Risk and Resilience Variants in the Retinoic Acid Metabolic and Developmental Pathways Associated with Risk of FASD Outcomes

Fetal Alcohol Spectrum Disorder (FASD) is a common neurodevelopmental disorder that affects an estimated 2-5% of North Americans. FASD is induced by prenatal alcohol exposure (PAE) during pregnancy and while there is a clear genetic contribution, few genetic factors are currently identified or understood. In this study, using a candidate gene approach, we performed a genetic variant analysis of retinoic acid (RA) metabolic and developmental signaling pathway genes on whole exome sequencing data of 23 FASD-diagnosed individuals. We found risk and resilience alleles in ADH and ALDH genes known to normally be involved in alcohol detoxification at the expense of RA production, causing RA deficiency, following PAE. Risk and resilience variants were also identified in RA-regulated developmental pathway genes, especially in SHH and WNT pathways. Notably, we also identified significant variants in the causative genes of rare neurodevelopmental disorders sharing comorbidities with FASD, including STRA6 (Matthew-Wood), SOX9 (Campomelic Dysplasia), FDG1 (Aarskog), and 22q11.2 deletion syndrome (TBX1). Although this is a small exploratory study, the findings support PAE-induced RA deficiency as a major etiology underlying FASD and suggest risk and resilience variants may be suitable biomarkers to determine the risk of FASD outcomes following PAE.

Molecular characterization of 13 patients with PIK3CA-related overgrowth spectrum using a targeted deep sequencing approach

Activating variants in the PIK3CA gene cause a heterogeneous spectrum of disorders that involve congenital or early-onset segmental/focal overgrowth, now referred to as PIK3CA-related overgrowth spectrum (PROS). Historically, the clinical diagnoses of patients with PROS included a range of distinct syndromes, including CLOVES syndrome, dysplastic megalencephaly, hemimegalencephaly, focal cortical dysplasia, Klippel-Trenaunay syndrome, CLAPO syndrome, fibroadipose hyperplasia or overgrowth, hemihyperplasia multiple lipomatosis, and megalencephaly capillary malformation-polymicrogyria (MCAP) syndrome. MCAP is a sporadic overgrowth disorder that exhibits core features of progressive megalencephaly, vascular malformations, distal limb malformations, cortical brain malformations, and connective tissue dysplasia. In 2012, our research group contributed to the identification of predominantly mosaic, gain-of-function variants in PIK3CA as an underlying genetic cause of the syndrome. Mosaic variants are technically more difficult to detect and require implementation of more sensitive sequencing technologies and less stringent variant calling algorithms. In this study, we demonstrated the utility of deep sequencing using the Illumina TruSight Oncology 500 (TSO500) sequencing panel in identifying variants with low allele fractions in a series of patients with PROS and suspected mosaicism: pathogenic, mosaic PIK3CA variants were identified in all 13 individuals, including 6 positive controls. This study highlights the importance of screening for low-level mosaic variants in PROS patients. The use of targeted panels with deep sequencing in clinical genetic testing laboratories would improve diagnostic yield and accuracy within this patient population.

Eye movement defects in KO zebrafish reveals SRPK3 as a causative gene for an X-linked intellectual disability

Intellectual disability (ID) is a common neurodevelopmental disorder characterized by significantly impaired intellectual and adaptive functioning. X-linked ID (XLID) disorders, caused by defects in genes on the X chromosome, affect 1.7 out of 1,000 males. Employing exome sequencing, we identified three missense mutations (c.475C>G; p.H159D, c.1373C>A; p.T458N, and c.1585G>A; p.E529K) in the SRPK3 gene in seven XLID patients from three independent families. Clinical features common to the patients are intellectual disability, agenesis of the corpus callosum, abnormal smooth pursuit eye movement, and ataxia. SRPK proteins are known to be involved in mRNA processing and, recently, synaptic vesicle and neurotransmitter release. In order to validate SRPK3 as a novel XLID gene, we established a knockout (KO) model of the SRPK3 orthologue in zebrafish. In day 5 of larval stage, KO zebrafish showed significant defects in spontaneous eye movement and swim bladder inflation. In adult KO zebrafish, we found agenesis of cerebellar structures and impairments in social interaction. These results suggest an important role of SRPK3 in eye movements, which might reflect learning problems, intellectual disability, and other psychiatric disorders.

Alternative genomic diagnoses for individuals with a clinical diagnosis of Dubowitz syndrome

Dubowitz syndrome (DubS) is considered a recognizable syndrome characterized by a distinctive facial appearance and deficits in growth and development. There have been over 200 individuals reported with Dubowitz or a "Dubowitz-like" condition, although no single gene has been implicated as responsible for its cause. We have performed exome (ES) or genome sequencing (GS) for 31 individuals clinically diagnosed with DubS. After genome-wide sequencing, rare variant filtering and computational and Mendelian genomic analyses, a presumptive molecular diagnosis was made in 13/27 (48%) families. The molecular diagnoses included biallelic variants in SKIV2L, SLC35C1, BRCA1, NSUN2; de novo variants in ARID1B, ARID1A, CREBBP, POGZ, TAF1, HDAC8, and copy-number variation at1p36.11(ARID1A), 8q22.2(VPS13B), Xp22, and Xq13(HDAC8). Variants of unknown significance in known disease genes, and also in genes of uncertain significance, were observed in 7/27 (26%) additional families. Only one gene, HDAC8, could explain the phenotype in more than one family (N = 2). All but two of the genomic diagnoses were for genes discovered, or for conditions recognized, since the introduction of next-generation sequencing. Overall, the DubS-like clinical phenotype is associated with extensive locus heterogeneity and the molecular diagnoses made are for emerging clinical conditions sharing characteristic features that overlap the DubS phenotype.

Profile of Mothers of Children with Fetal Alcohol Spectrum Disorder: A Population-Based Study in Canada

Objective: To compare the characteristics of mothers of children with Fetal Alcohol Spectrum Disorder (FASD) with mothers of typically developing control children. Methods: The study utilized a cross-sectional, observational design, using active case ascertainment. Biological mothers were interviewed using a standardized retrospective questionnaire to collect data on demographics, living environment, pregnancy history, nutrition, alcohol and other drug use prior to and following pregnancy recognition. Results: A total of 173 mothers were interviewed. Of these, 19 had a child who was diagnosed with FASD, five had a child who had received a deferred FASD diagnosis, and 37 had children who were selected into the control group as typically developing children. The remaining 112 mothers had children who did not meet diagnostic criteria for FASD. The mothers of children with FASD did not differ significantly from mothers of the control group children with respect to age, ethnicity, marital status, and employment status at the time of pregnancy. However, mothers of children with FASD had lower levels of education (p < 0.01) and were more likely to have received financial support (p < 0.05) at the time of pregnancy, to have smoked tobacco (p < 0.001), and to have used marijuana or hashish (p < 0.01) prior to pregnancy recognition, compared with mothers of control children. All mothers of children with FASD reported alcohol consumption prior to pregnancy recognition; however, only 10.5% reported alcohol consumption following pregnancy recognition. None of the mothers interviewed reported any drug use following pregnancy recognition. Conclusions: Population-based preventive interventions, including repeated screening, monitoring, and education regarding the effects of alcohol use, as well as other substances, before and during pregnancy, are needed to eliminate risk for FASD and other negative consequences on child and maternal health.

Population-based prevalence of fetal alcohol spectrum disorder in Canada

Background

Fetal alcohol spectrum disorder (FASD) is one of the most disabling potential outcomes of prenatal alcohol exposure. The population-based prevalence of FASD among the general population of Canada was unknown. The objective of this study was to determine the population-based prevalence of FASD among elementary school students, aged 7 to 9 years, in the Greater Toronto Area (GTA) in Ontario, Canada.

Methods

This screening study used a cross-sectional, observational design utilizing active case ascertainment, along with retrospective collection of prenatal alcohol exposure information. Data collection involved two phases. Phase I consisted of taking growth measurements, a dysmorphology examination, and obtaining a history of behavioral and/or learning problems. Phase II consisted of a neurodevelopmental assessment, maternal interview, and behavioral observations/ratings by parents/guardians. Final diagnostic screening conclusions were made by consensus by a team of experienced multidisciplinary experts during case conferences, using the 2005 Canadian guidelines for FASD diagnosis. The prevalence of FASD was estimated, taking into consideration the selection rate, which was used to account for students who dropped out or were lost to follow-up during each phase. Monte Carlo simulations were employed to derive the confidence interval (CI) for the point estimates.

Results

A total of 2555 students participated. A total of 21 cases of suspected FASD were identified. The prevalence of FASD was estimated to be 18.1 per 1000, or about 1.8%. Using a less conservative approach (sensitivity analysis), the prevalence of FASD was estimated to be 29.3 per 1000, or about 2.9%. Therefore, the population-based prevalence of FASD is likely to range between 2 and 3% among elementary school students in the GTA in Ontario, Canada.

Conclusions

This study provides the first population-based estimate of the prevalence of FASD in Canada. The estimate is approximately double or possibly even triple previous crude estimates. FASD prevalence exceeds that of other common birth defects such as Down’s syndrome, spina bifida, trisomy 18, as well as autism spectrum disorder in Canada. More effective prevention strategies targeting alcohol use during pregnancy, surveillance of FASD, and timely interventions and support to individuals with FASD and their families are urgently needed.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7213-3) contains supplementary material, which is available to authorized users.

Kabuki syndrome: international consensus diagnostic criteria

BACKGROUND

Kabuki syndrome (KS) is a clinically recognisable syndrome in which 70% of patients have a pathogenic variant in KMT2D or KDM6A. Understanding the function of these genes opens the door to targeted therapies. The purpose of this report is to propose diagnostic criteria for KS, particularly when molecular genetic testing is equivocal.

METHODS

An international group of experts created consensus diagnostic criteria for KS. Systematic PubMed searches returned 70 peer-reviewed publications in which at least one individual with molecularly confirmed KS was reported. The clinical features of individuals with known mutations were reviewed.

RESULTS

The authors propose that a definitive diagnosis can be made in an individual of any age with a history of infantile hypotonia, developmental delay and/or intellectual disability, and one or both of the following major criteria: (1) a pathogenic or likely pathogenic variant in KMT2D or KDM6A; and (2) typical dysmorphic features (defined below) at some point of life. Typical dysmorphic features include long palpebral fissures with eversion of the lateral third of the lower eyelid and two or more of the following: (1) arched and broad eyebrows with the lateral third displaying notching or sparseness; (2) short columella with depressed nasal tip; (3) large, prominent or cupped ears; and (4) persistent fingertip pads. Further criteria for a probable and possible diagnosis, including a table of suggestive clinical features, are presented.

CONCLUSION

As targeted therapies for KS are being developed, it is important to be able to make the correct diagnosis, either with or without molecular genetic confirmation.

Copy number variation in fetal alcohol spectrum disorder

Fetal alcohol spectrum disorder (FASD) is characterized by a combination of neurological, developmental, and congenital defects that may occur as a consequence of prenatal alcohol exposure. Earlier reports showed that large chromosomal anomalies may link to FASD. Here, we examined the prevalence and types of copy number variations (CNVs) in FASD cases previously diagnosed by a multidisciplinary FASD team in sites across Canada. We genotyped 95 children with FASD and 87 age-matched, typically developing controls on the Illumina Human Omni2.5 SNP (single nucleotide polymorphisms) array platform. We compared their CNVs with those of 10 851 population controls to identify rare CNVs (<0.1% frequency), which may include large unbalanced chromosomal abnormalities, that might be relevant to FASD. In 12/95 (13%) of the FASD cases, rare CNVs were found that impact potentially clinically relevant developmental genes, including the CACNA1H involved in epilepsy and autism, the 3q29 deletion disorder, and others. Our results show that a subset of children diagnosed with FASD have chromosomal deletions and duplications that may co-occur or explain the neurodevelopmental impairments in a diagnosed cohort of FASD individuals. Children suspected to have FASD with or without sentinel facial features of fetal alcohol syndrome and neurodevelopmental delays should potentially be evaluated by a clinical geneticist and possibly have genetic investigations as appropriate to exclude other etiologies.

DNA methylation as a predictor of fetal alcohol spectrum disorder

Background

Fetal alcohol spectrum disorder (FASD) is a developmental disorder that manifests through a range of cognitive, adaptive, physiological, and neurobiological deficits resulting from prenatal alcohol exposure. Although the North American prevalence is currently estimated at 2-5%, FASD has proven difficult to identify in the absence of the overt physical features characteristic of fetal alcohol syndrome. As interventions may have the greatest impact at an early age, accurate biomarkers are needed to identify children at risk for FASD. Building on our previous work identifying distinct DNA methylation patterns in children and adolescents with FASD, we have attempted to validate these associations in a different clinical cohort and to use our DNA methylation signature to develop a possible epigenetic predictor of FASD.

Methods

Genome-wide DNA methylation patterns were analyzed using the Illumina HumanMethylation450 array in the buccal epithelial cells of a cohort of 48 individuals aged 3.5-18 (24 FASD cases, 24 controls). The DNA methylation predictor of FASD was built using a stochastic gradient boosting model on our previously published dataset FASD cases and controls (GSE80261). The predictor was tested on the current dataset and an independent dataset of 48 autism spectrum disorder cases and 48 controls (GSE50759).

Results

We validated findings from our previous study that identified a DNA methylation signature of FASD, replicating the altered DNA methylation levels of 161/648 CpGs in this independent cohort, which may represent a robust signature of FASD in the epigenome. We also generated a predictive model of FASD using machine learning in a subset of our previously published cohort of 179 samples (83 FASD cases, 96 controls), which was tested in this novel cohort of 48 samples and resulted in a moderately accurate predictor of FASD status. Upon testing the algorithm in an independent cohort of individuals with autism spectrum disorder, we did not detect any bias towards autism, sex, age, or ethnicity.

Conclusion

These findings further support the association of FASD with distinct DNA methylation patterns, while providing a possible entry point towards the development of epigenetic biomarkers of FASD.

The Manitoba Youth Justice Program: empowering and supporting youth with FASD in conflict with the law

Fetal alcohol spectrum disorder (FASD) describes a constellation of physical, cognitive, neurologic, and behavioral impairments resulting from prenatal exposure to alcohol. FASD is recognized as being one of the most common causes of preventable brain injury in children. There had long been concerns that some youth in conflict with the law may be affected with FASD given repetitive patterns of offending and apparent lack of understanding of the consequences of their actions. In 2004, funding was received from Justice Canada for a pilot project with a cross-departmental steering committee working together to determine a best way of working across systems to provide FASD assessments to these youth. It was recognized that provision of timely FASD assessments would allow the court to provide more meaningful sentences taking into account the youth's strengths and challenges and enhance the changes of decreased recidivism and increased changes of rehabilitation. This paper describes the basic science around FASD and its diagnosis, provides a history of the FASD Youth Justice Program, and reports on legal issues, structure, statistics, accomplishments, and ongoing future challenges.

Human Brain Abnormalities Associated With Prenatal Alcohol Exposure and Fetal Alcohol Spectrum Disorder

Fetal alcohol spectrum disorder (FASD) is a common neurodevelopmental problem, but neuropathologic descriptions are rare and focused on the extreme abnormalities. We conducted a retrospective survey (1980–2016) of autopsies on 174 individuals with prenatal alcohol exposure or an FASD diagnosis. Epidemiologic details and neuropathologic findings were categorized into 5 age groups. Alcohol exposure was difficult to quantify. When documented, almost all mothers smoked tobacco, many abused other substances, and prenatal care was poor or nonexistent. Placental abnormalities were common (68%) in fetal cases. We identified micrencephaly (brain weight <5th percentile) in 31, neural tube defects in 5, isolated hydrocephalus in 6, corpus callosum defects in 6 (including some with complex anomalies), probable prenatal ischemic lesions in 5 (excluding complications of prematurity), minor subarachnoid heterotopias in 4, holoprosencephaly in 1, lissencephaly in 1, and cardiac anomalies in 26 cases. The brain abnormalities associated with prenatal alcohol exposure are varied; cause–effect relationships cannot be determined. FASD is likely not a monotoxic disorder. The animal experimental literature, which emphasizes controlled exposure to ethanol alone, is therefore inadequate. Prevention must be the main societal goal, however, a clear understanding of the neuropathology is necessary for provision of care to individuals already affected.

Diagnosis of fetal alcohol spectrum disorder: current practices and future considerations

This paper discusses the current state of knowledge and practice for diagnosing fetal alcohol spectrum disorder (FASD). The strengths and challenges of different models of diagnosis are compared. Some models require a team approach for evaluation, while other approaches assume that a clinician in his or her office provides a diagnosis based on a review of the patient's medical and social history, behaviour, and physical examination. The author reviews the emergence of new information from recent advances in genetics, imaging, and electrophysiology that has the potential to lead to changes in practice and improved reliability of an FASD diagnosis.

Overview of the Genetic Basis and Epigenetic Mechanisms that Contribute to FASD Pathobiology

Prenatal alcohol (ethanol) exposure (PAE) is the underlying cause for a variety of birth defects and neurodevelopmental deficits referred to as "Fetal Alcohol Spectrum Disorders (FASD)". The more visible phenotypes caused by PAE include growth retardation, and characteristic craniofacial abnormalities associated with functional and structural damage to the central nervous system. Ethanol is a teratogenic agent itself; but it can also alter gene expression. These changes may contribute to the spectrum of effects and different phenotypes that are dependent on alcohol metabolism, as well as the timing and duration of alcohol exposure. Evidence from both human patients and animal models show that genetic factors and epigenetic mechanisms such as DNA methylation, histone post-translational modifications and noncoding RNAs, contribute to the gene expression changes caused by ethanol. Not all embryos that are exposed to alcohol during development exhibit FASD symptoms after birth. FASD patients may present severe birth defects, while others are normal in physical appearance but present a variety of cognitive and behavioral difficulties. It has been hypothesized that maternal and paternal genetic factors may contribute to the sensitivity, resistance or vulnerability of the fetus to alcohol. Moreover, the epigenome is highly sensitive to a multitude of environmental insults including PAE. Studies also show 'transgenerational' effects of alcohol. In such cases, maternal or paternal preconception alcohol consumption could lead to FASD-like phenotypes in the newborn. Thus, the phenotypes in FASD can be modified by interplay between maternal/paternal genetic factors and epigenetic mechanisms. This current review summarizes the contribution of genetic and epigenetic mechanisms in FASD pathobiology, and how this information could be utilized for prevention, early diagnosis and potentially treatment of the affected individuals.

DNA methylation signature of human fetal alcohol spectrum disorder

Background

Prenatal alcohol exposure is the leading preventable cause of behavioral and cognitive deficits, which may affect between 2 and 5 % of children in North America. While the underlying mechanisms of alcohol’s effects on development remain relatively unknown, emerging evidence implicates epigenetic mechanisms in mediating the range of symptoms observed in children with fetal alcohol spectrum disorder (FASD). Thus, we investigated the effects of prenatal alcohol exposure on genome-wide DNA methylation in the NeuroDevNet FASD cohort, the largest cohort of human FASD samples to date.

Methods

Genome-wide DNA methylation patterns of buccal epithelial cells (BECs) were analyzed using the Illumina HumanMethylation450 array in a Canadian cohort of 206 children (110 FASD and 96 controls). Genotyping was performed in parallel using the Infinium HumanOmni2.5-Quad v1.0 BeadChip.

Results

After correcting for the effects of genetic background, we found 658 significantly differentially methylated sites between FASD cases and controls, with 41 displaying differences in percent methylation change >5 %. Furthermore, 101 differentially methylated regions containing two or more CpGs were also identified, overlapping with 95 different genes. The majority of differentially methylated genes were highly expressed at the level of mRNA in brain samples from the Allen Brain Atlas, and independent DNA methylation data from cortical brain samples showed high correlations with BEC DNA methylation patterns. Finally, overrepresentation analysis of genes with up-methylated CpGs revealed a significant enrichment for neurodevelopmental processes and diseases, such as anxiety, epilepsy, and autism spectrum disorders.

Conclusions

These findings suggested that prenatal alcohol exposure is associated with distinct DNA methylation patterns in children and adolescents, raising the possibility of an epigenetic biomarker of FASD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13072-016-0074-4) contains supplementary material, which is available to authorized users.

Comorbidity of fetal alcohol spectrum disorder: a systematic review and meta-analysis

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is related to many comorbidities because of the permanent effects of prenatal alcohol exposure on the fetus. We aimed to identify the comorbid conditions that co-occur in individuals with FASD and estimate the pooled prevalence of comorbid conditions occurring in individuals with fetal alcohol syndrome (FAS).

METHODS

We did a systematic literature search of studies reporting on the comorbidity and cause of death in individuals with FASD using multiple electronic bibliographic databases, searching for studies published up to July, 2012. We included original research published in a peer-reviewed journal in the English language. We used the following criteria for determining study quality: use of an established FASD diagnostic guideline, study setting, method of data collection, and sample size. All comorbid disease conditions were coded according to the International Classification of Diseases, tenth revision (ICD-10). To estimate the pooled prevalence of comorbid conditions found to co-occur in individuals with FAS, we did meta-analyses assuming a random-effects model.

FINDINGS

Of 5068 studies found, 127 met eligibility criteria for data extraction. From those studies, we identified 428 comorbid conditions co-occurring in individuals with FASD, spanning across 18 of 22 chapters of the ICD-10. The most prevalent disease conditions were within the sections of congenital malformations, deformities, and chromosomal abnormalities, and mental and behavioural disorders. 33 studies reported data for frequency in a total of 1728 participants with FAS. The five comorbid conditions with the highest pooled prevalence (between 50% and 91%) included abnormal results of function studies of peripheral nervous system and special senses, conduct disorder, receptive language disorder, chronic serous otitis media, and expressive language disorder.

INTERPRETATION

The high prevalence of comorbid conditions in individuals with FASD highlights the importance of assessing prenatal alcohol exposure as a substantial clinical risk factor for comorbidity. The harmful effects of alcohol on a developing fetus represent many cases of preventable disability, and thus, alcohol use during pregnancy should be recognised as a public health problem globally.

FUNDING

Public Health Agency of Canada.

Relationships between Head Circumference, Brain Volume and Cognition in Children with Prenatal Alcohol Exposure

Head circumference is used together with other measures as a proxy for central nervous system damage in the diagnosis of fetal alcohol spectrum disorders, yet the relationship between head circumference and brain volume has not been investigated in this population. The objective of this study is to characterize the relationship between head circumference, brain volume and cognitive performance in a large sample of children with prenatal alcohol exposure (n = 144) and healthy controls (n = 145), aged 5-19 years. All participants underwent magnetic resonance imaging to yield brain volumes and head circumference, normalized to control for age and sex. Mean head circumference, brain volume, and cognitive scores were significantly reduced in the prenatal alcohol exposure group relative to controls, albeit with considerable overlap between groups. Males with prenatal alcohol exposure had reductions in all three measures, whereas females with prenatal alcohol exposure had reduced brain volumes and cognitive scores, but no difference in head circumference relative to controls. Microcephaly (defined here as head circumference ≤ 3rd percentile) occurred more often in prenatal alcohol exposed participants than controls, but 90% of the exposed sample had head circumferences above this clinical cutoff indicating that head circumference is not a sensitive marker of prenatal alcohol exposure. Normalized head circumference and brain volume were positively correlated in both groups, and subjects with very low head circumference typically had below-average brain volumes. Conversely, over half of the subjects with very low brain volumes had normal head circumferences, which may stem from differential effects of alcohol on the skeletal and nervous systems. There were no significant correlations between head circumference and any cognitive score. These findings confirm group-level reductions in head circumference and increased rates of microcephaly in children with prenatal alcohol exposure, but raise concerns about the predictive value of this metric at an individual-subject level.

Autosomal-Recessive Intellectual Disability with Cerebellar Atrophy Syndrome Caused by Mutation of the Manganese and Zinc Transporter Gene SLC39A8

Manganese (Mn) and zinc (Zn) are essential divalent cations used by cells as protein cofactors; various human studies and animal models have demonstrated the importance of Mn and Zn for development. Here we describe an autosomal-recessive disorder in six individuals from the Hutterite community and in an unrelated Egyptian sibpair; the disorder is characterized by intellectual disability, developmental delay, hypotonia, strabismus, cerebellar atrophy, and variable short stature. Exome sequencing in one affected Hutterite individual and the Egyptian family identified the same homozygous variant, c.112G>C (p.Gly38Arg), affecting a conserved residue of SLC39A8. The affected Hutterite and Egyptian individuals did not share an extended common haplotype, suggesting that the mutation arose independently. SLC39A8 is a member of the solute carrier gene family known to import Mn, Zn, and other divalent cations across the plasma membrane. Evaluation of these two metal ions in the affected individuals revealed variably low levels of Mn and Zn in blood and elevated levels in urine, indicating renal wasting. Our findings identify a human Mn and Zn transporter deficiency syndrome linked to SLC39A8, providing insight into the roles of Mn and Zn homeostasis in human health and development.

Visual search for feature conjunctions: an fMRI study comparing alcohol-related neurodevelopmental disorder (ARND) to ADHD

BACKGROUND

Alcohol-related neurodevelopmental disorder (ARND) falls under the umbrella of fetal alcohol spectrum disorder (FASD). Diagnosis of ARND is difficult because individuals do not demonstrate the characteristic facial features associated with fetal alcohol syndrome (FAS). While attentional problems in ARND are similar to those found in attention-deficit/hyperactivity disorder (ADHD), the underlying impairment in attention pathways may be different.

METHODS

Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) was conducted at 3 T. Sixty-three children aged 10 to 14 years diagnosed with ARND, ADHD, and typically developing (TD) controls performed a single-feature and a feature-conjunction visual search task.

RESULTS

Dorsal and ventral attention pathways were activated during both attention tasks in all groups. Significantly greater activation was observed in ARND subjects during a single-feature search as compared to TD and ADHD groups, suggesting ARND subjects require greater neural recruitment to perform this simple task. ARND subjects appear unable to effectively use the very efficient automatic perceptual 'pop-out' mechanism employed by TD and ADHD groups during presentation of the disjunction array. By comparison, activation was lower in ARND compared to TD and ADHD subjects during the more difficult conjunction search task as compared to the single-feature search. Analysis of DTI data using tract-based spatial statistics (TBSS) showed areas of significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) in the right inferior longitudinal fasciculus (ILF) in ARND compared to TD subjects. Damage to the white matter of the ILF may compromise the ventral attention pathway and may require subjects to use the dorsal attention pathway, which is associated with effortful top-down processing, for tasks that should be automatic. Decreased functional activity in the right temporoparietal junction (TPJ) of ARND subjects may be due to a reduction in the white matter tract's ability to efficiently convey information critical to performance of the attention tasks.

CONCLUSIONS

Limited activation patterns in ARND suggest problems in information processing along the ventral frontoparietal attention pathway. Poor integrity of the ILF, which connects the functional components of the ventral attention network, in ARND subjects may contribute to the attention deficits characteristic of the disorder.

CODAS syndrome is associated with mutations of LONP1, encoding mitochondrial AAA+ Lon protease

CODAS syndrome is a multi-system developmental disorder characterized by cerebral, ocular, dental, auricular, and skeletal anomalies. Using whole-exome and Sanger sequencing, we identified four LONP1 mutations inherited as homozygous or compound-heterozygous combinations among ten individuals with CODAS syndrome. The individuals come from three different ancestral backgrounds (Amish-Swiss from United States, n = 8; Mennonite-German from Canada, n = 1; mixed European from Canada, n = 1). LONP1 encodes Lon protease, a homohexameric enzyme that mediates protein quality control, respiratory-complex assembly, gene expression, and stress responses in mitochondria. All four pathogenic amino acid substitutions cluster within the AAA(+) domain at residues near the ATP-binding pocket. In biochemical assays, pathogenic Lon proteins show substrate-specific defects in ATP-dependent proteolysis. When expressed recombinantly in cells, all altered Lon proteins localize to mitochondria. The Old Order Amish Lon variant (LONP1 c.2161C>G[p.Arg721Gly]) homo-oligomerizes poorly in vitro. Lymphoblastoid cell lines generated from affected children have (1) swollen mitochondria with electron-dense inclusions and abnormal inner-membrane morphology; (2) aggregated MT-CO2, the mtDNA-encoded subunit II of cytochrome c oxidase; and (3) reduced spare respiratory capacity, leading to impaired mitochondrial proteostasis and function. CODAS syndrome is a distinct, autosomal-recessive, developmental disorder associated with dysfunction of the mitochondrial Lon protease.

Oncogenic codon 13 NRAS mutation in a primary mesenchymal brain neoplasm and nevus of a child with neurocutaneous melanosis

A 28-month female with a clinical diagnosis of neurocutaneous melanosis and numerous intracranial abnormalities (including a right choroid plexus tumor and left hemimegalencephaly) presented with a rapidly expanding tumor in the left occipital cerebrum. Microscopic examination of the resected specimen revealed a myxoid mesenchymal neoplasm consisting of fusiform cells that were immunoreactive for vimentin, CD34, and P53 but no melanocyte markers. Focused amplicon deep sequencing on DNA extracted from the brain tumor and a cutaneous nevus revealed a heterozygous (c.37G > C; p.G13R) substitution in the NRAS gene. DNA sequencing of “normal” skin and buccal swab showed the identical NRAS change albeit at lower allelic frequency. Her parents did not harbor the NRAS mutation. The skin lesion, but not the brain tumor, had a BRAF mutation (c.1397G > T; p.G466V). A germline single nucleotide polymorphism in MET was found in the child and her father (c.3209C > T; p.T1010I). The findings suggest NRAS mosaicism that occurred sometime after conception and imply an oncogenic role of the activating NRAS mutation in both the brain and skin lesions in this child.

Copy number variants (CNVs) analysis in a deeply phenotyped cohort of individuals with intellectual disability (ID)

Background

DNA copy number variants (CNVs) are found in 15% of subjects with ID but their association with phenotypic abnormalities has been predominantly studied in smaller cohorts of subjects with detailed yet non-systematically categorized phenotypes, or larger cohorts (thousands of cases) with smaller number of generalized phenotypes.

Methods

We evaluated the association of de novo, familial and common CNVs detected in 78 ID subjects with phenotypic abnormalities classified using the Winter-Baraitser Dysmorphology Database (WBDD) (formerly the London Dysmorphology Database). Terminology for 34 primary (coarse) and 169 secondary (fine) phenotype features were used to categorize the abnormal phenotypes and determine the prevalence of each phenotype in patients grouped by the type of CNV they had.

Results

In our cohort more than 50% of cases had abnormalities in primary categories related to head (cranium, forehead, ears, eye globes, eye associated structures, nose) as well as hands and feet. The median number of primary and secondary abnormalities was 12 and 18 per subject, respectively, indicating that the cohort consisted of subjects with a high number of phenotypic abnormalities (median De Vries score for the cohort was 5). The prevalence of each phenotypic abnormality was comparable in patients with de novo or familial CNVs in comparison to those with only common CNVs, although a trend for increased frequency of cranial and forehead abnormalities was noted in subjects with rare de novo and familial CNVs. Two clusters of subjects were identified based on the prevalence of each fine phenotypic feature, with an average of 28.3 and 13.5 abnormal phenotypes/subject in the two clusters respectively (P < 0.05).

Conclusions

Our study is a rare example of using standardized, deep morphologic phenotype clustering with phenotype/CNV correlation in a cohort of subjects with ID. The composition of the cohort inevitably influences the phenotype/genotype association, and our studies show that the influence of the de novo CNVs on the phenotype is less obvious in cohorts consisting of subjects with a high number of phenotypic abnormalities. The outcome of phenotype/genotype analysis also depends on the choice of phenotypes assessed and standardized phenotyping is required to minimize variability.

Lissencephaly with brainstem and cerebellar hypoplasia and congenital cataracts

Classical lissencephaly may be associated with cerebellar hypoplasia and when significant cerebellar abnormalities occur, defects in proteins encoded by TUBA1A, RELN, and very-low-density lipoprotein receptor (VLDLR) genes have been reported. We present a neonate with a severe neurologic phenotype associated with hypotonia, oropharyngeal incoordination that required a gastric tube for feeding, intractable epilepsy, and congenital cataracts. Her brain magnetic resonance imaging (MRI) showed classical lissencephaly, ventriculomegaly, absent corpus callosum, globular and vertical hippocampi, and severe cerebellar and brainstem hypoplasia. She died at 6 weeks of age. No specific molecular diagnosis was made. This likely represents a previously undescribed genetic lissencephaly syndrome.

The differential diagnosis of fetal alcohol spectrum disorder

Fetal Alcohol Spectrum Disorder (FASD) affects an estimated 1% of all children born in North America. FASD is a chronic disorder impacting many systems of care. Only a minority of these children exhibit the pathognomonic facial features of Fetal alcohol syndrome (FAS) that include short palpebral fissures, smooth philtrum and thin upper lip. Hence, in the majority of affected individuals FASD is a diagnosis of exclusion. The differential diagnosis of both the dysmorphological and neurobehavioral aspects of FASD is wide. This review aims to provide the pediatrician with information concerning the differential diagnosis of FASD and to discuss genetic testing that might be relevant to the assessment.

SAMS, a syndrome of short stature, auditory-canal atresia, mandibular hypoplasia, and skeletal abnormalities is a unique neurocristopathy caused by mutations in Goosecoid

Short stature, auditory canal atresia, mandibular hypoplasia, and skeletal abnormalities (SAMS) has been reported previously to be a rare, autosomal-recessive developmental disorder with other, unique rhizomelic skeletal anomalies. These include bilateral humeral hypoplasia, humeroscapular synostosis, pelvic abnormalities, and proximal defects of the femora. To identify the genetic basis of SAMS, we used molecular karyotyping and whole-exome sequencing (WES) to study small, unrelated families. Filtering of variants from the WES data included segregation analysis followed by comparison of in-house exomes. We identified a homozygous 306 kb microdeletion and homozygous predicted null mutations of GSC, encoding Goosecoid homeobox protein, a paired-like homeodomain transcription factor. This confirms that SAMS is a human malformation syndrome resulting from GSC mutations. Previously, Goosecoid has been shown to be a determinant at the Xenopus gastrula organizer region and a segment-polarity determinant in Drosophila. In the present report, we present data on Goosecoid protein localization in staged mouse embryos. These data and the SAMS clinical phenotype both suggest that Goosecoid is a downstream effector of the regulatory networks that define neural-crest cell-fate specification and subsequent mesoderm cell lineages in mammals, particularly during shoulder and hip formation. Our findings confirm that Goosecoid has an essential role in human craniofacial and joint development and suggest that Goosecoid is an essential regulator of mesodermal patterning in mammals and that it has specific functions in neural crest cell derivatives.

Radiographic characterization of the hands in Ritscher-Schinzel/3-C syndrome

Abstract

Ritscher-Schinzel Syndrome (RSS) is a clinically variable, autosomal recessive disorder, involving cardiac, cerebellar and craniofacial abnormalities. Numerous reports describe hand changes in RSS patients; however, a detailed characterization of the hands has not previously been performed.

Objective

The purpose of this study was to identify whether specific radiographic hand changes were characteristic of RSS and could serve as a diagnostic tool.

Materials and methods

We performed a detailed radiographic hand characterization of 8 RSS patients. The patient population consisted of 5 males and 3 females from ages one month to 26 years, 7 months. The hands were characterized using metacarpophalangeal pattern (MCPP) profiles, carpal height and bone age analyses and assessment of bone morphology.

Results

There was generalized brachydactyly with the second ray being the most severely affected. There was significant shortening of the first metacarpal and the fifth distal phalanx. The MCPP profile generated showed a consistent wavy pattern with average Z-scores ranging from -0.15 (4^th proximal phalanx) to -2.13 (1^st metacarpal) and 0.53 (4^th middle phalanx) to -1.73 (2^nd proximal phalanx) for the left and right hands, respectively. Six of eight patients showed a decreased carpal height. Bone age was within normal limits for all patients. Our study population showed consistent radiographic changes including: overtubulation of the bones (especially metacarpals 2-4), prominent tufts of the distal phalanges and a hypoplastic fifth distal phalanx.

Conclusion

The hand findings identified in this study can provide helpful diagnostic tools to clinicians when the diagnosis of RSS is being considered.

A novel mutation in KIAA0196: identification of a gene involved in Ritscher-Schinzel/3C syndrome in a First Nations cohort

BACKGROUND

Ritscher-Schinzel syndrome (RSS) is a clinically heterogeneous disorder characterised by distinctive craniofacial features in addition to cerebellar and cardiac anomalies. It has been described in different populations and is presumed to follow autosomal recessive inheritance. In an effort to identify the underlying genetic cause of RSS, affected individuals from a First Nations (FN) community in northern Manitoba, Canada, were enrolled in this study.

METHODS

Homozygosity mapping by SNP array and Sanger sequencing of the candidate genes in a 1Mb interval on chromosome 8q24.13 were performed on genomic DNA from eight FN RSS patients, eight of their parents and five unaffected individuals (control subjects) from this geographic isolate.

RESULTS

All eight patients were homozygous for a novel splice site mutation in KIAA0196. RNA analysis revealed an approximate eightfold reduction in the relative amount of a KIAA0196 transcript lacking exon 27. A 60% reduction in the amount of strumpellin protein was observed on western blot.

CONCLUSIONS

We have identified a mutation in KIAA0196 as the cause of the form of RSS characterised in our cohort. The ubiquitous expression and highly conserved nature of strumpellin, the product of KIAA0196, is consistent with the complex and multisystem nature of this disorder.

Use of health, education, and social services by individuals with fetal alcohol spectrum disorder

BACKGROUND

Fetal Alcohol Spectrum Disorder (FASD) is the leading cause of intellectual disability in western society, presenting a significant burden on health, education and social services. Quantifying the burden of FASD is important for service planning and policy and program development.

OBJECTIVE

To describe the health, education and social service use of individuals with FASD to provide an indication of the burden of service use of the disorder.

METHODS

Using a matched-cohort design health, education and social service data were linked with clinical records on individuals 6+ years diagnosed with FASD between 1999/2000-2009/10 (N=717). Matching was 2:1 with a general population (gPop) and asthma group by age, sex and area-level income. Adjusted rates and relative risks were calculated using Generalized Linear Models.

RESULTS

Hospitalizations were higher in the FASD compared to gPop (adjusted relative risk=3.44 (95% confidence interval=2.29, 5.17)) and asthma (2.87 (1.94, 4.25)) groups, whereas for physician visits and overall prescriptions, the FASD group differed from only the gPop group (1.58 (1.34, 1.84); 1.44 (1.22, 1.72), respectively). Antibiotics, pain killers and anti-psychotics were similar across groups whereas antidepressants and psychostimulants were higher in the FASD group (antidepressants: FASD vs. gPop 8.76 (2.82, 27.21); FASD vs. asthma 2.10 (1.15, 3.83); psychostimulants: FASD vs. gPop 5.78 (2.89, 11.57); FASD vs. asthma 2.47 (1.37, 4.47)). Attention-deficit\hyperactivity disorder was higher in the FASD than the gPop and asthma groups (6.41 (3.29, 12.49); 3.12 (1.97, 4.93), respectively). Education and social service use was higher for the FASD than either of the other groups for all measures (FASD vs. gPop and FASD vs. asthma, respectively for: grade repetition 3.06 (1.58, 5.94); 3.48 (1.79, 6.78); receipt of any special education funding 9.22 (6.23, 13.64); 6.10 (4.14, 8.99); family receipt of income assistance 1.74 (1.33, 2.27); 1.89 (1.45, 2.47); child in care 13.19 (5.84, 29.78);10.70 (4.80, 23.88); and receipt of child welfare services 5.70 (4.21, 7.71); 4.94 (3.67, 6.66)).

CONCLUSION

The health, education and social service utilization burden of individuals with FASD is substantial, greater than that of individuals in the general population and with chronic illness (i.e., asthma). The findings highlight the need for multisystem supports for those with FASD, and comprehensive prevention programs.

Cost of fetal alcohol spectrum disorder diagnosis in Canada

Background

Fetal Alcohol Spectrum Disorder (FASD) is underdiagnosed in Canada. The diagnosis of FASD is not simple and currently, the recommendation is that a comprehensive, multidisciplinary assessment of the individual be done. The purpose of this study was to estimate the annual cost of FASD diagnosis on Canadian society.

Methods

The diagnostic process breakdown was based on recommendations from the Fetal Alcohol Spectrum Disorder Canadian Guidelines for Diagnosis. The per person cost of diagnosis was calculated based on the number of hours (estimated based on expert opinion) required by each specialist involved in the diagnostic process. The average rate per hour for each respective specialist was estimated based on hourly costs across Canada. Based on the existing clinical capacity of all FASD multidisciplinary clinics in Canada, obtained from the 2005 and 2011 surveys conducted by the Canada Northwest FASD Research Network, the number of FASD cases diagnosed per year in Canada was estimated. The per person cost of FASD diagnosis was then applied to the number of cases diagnosed per year in Canada in order to calculated the overall annual cost.

Results

Using the most conservative approach, it was estimated that an FASD evaluation requires 32 to 47 hours for one individual to be screened, referred, admitted, and diagnosed with an FASD diagnosis, which results in a total cost of $3,110 to $4,570 per person. The total cost of FASD diagnostic services in Canada ranges from $3.6 to $5.2 million (lower estimate), up to $5.0 to $7.3 million (upper estimate) per year.

Discussion

As a result of using the most conservative approach, the cost of FASD diagnostic services presented in the current study is most likely underestimated. The reasons for this likelihood and the limitations of the study are discussed.

The Coffin-Siris syndrome: a proposed diagnostic approach and assessment of 15 overlapping cases

Coffin-Siris syndrome (CSS) is a rare, clinically heterogeneous disorder often considered in the setting of cognitive/developmental delay and 5th finger/nail hypoplasia. Due to the clinical variability of facial and other features, this diagnosis is often difficult to confirm clinically and the existence of this disorder as a specific diagnosis has been at times an issue of debate. In an effort to further delineate the spectrum and key phenotypic features, we reviewed 80 previously reported cases to define features in patients that most closely correlated with a convincing diagnosis. There appear to be two subtypes of CSS, one which displays the "classic" coarse facial features previously described; another displays "variant" facial features which are less striking. Using these features, we defined an algorithm to rank the confidence of diagnosis and applied it to 15 additional patients who had been previously characterized by chromosome microarray. This approach will also facilitate uniform categorization for whole-exome analysis.

Comparison of spatial working memory in children with prenatal alcohol exposure and those diagnosed with ADHD; A functional magnetic resonance imaging study

Background

Alcohol related neurodevelopmental disorder (ARND) falls under the umbrella of fetal alcohol spectrum disorder (FASD), but individuals do not demonstrate the facial characteristics associated with fetal alcohol syndrome (FAS), making diagnosis difficult. While attentional problems in ARND are similar to those found in attention-deficit/hyperactivity disorder (ADHD), the underlying impairment in attention pathways may be different.

Methods

Functional magnetic resonance imaging (fMRI) of a working memory (1-back) task of 63 children, 10 to 14 years old, diagnosed with ARND and ADHD, as well as typically developing (TD) controls, was conducted at 3 T. Diffusion tensor imaging (DTI) data were also acquired.

Results

Activations were observed in posterior parietal and occipital regions in the TD group and in dorsolateral prefrontal and posterior parietal regions in the ARND group, whereas the ADHD group activated only dorsolateral prefrontal regions, during the working memory component of the task (1-back minus 0-back contrast). The increases in frontal and parietal activity were significantly greater in the ARND group compared to the other groups. This increased activity was associated with reduced accuracy and increased response time variability, suggesting that ARND subjects exert greater effort to manage short-term memory load. Significantly greater intra-subject variability, demonstrated by fMRI region-of-interest analysis, in the ADHD and ARND groups compared to the TD group suggests that moment-to-moment lapses in attention contributed to their poorer task performance. Differences in functional activity in ARND subjects with and without a diagnosis of ADHD resulted primarily from reduced activation by the ARND/ADHD + group during the 0-back task. In contrast, children with ADHD alone clearly showed reduced activations during the 1-back task. DTI analysis revealed that the TD group had significantly higher total tract volume and number of fibers than the ARND group. These measures were negatively correlated with errors on the 1-back task, suggesting a link between white matter integrity and task performance.

Conclusions

fMRI activations suggest that the similar behavior of children with ARND and ADHD on a spatial working memory task is the result of different cognitive events. The nature of ADHD in children with ARND appears to differ from that of children with ADHD alone.

Risk factors for nonsyndromic holoprosencephaly: a Manitoba case-control study

Holoprosencephaly (HPE) is one of the most common developmental field defects, occurring in 1 in 250 conceptuses and in 1 in 10,000-20,000 live births. Nearly half of patients with HPE have a recognized syndrome or a single gene defect. However, little is known about the risk factors for the remainder with "nonsyndromic" HPE. In our case-control study, we examine factors associated with nonsyndromic HPE. We identified 47 patients with HPE from the genetics clinic database with an equal number of controls matched for gender and birthdate. Of the 47 patients, 23 were identified as nonsyndromic. No statistically significant differences were noted between the mean maternal and paternal ages of patients and controls. Factors associated with nonsyndromic HPE were: having an Aboriginal mother (unadjusted odds ratio [OR] 3.5, 95% confidence interval [CI] 1.1-11.1), an Aboriginal father (OR 12.8, 95% CI 3.0-55.1), at least one Aboriginal parent (OR 5.0, 95% CI 1.6-16.0), or two Aboriginal parents (OR 8.8, 95% CI 2.0-37.8), the presence of a family history of a midline facial defect (OR 8.2, 95% CI 1.5-45.2), and being of low socioeconomic status (OR 3.0, 95% CI 1.0-9.1). Having an Aboriginal background remained statistically significant after adjusting for low socioeconomic status. Other associations evaluated--history of prior spontaneous abortion, stillbirth, neonatal death, prepregnancy diabetes, infections during pregnancy, alcohol exposure, smoking, and substance abuse--were not significantly associated with nonsyndromic HPE. The use of periconceptional folic acid or vitamins was not associated with a lower risk of nonsyndromic HPE.

Correlates of age at diagnosis of autism spectrum disorders in six Canadian regions

INTRODUCTION

Early identification of autism spectrum disorders (ASD) is important, since earlier exposure to behavioural intervention programs may result in better outcomes for the child. Moreover, it allows families timely access to other treatments and supports.

METHODS

Using generalized linear modeling, we examined the association between child and family characteristics and the age at which 2180 children were diagnosed with ASD between 1997 and 2005 in six Canadian regions.

RESULTS

A diagnosis of pervasive developmental disorder-not otherwise specified (PDD-NOS) or Asperger syndrome, rural residence, diagnosis in more recent years, and foreign birthplace were associated with a later age at diagnosis. Children who are visible minorities or who have siblings with ASD were more likely to be diagnosed earlier. Collectively, these factors explained little of the variation in age at diagnosis, however.

CONCLUSION

While it is encouraging that ethnocultural identity, neighbourhood income, urban or rural residence, and sex of the child were not major contributors to disparities in the age when children were identified with ASD, more work is needed to determine what does account for the differences observed. Regional variations in the impact of several factors suggest that aggregating data may not be an optimal strategy if the findings are meant to inform policy and clinical practice at the local level.

Functional magnetic resonance imaging of facial information processing in children with autistic disorder, attention deficit hyperactivity disorder and typically developing controls

The present study used functional magnetic resonance imaging (fMRI) to compare the neural activation patterns of children diagnosed with autistic disorder (AD), attention deficit hyperactivity disorder (ADHD), and typically developing controls (TCs) in response to a task involving evaluation of facial expressions. Substantially greater functional activity was noted in TCs compared to both subjects diagnosed with AD and ADHD. Consistent with previous studies, differences in functional activation of the amygdala, fusiform gyrus, cerebellum, mesolimbic, and temporal lobe cortical regions of the brain during a task evaluating facial expressions were noted in AD compared to TCs. Differences in the neural activity in these brain regions were also observed in children diagnosed with AD compared to those diagnosed with ADHD. Overall decreased neural activity was observed during the faces task performance in the AD group compared to the other two groups, a finding consistent with studies using adults. Both TC and ADHD control groups showed increased inferior frontal cortex activity compared to the AD group. Significant activity was present in both TC and ADHD control groups in the insula which was absent in the AD group; this is consistent with other studies showing dysfunction of the mesolimbic system in children with AD. Although frontostriatal and mesolimbic systems appear to be affected in AD, these deficits were not in the same attentional networks which are dysfunctional in children diagnosed with ADHD.

Microdeletion 9q22.3 syndrome includes metopic craniosynostosis, hydrocephalus, macrosomia, and developmental delay

Basal cell nevus syndrome (BCNS), also known as Gorlin syndrome (OMIM #109400) is a well-described rare autosomal dominant condition due to haploinsufficiency of PTCH1. With the availability of comparative genomic hybridization arrays, increasing numbers of individuals with microdeletions involving this locus are being identified. We present 10 previously unreported individuals with 9q22.3 deletions that include PTCH1. While 7 of the 10 patients (7 females, 3 males) did not meet strict clinical criteria for BCNS at the time of molecular diagnosis, almost all of the patients were too young to exhibit many of the diagnostic features. A number of the patients exhibited metopic craniosynostosis, severe obstructive hydrocephalus, and macrosomia, which are not typically observed in BCNS. All individuals older than a few months of age also had developmental delays and/or intellectual disability. Only facial features typical of BCNS, except in those with prominent midforeheads secondary to metopic craniosynostosis, were shared among the 10 patients. The deletions in these individuals ranged from 352  kb to 20.5  Mb in size, the largest spanning 9q21.33 through 9q31.2. There was significant overlap of the deleted segments among most of the patients. The smallest common regions shared among the deletions were identified in order to localize putative candidate genes that are potentially responsible for each of the non-BCNS features. These were a 929  kb region for metopic craniosynostosis, a 1.08  Mb region for obstructive hydrocephalus, and a 1.84  Mb region for macrosomia. Additional studies are needed to further characterize the candidate genes within these regions.

TMEM237 is mutated in individuals with a Joubert syndrome related disorder and expands the role of the TMEM family at the ciliary transition zone

Joubert syndrome related disorders (JSRDs) have broad but variable phenotypic overlap with other ciliopathies. The molecular etiology of this overlap is unclear but probably arises from disrupting common functional module components within primary cilia. To identify additional module elements associated with JSRDs, we performed homozygosity mapping followed by next-generation sequencing (NGS) and uncovered mutations in TMEM237 (previously known as ALS2CR4). We show that loss of the mammalian TMEM237, which localizes to the ciliary transition zone (TZ), results in defective ciliogenesis and deregulation of Wnt signaling. Furthermore, disruption of Danio rerio (zebrafish) tmem237 expression produces gastrulation defects consistent with ciliary dysfunction, and Caenorhabditis elegans jbts-14 genetically interacts with nphp-4, encoding another TZ protein, to control basal body-TZ anchoring to the membrane and ciliogenesis. Both mammalian and C. elegans TMEM237/JBTS-14 require RPGRIP1L/MKS5 for proper TZ localization, and we demonstrate additional functional interactions between C. elegans JBTS-14 and MKS-2/TMEM216, MKSR-1/B9D1, and MKSR-2/B9D2. Collectively, our findings integrate TMEM237/JBTS-14 in a complex interaction network of TZ-associated proteins and reveal a growing contribution of a TZ functional module to the spectrum of ciliopathy phenotypes.

2p15-p16.1 microdeletion syndrome: molecular characterization and association of the OTX1 and XPO1 genes with autism spectrum disorders

Reports of unrelated individuals with autism spectrum disorder (ASD) and similar clinical features having overlapping de novo interstitial deletions at 2p15-p16.1 suggest that this region harbors a gene(s) important to the development of autism. We molecularly characterized two such deletions, selecting two genes in this region, exportin 1 (XPO1) and orthodenticle homolog 1 (OTX1) for association studies in three North American cohorts (Autism Spectrum Disorder - Canadian American Research Consortium (ASD-CARC), New York, and Autism Genetic Resource Exchange (AGRE)) and one Italian cohort (Società Italiana per la Ricerca e la Formazione sull'Autismo (SIRFA)) of families with ASD. In XPO1, rs6735330 was associated with autism in all four cohorts (P<0.05), being significant in ASD-CARC cohorts (P-value following false discovery rate correction for multiple testing (P(FDR))=1.29 × 10(-5)), the AGRE cohort (P(FDR)=0.0011) and the combined families (P(FDR)=2.34 × 10(-9)). Similarly, in OTX1, rs2018650 and rs13000344 were associated with autism in ASD-CARC cohorts (P(FDR)=8.65 × 10(-7) and 6.07 × 10(5), respectively), AGRE cohort (P(FDR)=0.0034 and 0.015, respectively) and the combined families (P(FDR)=2.34 × 10(-9) and 0.00017, respectively); associations were marginal or insignificant in the New York and SIRFA cohorts. A significant association (P(FDR)=2.63 × 10(-11)) was found for the rs2018650G-rs13000344C haplotype. The above three SNPs were associated with severity of social interaction and verbal communication deficits and repetitive behaviors (P-values <0.01). No additional deletions were identified following screening of 798 ASD individuals. Our results indicate that deletion 2p15-p16.1 is not commonly associated with idiopathic ASD, but represents a novel contiguous gene syndrome associated with a constellation of phenotypic features (autism, intellectual disability, craniofacial/CNS dysmorphology), and that XPO1 and OXT1 may contribute to ASD in 2p15-p16.1 deletion cases and non-deletion cases of ASD mapping to this chromosome region.

Trends in telehealth versus on-site clinical genetics appointments in Manitoba: a comparative study

Telehealth involves the use of information and communications technology to deliver health services to patients over distance. Canada is well suited to benefit from telehealth since many individuals live in remote, rural and isolated locations. Manitoba is the easternmost prairie province and MBTelehealth is an active Canadian program that currently has 105 sites in 73 communities. Although studies of patient satisfaction comparing telehealth to on-site clinical visits have been conducted, a comparative study of the types of genetics patients seen via these two modalities has not been performed previously. In this study we: (1) examined the uptake of telehealth in Genetics in Manitoba; (2) contrasted telehealth usage in Genetics with other clinical programs; and (3) performed a comparative study of the types of Genetics referrals seen in 2008 on-site versus via telehealth. Results indicate the uptake of telehealth is increasing and has made genetics outreach clinics unnecessary. The Program of Genetics and Metabolism is consistently one of the top ten utilizers of telehealth within the province. With respect to discipline, chi square analysis revealed the trends were not significantly different for on-site and telehealth encounters, with prenatal referrals being the most common and Hereditary Breast and Ovarian Cancer referrals being the least common. Referrals within each discipline varied depending on the need for fetal assessment and physical examination. Telehealth was utilized regularly for test results sessions across all disciplines.

Congenital rickets caused by maternal vitamin D deficiency

The cases of four newborn infants with congenital rickets are reported. All infants were native Canadian: three were Cree and one was Inuit. One had a narrow chest and pulmonary hypoplasia, two had clinical and radiological signs of rickets with craniotabes, thickened wrists, and prominent costochondral junctions, and one had perinatal asphyxia and hydrops. All had hypocalcemia, hypophosphatemia and secondary hyperparathyroidism. Serum 25-hydroxyvitamin D levels were low in three of the infants. The four mothers had evidence of vitamin D deficiency. All infants recovered following treatment with 5000 IU oral vitamin D daily.

Manitoba-oculo-tricho-anal (MOTA) syndrome is caused by mutations in FREM1

BACKGROUND

Manitoba-oculo-tricho-anal (MOTA) syndrome is a rare condition defined by eyelid colobomas, cryptophthalmos and anophthalmia/microphthalmia, an aberrant hairline, a bifid or broad nasal tip, and gastrointestinal anomalies such as omphalocele and anal stenosis. Autosomal recessive inheritance had been assumed because of consanguinity in the Oji-Cre population of Manitoba and reports of affected siblings, but no locus or cytogenetic aberration had previously been described.

METHODS AND RESULTS

This study shows that MOTA syndrome is caused by mutations in FREM1, a gene previously mutated in bifid nose, renal agenesis, and anorectal malformations (BNAR) syndrome. MOTA syndrome and BNAR syndrome can therefore be considered as part of a phenotypic spectrum that is similar to, but distinct from and less severe than, Fraser syndrome. Re-examination of Frem1(bat/bat) mutant mice found new evidence that Frem1 is involved in anal and craniofacial development, with anal prolapse, eyelid colobomas, telecanthus, a shortened snout and reduced philtral height present in the mutant mice, similar to the human phenotype in MOTA syndrome.

CONCLUSIONS

The milder phenotypes associated with FREM1 deficiency in humans (MOTA syndrome and BNAR syndrome) compared to that resulting from FRAS1 and FREM2 loss of function (Fraser syndrome) are also consistent with the less severe phenotypes resulting from Frem1 loss of function in mice. Together, Fraser, BNAR and MOTA syndromes constitute a clinically overlapping group of FRAS-FREM complex diseases.