34, and 28/33, respectively). Etiologic yield was low (1/50, 2%), with only a single child identified with a possible Landau-Kleffner variant on sleep EEG tracing. The results suggest an evaluation paradigm with reference to etiologic determination for young children with autistic spectrum disorder that does not presently justify metabolic or neuroimaging on a screening basis. Recurrence risk and treatment implications, however, suggest that strong consideration be given to genetic (FMR-1, karyotype) testing and EEG study despite a relatively low yield.