The genetic basis of cerebral palsy

Association of Gestational Age at Birth and Changes on MRI With Prevalence and Spectrum of Comorbidities in Children With Cerebral Palsy

BACKGROUND AND OBJECTIVES

For individuals with cerebral palsy (CP) and caregivers, comorbidities may be a greater challenge than neuromotor impairment. Clinicians may make assumptions regarding risk of comorbidities based simply on term vs preterm birth, but this has not been well examined. To better understand factors affecting comorbidity pattern, we investigated the relationship between gestational age (GA) and imaging pattern on the presence of specific comorbidities.

METHODS

This is a cross-sectional study of data extracted from the Canadian Cerebral Palsy Registry of children with CP. Multivariable analysis was used to evaluate the relationship between brain injury, GA, and comorbidities. Comorbidities included in the analysis were communication, cognitive, visual, and auditory impairment, seizures in the past year, and gavage feeding. Each comorbidity was assessed as a separate nonexclusive outcome, with GA, MRI pattern, birth weight, postneonatal insult, 5-minute Apgar score, and male sex considered as potential modifiers.

RESULTS

The only comorbidity affected by GA on multivariable analysis was seizures within the past year that were more prevalent in term children (odds ratio [OR] 1.1 95% CI 1.0-1.2) and was also affected by Apgar score (OR 0.9 95% CI 0.85-0.94), but not MRI pattern. MRI pattern appeared important for communication impairment (deep gray OR 4.2 95% CI 1.8-10.0; total brain injury OR 8.5, 95% CI 3.2-22.6; malformation OR 2.7, 95% CI 1.3-5.7) and cognitive impairment (deep gray OR 5.6, 95% CI 2.4-13.2; total brain injury OR 10.1, 95% CI 4.0-25.3; malformation OR 3.3, 95% CI 1.6-6.8; watershed OR 3.6, 95% CI 1.4-8.9). Focal injury compared with normal MRI was associated with reduced odds of visual impairment (OR 0.24, 95% CI 0.12-0.48), auditory impairment (OR 0.2195% CI 0.10-0.46) and communication impairment (OR 0.46, 95% CI 0.26-0.82), and overall number of comorbidities (coefficient -0.73, 95% CI -1.2 to -0.31). The number of comorbidities was increased by total brain injury pattern (coefficient 0.65, 95% CI 0.15-1.13) and reduced by focal brain injury (coefficient -0.73, 95% CI -1.2 to -0.31) and increasing 5-minute Apgar score (coefficient -0.11, 95% CI -0.16 to -0.07).

DISCUSSION

In those with brain injuries sufficient to cause CP, development of additional comorbidities is less affected by GA at birth and more related to the underlying cause of CP as reflected by MRI patterns.

Clinical features associated with epilepsy occurrence, resolution, and drug resistance in children with cerebral palsy: A population-based study

AIM

To investigate clinicoradiological features associated with epilepsy, its resolution, and drug resistance in children with cerebral palsy (CP).

METHOD

Data were gathered from the New South Wales/Australian Capital Territory CP Register, encompassing children with CP born between 2003 and 2015 (n = 1916). Clinical features and the severity of impairments were compared among three groups: children with current epilepsy (n = 604), those with resolved epilepsy by age 5 years (n = 109), and those without epilepsy (n = 1203). Additionally, a subset of the registry cohort attending Children's Hospital Westmead (n = 256) was analysed to compare epilepsy and treatment characteristics between drug-responsive (n = 83) and drug-resistant groups (n = 147) using logistic regression and hierarchical cluster analysis.

RESULTS

Manual Ability Classification System levels IV and V, intellectual impairment, and vision impairment were found to be associated with epilepsy in children with CP on multivariable analysis (p < 0.01). Moderate to severe intellectual impairment and bilateral spastic CP were independent positive and negative predictors of epilepsy persistence at the age of 5 years respectively (p < 0.05). Microcephaly and multiple seizure types were predictors of drug-resistant epilepsy (area under the receiver operating characteristic curve of 0.83; 95% confidence interval 0.77-0.9). Children with a known genetic cause (14%) and CP epilepsy surgery group (4.3%) formed specific clinical subgroups in CP epilepsy.

INTERPRETATION

Our study highlights important clinical associations of epilepsy, its resolution, and treatment response in children with CP, providing valuable knowledge to aid in counselling families and identifying distinct prognostic groups for effective medical surveillance and optimal treatment.

WHAT THIS PAPER ADDS

Severe motor and non-motor impairments in cerebral palsy (CP) increase epilepsy risk. Epilepsy more likely resolves in bilateral spastic and milder CP impairments. Epilepsy in CP often manifests at an early age with multiple seizure types and high drug resistance. Children with a known genetic cause and CP epilepsy surgery group represent distinct clinical subgroups.

Current approach to cerebral palsy

This teaching review aims to provide an overview of the current approach to children with cerebral palsy (CP), retrieving the best available evidence and summarizing existing knowledge in the field of CP in children. We also highlight areas where more research is needed and novel strategies for diagnosing and treating cerebral palsy. CP includes a group of permanent disorders of movement and posture that cause activity limitation. Multiple risk factors, occurring preconceptionally, prenatally, perinatally, or postneonatally, are involved in the pathogenesis of CP, with the prenatal ones accounting for 80-90 % of cases. Due to its heterogeneity, CP has various classifications, but usually is classified based on clinical findings and motor impairment. Standardized function classification systems have been developed to address inconsistencies in previous classifications. The combination of clinical assessment and validated predictive tools is recommended for an early diagnosis, which is important for early intervention and prevention of secondary impairments. The therapeutic regimen in CP involves prevention and management of the motor and associated problems. It includes the enhancement of motor performance, the enrichment of cognition and communication skills, the prevention of secondary impairments, and the support of parents and caregivers. The care of CP children demands a multidisciplinary approach focused on improving motor skills, reducing comorbidities, enhancing the quality of life, and prolonging survival.

Clinical Characteristics Suggestive of a Genetic Cause in Cerebral Palsy: A Systematic Review

BACKGROUND

Cerebral palsy (CP) is a clinical diagnosis and was long categorized as an acquired disorder, but more and more genetic etiologies are being identified. This review aims to identify the clinical characteristics that are associated with genetic CP to aid clinicians in selecting candidates for genetic testing.

METHODS

The PubMed database was systematically searched to identify genes associated with CP. The clinical characteristics accompanying these genetic forms of CP were compared with published data of large CP populations resulting in the identification of potential indicators of genetic CP.

RESULLTS

Of 1930 articles retrieved, 134 were included. In these, 55 CP genes (described in two or more cases, n = 272) and 79 candidate genes (described in only one case) were reported. The most frequently CP-associated genes were PLP1 (21 cases), ARG1 (17 cases), and CTNNB1 (13 cases). Dyskinesia and the absence of spasticity were identified as strong potential indicators of genetic CP. Presence of intellectual disability, no preterm birth, and no unilateral distribution of symptoms were classified as moderate genetic indicators.

CONCLUSIONS

Genetic causes of CP are increasingly identified. The clinical characteristics associated with genetic CP can aid clinicians regarding to which individual with CP to offer genetic testing. The identified potential genetic indicators need to be validated in large CP cohorts but can provide the first step toward a diagnostic algorithm for genetic CP.

Association Between Assisted Reproductive Technology and Cerebral Palsy: A Meta-Analysis

BACKGROUND

Since 1978 many children are born thanks to assisted reproductive technology (ART). However, the long-term effects of these therapies are still not fully known. Our objective is to evaluate the risk of cerebral palsy (CP) after ART compared with that in those spontaneously conceived (SC) and to examine this risk in single, multiple, and preterm births and the evolution of the risk over the years.

METHODS

PubMed, Embase, and Web of Science databases were searched until December 2022. Studies were included if they studied CP cases in children born through ART. 16 studies were finally selected. Quality of studies was assessed using Newcastle Ottawa Scale. Pooled OR was estimated by weighting individual OR/RR by the inverse of their variance. A random-effect model was applied. To assess the causes of heterogeneity, we performed meta-regression analyses.

RESULTS

A significantly high risk of CP was found (OR = 1.27; 95% CI 1.12 to 1.43) in children born through ART compared with those SC. This risk increased in singletons (OR = 1.48; 95% CI 1.23 to 1.79) but disappeared in multiple (OR = 1.05; 95% CI 0.93 to 1.18) and preterm births (OR = 1.09; 95% CI 0.87 to 1.37). We found a higher risk of CP in children born before the year 2000 (OR = 3.40; 95% CI 2.49 to 4.63).

CONCLUSIONS

ARTs slightly increase the risk of CP once the effect of multiple gestation is controlled. Further studies are needed to clarify whether the techniques themselves, fertility problems, or associated maternal comorbidities are responsible for this risk.

Case report: Suspecting guanine nucleotide-binding protein beta 1 mutation in dyskinetic cerebral palsy is important

Herein, we describe the case of a 43-month-old girl who presented with clinical manifestations of dyskinetic cerebral palsy (CP), classified as the Gross Motor Function Classification System (GMFCS) V. The patient had no family history of neurological or perinatal disorders. Despite early rehabilitation, serial assessments using the Gross Motor Function Measure (GMFM) showed no significant improvements in gross motor function. Brain magnetic resonance imaging showed nonspecific findings that could not account for developmental delay or dystonia. Whole-genome sequencing identified a heterozygous NM_002074.5(GNB1):c.239T>C (p.Ile80Thr) mutation in guanine nucleotide-binding protein beta 1 (GNB1) gene. Considering this case and previous studies, genetic testing for the etiology of dyskinetic CP is recommended for children without relevant or with nonspecific brain lesions.

AGAP1-associated endolysosomal trafficking abnormalities link gene-environment interactions in neurodevelopmental disorders

AGAP1 is an Arf1 GTPase-activating protein that regulates endolysosomal trafficking. Damaging variants have been linked to cerebral palsy and autism. We report three new cases in which individuals had microdeletion variants in AGAP1. The affected individuals had intellectual disability (3/3), autism (3/3), dystonia with axial hypotonia (1/3), abnormalities of brain maturation (1/3), growth impairment (2/3) and facial dysmorphism (2/3). We investigated mechanisms potentially underlying AGAP1 variant-mediated neurodevelopmental impairments using the Drosophila ortholog CenG1a. We discovered reduced axon terminal size, increased neuronal endosome abundance and elevated autophagy compared to those in controls. Given potential incomplete penetrance, we assessed gene-environment interactions. We found basal elevation in the phosphorylation of the integrated stress-response protein eIF2α (or eIF2A) and inability to further increase eIF2α phosphorylation with subsequent cytotoxic stressors. CenG1a-mutant flies had increased lethality from exposure to environmental insults. We propose a model wherein disruption of AGAP1 function impairs endolysosomal trafficking, chronically activating the integrated stress response and leaving AGAP1-deficient cells susceptible to a variety of second-hit cytotoxic stressors. This model may have broader applicability beyond AGAP1 in instances where both genetic and environmental insults co-occur in individuals with neurodevelopmental disorders.

Prevalence of cerebral palsy and factors associated with cerebral palsy subtype: A population-based study in Belgium

AIM

To report on the prevalence, neuroimaging patterns, and function of children with cerebral palsy (CP) in Belgium for birth years 2007-2012, and identify distinctive risk indicators and differences in outcome between CP subtypes.

METHODS

Antenatal and perinatal/neonatal factors, motor and speech function, associated impairments, and neuroimaging patterns were extracted from the Belgian Cerebral Palsy Register. Prevalence was estimated per 1000 (overall, ante/perinatal, spastic, dyskinetic CP) or 10,000 (post-neonatal, ataxic CP) live births. Multinomial logistic regression analyses were performed to ascertain the effects of antenatal/perinatal/neonatal factors and neuroimaging patterns on the likelihood of dyskinetic or ataxic CP relative to spastic CP, and test the likelihood of the occurrence of impaired motor and speech function and associated impairments in dyskinetic or ataxic CP relative to spastic CP.

RESULTS

In total, 1127 children with CP were identified in Belgium. The birth prevalence of overall CP was 1.48 per 1000 live births. The likelihood of dyskinetic CP increases if the child was born to a mother aged ≥35 years, mechanically ventilated, and had predominant grey matter injury, while an increased likelihood of ataxic CP is associated with ≥2 previous deliveries. Children with dyskinetic and ataxic CP are more likely to function with impairments in motor, speech, and intellectual abilities.

CONCLUSION

Distinctive risk indicators and differences in outcome between CP subtypes were identified. These factors can be incorporated into clinical practice to facilitate early, accurate, and reliable classification of CP subtype, and may lead to individually tailored neonatal care and other (early) intervention options.

Comorbidities in children with cerebral palsy: a single-centre cross-sectional hospital-based study from India

OBJECTIVE

To describe the comorbidities in children with cerebral palsy (CP) and determine the characteristics associated with different impairments.

DESIGN

Cross-sectional study.

SETTING

Tertiary care referral centre in India.

PATIENTS

Between April 2018 and May 2022, all children aged 2-18 years with a confirmed diagnosis of CP were enrolled by systematic random sampling. Data on antenatal, birth and postnatal risk factors, clinical evaluation and investigations (neuroimaging and genetic/metabolic workup) were recorded.

MAIN OUTCOME MEASURES

Prevalence of the co-occurring impairments was determined using clinical evaluation or investigations as indicated.

RESULTS

Of the 436 children screened, 384 participated (spastic CP=214 (55.7%) (spastic hemiplegic=52 (13.5%); spastic diplegia=70 (18.2%); spastic quadriplegia=92 (24%)), dyskinetic CP=58 (15.1%) and mixed CP=110 (28.6%)). A primary antenatal/perinatal/neonatal and postneonatal risk factor was identified in 32 (8.3%), 320 (83.3%) and 26 (6.8%) patients, respectively. Prevalent comorbidities (the test used) included visual impairment (clinical assessment and visual evoked potential)=357/383(93.2%), hearing impairment (brainstem-evoked response audiometry)=113 (30%), no understanding of any communication (MacArthur Communicative Development Inventory)=137 (36%), cognitive impairment (Vineland scale of social maturity)=341 (88.8%), severe gastrointestinal dysfunction (clinical evaluation/interview)=90 (23%), significant pain (non-communicating children's pain checklist)=230 (60%), epilepsy=245 (64%), drug-resistant epilepsy=163 (42.4%), sleep impairment (Children's Sleep Habits Questionnaire)=176/290(60.7%) and behavioural abnormalities (Childhood behaviour checklist)=165 (43%). Overall, hemiparetic and diplegic CP and Gross Motor Function Classification System ≤3 were predictive of lesser co-occurring impairment.

CONCLUSION

CP children have a high burden of comorbidities, which increase with increasing functional impairment. This calls for urgent actions to prioritise opportunities to prevent risk factors associated with CP and organise existing resources to identify and manage co-occurring impairments.

TRIAL REGISTRATION NUMBER

CTRI/2018/07/014819.

Uncertainties regarding cerebral palsy diagnosis: opportunities to operationalize the consensus definition

Background and Objectives

Cerebral palsy (CP), the most common motor disability of childhood, is variably diagnosed. We hypothesized that child neurologists and neurodevelopmentalists, often on the frontlines of CP diagnosis in North America, harbor uncertainties regarding the practical application of the most recent CP consensus definition from 2006.

Methods

We conducted a cross-sectional survey of child neurologists and neurodevelopmentalists at the 2022 Child Neurology Society Annual Meeting. Attendees were provided the 2006 CP consensus definition and asked whether they had any uncertainties about the practical application of the definition across four hypothetical clinical vignettes.

Results

Of 230 attendees, 164 responded to the closing survey questions (71%). 145/164 (88%) expressed at least one uncertainty regarding the clinical application of the 2006 definition. Overwhelmingly, these areas of uncertainty focused on: 1) Age, both with regards to the minimum age of diagnosis and the maximum age of brain disturbance or motor symptom onset, (67/164, 41%), and 2) Interpretation of the term "non-progressive" (48/164, 29%). The vast majority of respondents (157/164, 96%) answered 'Yes' to the question: Do you think we should revise the 2006 consensus definition of CP?

Discussion

We propose that the uncertainties we identified could be addressed by operationalizing the 2006 consensus definition to support a more uniform CP diagnosis. To address the most common CP diagnostic uncertainties we identified, we propose 3 points of clarification based on the available literature: 1) Motor symptoms/signs should be present by 2 years old; 2) CP can and should be diagnosed as early as possible, even if activity limitation is not yet present, if motor symptoms/signs can be reasonably predicted to yield activity limitation (e.g. by using standardized examination instruments, Brain MRI, and a suggestive clinical history); and 3) The clinical motor disability phenotype should be non-progressive through 5 years old. We anticipate that operationalizing the 2006 definition of CP in this manner could clarify the uncertainties we identified among child neurologists and neurodevelopmentalists and reduce the diagnostic variability that currently exists.

Advances in Genetics and Epigenetics of Developmental Coordination Disorder in Children

Developmental coordination disorder (DCD) is a developmental disorder characterized by impaired motor coordination, often co-occurring with attention deficit disorder, autism spectrum disorders, and other psychological and behavioural conditions. The aetiology of DCD is believed to involve brain changes and environmental factors, with genetics also playing a role in its pathogenesis. Recent research has identified several candidate genes and genetic factors associated with motor impairment, including deletions, copy number variations, single nucleotide polymorphisms, and epigenetic modifications. This review provides an overview of the current knowledge in genetic research on DCD, highlighting the importance of continued research into the underlying genetic mechanisms. While evidence suggests a genetic contribution to DCD, the evidence is still in its early stages, and much of the current evidence is based on studies of co-occurring conditions. Further research to better understand the genetic basis of DCD could have important implications for diagnosis, treatment, and our understanding of the condition's aetiology.

Predictors of whole exome sequencing in dystonic cerebral palsy and cerebral palsy-like disorders

INTRODUCTION

Cerebral palsy (CP) is a group of permanent disorders attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. Cerebral palsy-like (CP-like) disorders may clinically resemble CP but do not fulfill CP criteria and have often a progressive course and/or neurodevelopmental regression. To assess which patients with dystonic CP and dystonic CP-like disorder should undergo Whole Exome Sequencing (WES), we compared the rate of likely causative variants in individuals regarding their clinical picture, co-morbidities, and environmental risk factors.

METHOD

Individuals with early onset neurodevelopmental disorder (ND) manifesting with dystonia as a core feature were divided into CP or CP-like cohorts based on their clinical picture and disease course. Detailed clinical picture, co-morbidities, and environmental risk factors including prematurity, asphyxia, SIRS, IRDS, and cerebral bleeding were evaluated.

RESULTS

A total of 122 patients were included and divided into the CP group with 70 subjects (30 males; mean age 18y5m±16y6m, mean GMFCS score 3.3 ± 1.4), and the CP-like group with 52 subjects (29 males; mean age 17y7m±1y,6 m, mean GMFCS score 2,6 ± 1,5). The WES-based diagnosis was present in 19 (27.1%) CP patients and 30 CP-like patients (57.7%) with genetic conditions overlap in both groups. We found significant differences in diagnostic rate in CP individuals with vs. without risk factors (13.9% vs. 43.3%); Fisher's exact p = 0.0065. We did not observe the same tendency in CP-like (45.5% vs 58.5%); Fisher's exact p = 0.5.

CONCLUSION

WES is a useful diagnostic method for patients with dystonic ND, regardless of their presentation as a CP or CP-like phenotype.

Development of a Bedside Tool to Predict the Diagnosis of Cerebral Palsy in Term-Born Neonates

Importance

Cerebral palsy (CP) is the most common abnormality of motor development and causes lifelong impairment. Early diagnosis and therapy can improve outcomes, but early identification of infants at risk remains challenging.

Objective

To develop a CP prognostic tool that can be applied to all term neonates to identify those at increased risk of developing CP.

Design, Setting, and Participants

This case-control study used data from the Canadian Cerebral Palsy Registry (data collected from January 2003 to December 2019) for children with CP and the Alberta Pregnancy Outcomes and Nutrition study (mothers enrolled from May 2009 to September 2012; data extracted in 2020) for controls. There were 2771 children with CP and 2131 controls evaluated; 941 and 144, respectively, were removed for gestational age less than 37 weeks at birth, 565 with CP removed for incomplete data, and 2 controls removed for a diagnosis of CP. Data were analyzed from April to August 2022.

Exposures

Potential risk factors were selected a priori based on the literature, including maternal, intrapartum, and infant characteristics.

Main Outcomes and Measures

Diagnosis of CP, defined as a disorder of motor function due to a nonprogressive brain abnormality before age 1 year and classified by Gross Motor Function Classification System levels I to V.

Results

Of 3250 included individuals, 1752 (53.9%) were male, and the median (IQR) gestational age at birth was 39 (38-40) weeks. Encephalopathy was present in 335 of 1184 infants with CP (28%) and 0 controls. The final prediction model included 12 variables and correctly classified 75% of infants, with a sensitivity of 56% (95% CI, 52-60) and specificity of 82% (95% CI, 81-84). The C statistic was 0.74 (95% CI, 71-76). Risk factors were found to be additive. A proposed threshold for screening is probability greater than 0.3, with a sensitivity of 65% (95% CI, 61-68) and specificity of 71% (95% CI, 69-73). The prognostic tool identified 2.4-fold more children with CP than would have presented with encephalopathy (odds ratio, 13.8; 95% CI, 8.87-22.65; P < .001).

Conclusions and Relevance

In this case-control study, a prognostic model using 12 clinical variables improved the prediction of CP compared with clinical presentation with encephalopathy. This tool can be applied to all term newborns to help select infants for closer surveillance or further diagnostic tests, which could improve outcomes through early intervention.

AGAP1-associated endolysosomal trafficking abnormalities link gene-environment interactions in a neurodevelopmental disorder

AGAP1 is an Arf1 GAP that regulates endolysosomal trafficking. Damaging variants have been linked to cerebral palsy and autism. We report 3 new individuals with microdeletion variants in AGAP1 . Affected individuals have intellectual disability (3/3), autism (3/3), dystonia with axial hypotonia (1/3), abnormalities of brain maturation (1/3), growth impairment (2/3) and facial dysmorphism (2/3). We investigated mechanisms potentially underlying AGAP1 neurodevelopmental impairments using the Drosophila ortholog, CenG1a . We discovered reduced axon terminal size, increased neuronal endosome abundance, and elevated autophagy at baseline. Given potential incomplete penetrance, we assessed gene-environment interactions. We found basal elevation in phosphorylation of the integrated stress-response protein eIF2α and inability to further increase eIF2α-P with subsequent cytotoxic stressors. CenG1a -mutant flies have increased lethality from exposure to environmental insults. We propose a model wherein disruption of AGAP1 function impairs endolysosomal trafficking, chronically activating the integrated stress response, and leaving AGAP1-deficient cells susceptible to a variety of second hit cytotoxic stressors. This model may have broader applicability beyond AGAP1 in instances where both genetic and environmental insults co-occur in individuals with neurodevelopmental disorders.

Summary statement

We describe 3 additional patients with heterozygous AGAP1 deletion variants and use a loss of function Drosophila model to identify defects in synaptic morphology with increased endosomal sequestration, chronic autophagy induction, basal activation of eIF2α-P, and sensitivity to environmental stressors.

Identifying Genetic Susceptibility in Neonates With Hypoxic-Ischemic Encephalopathy: A Retrospective Case Series

Neonatal hypoxic-ischemic encephalopathy is a clinical phenomenon that often results from perinatal asphyxia. To mitigate secondary neurologic injury, prompt initial assessment and diagnosis is needed to identify patients eligible for therapeutic hypothermia. However, occasionally neonates present with a clinical picture of hypoxic-ischemic encephalopathy without significant risk factors for perinatal asphyxia. We hypothesized that in patients with genetic abnormalities, the clinical manifestation of those abnormalities may overlap with hypoxic-ischemic encephalopathy criteria, potentially contributing to a causal misattribution. We reviewed 210 charts of infants meeting local protocol criteria for moderate to severe hypoxic-ischemic encephalopathy in neonatal intensive care units in Calgary, Alberta. All patients that met criteria for therapeutic hypothermia were eligible for the study. Data were collected surrounding pregnancy and birth histories, as well as any available genetic or metabolic testing including microarray, gene panels, whole-exome sequencing, and newborn metabolic screens. Twenty-eight patients had genetic testing such as microarray, whole-exome sequencing, or a gene panel, because of clinical suspicion. Ten of 28 patients had genetic mutations, including CDKL5, pyruvate dehydrogenase, CFTR, CYP21A2, ISY1, KIF1A, KCNQ2, SCN9A, MTFMT, and NPHP1. All patients lacked significant risk factors to support a moderate to severe hypoxic-ischemic encephalopathy diagnosis. Treatment was changed in 2 patients because of confirmed genetic etiology. This study demonstrates the importance of identifying genetic comorbidities as potential contributors to a hypoxic-ischemic encephalopathy phenotype in neonates. Early identification of clinical factors that support an alternate diagnosis should be considered when the patient's clinical picture is not typical of hypoxic-ischemic encephalopathy and could aid in both treatment decisions and outcome prognostication.

Cerebral palsy and related neuromotor disorders: Overview of genetic and genomic studies

Cerebral palsy (CP) is a debilitating condition characterized by abnormal movement or posture, beginning early in development. Early family and twin studies and more recent genomic investigations clearly demonstrate that genetic factors of major effect contribute to the etiology of CP. Most copy number variants and small alterations of nucleotide sequence that cause CP arise as a result of de novo mutations, so studies that estimate heritability on basis of recurrence frequency within families substantially underestimate genetic contributions to the etiology. At least 4% of patients with typical CP have disease-causing CNVs, and at least 14% have disease-causing single nucleotide variants or indels. The rate of pathogenic genomic lesions is probably more than twice as high among patients who have atypical CP, i.e., neuromotor dysfunction with additional neurodevelopmental abnormalities or malformations, or with MRI findings and medical history that are not characteristic of a perinatal insult. Mutations of many different genetic loci can produce a CP-like phenotype. The importance of genetic variants of minor effect and of epigenetic modifications in producing a multifactorial predisposition to CP is less clear. Recognizing the specific cause of CP in an affected individual is essential to providing optimal clinical management. An etiological diagnosis provides families an "enhanced compass" that improves overall well-being, facilitates access to educational and social services, permits accurate genetic counseling, and, for a subset of patients such as those with underlying inherited metabolic disorders, may make precision therapy that targets the pathophysiology available. Trio exome sequencing with assessment of copy number or trio genome sequencing with bioinformatics analysis for single nucleotide variants, indels, and copy number variants is clinically indicated in the initial workup of CP patients, especially those with additional malformations or neurodevelopmental abnormalities.

Common data elements to standardize genomics studies in cerebral palsy

AIM

To define clinical common data elements (CDEs) and a mandatory minimum data set (MDS) for genomic studies of cerebral palsy (CP).

METHOD

Candidate data elements were collated following a review of the literature and existing CDEs. An online, three-round Delphi survey was used to rate each data element as either 'core', 'recommended', 'exploratory', or 'not required'. Members of the International Cerebral Palsy Genomics Consortium (ICPGC) rated the core CDEs as either mandatory or not, to form the MDS. For both the CDEs and the MDS, a data element was considered to have reached consensus if more than 75% of respondents agreed.

RESULTS

Forty-six individuals from around the world formed the Delphi panel: consumers (n=2), scientists/researchers (n=17), medical (n=19), and allied health professionals (n=8). The CDEs include 107 data elements across six categories: demographics, diagnostics, family history, antenatal and neonatal details, clinical traits, and CP-specific assessments. Of these, 10 are mandatory, 42 core, 41 recommended, and 14 are exploratory.

INTERPRETATION

The ICPGC CDEs provide a foundation for the standardization of phenotype data captured in CP genomic studies and will benefit international collaborations and pooling of data, particularly in rare conditions.

WHAT THIS PAPER ADDS

A set of 107 common data elements (CDEs) for genomics studies in cerebral palsy is provided. The CDEs include standard definitions and data values domains. The CDEs will facilitate international data sharing, collaboration, and improved clinical interpretation of findings.

DNA Methylation Analysis Reveals Distinct Patterns in Satellite Cell-Derived Myogenic Progenitor Cells of Subjects with Spastic Cerebral Palsy

Spastic type cerebral palsy (CP) is a complex neuromuscular disorder that involves altered skeletal muscle microanatomy and growth, but little is known about the mechanisms contributing to muscle pathophysiology and dysfunction. Traditional genomic approaches have provided limited insight regarding disease onset and severity, but recent epigenomic studies indicate that DNA methylation patterns can be altered in CP. Here, we examined whether a diagnosis of spastic CP is associated with intrinsic DNA methylation differences in myoblasts and myotubes derived from muscle resident stem cell populations (satellite cells; SCs). Twelve subjects were enrolled (6 CP; 6 control) with informed consent/assent. Skeletal muscle biopsies were obtained during orthopedic surgeries, and SCs were isolated and cultured to establish patient-specific myoblast cell lines capable of proliferation and differentiation in culture. DNA methylation analyses indicated significant differences at 525 individual CpG sites in proliferating SC-derived myoblasts (MB) and 1774 CpG sites in differentiating SC-derived myotubes (MT). Of these, 79 CpG sites were common in both culture types. The distribution of differentially methylated 1 Mbp chromosomal segments indicated distinct regional hypo- and hyper-methylation patterns, and significant enrichment of differentially methylated sites on chromosomes 12, 13, 14, 15, 18, and 20. Average methylation load across 2000 bp regions flanking transcriptional start sites was significantly different in 3 genes in MBs, and 10 genes in MTs. SC derived MBs isolated from study participants with spastic CP exhibited fundamental differences in DNA methylation compared to controls at multiple levels of organization that may reveal new targets for studies of mechanisms contributing to muscle dysregulation in spastic CP.

Providing a Primary Care Medical Home for Children and Youth With Cerebral Palsy

Cerebral palsy (CP) is the most common motor disorder of childhood, with prevalence estimates ranging from 1.5 to 4 in 1000 live births. This clinical report seeks to provide primary care physicians with guidance to detect children with CP; collaborate with specialists in treating the patient; manage associated medical, developmental, and behavioral problems; and provide general medical care to their patients with CP.

Making waves: The changing tide of cerebral palsy

Cerebral palsy (CP) is a broad diagnosis unbound by aetiology and is based on a clinical examination demonstrating abnormalities of movement or posture. CP represents a static neurological condition, provided that neurodegenerative conditions, leukoencephalopathies and neuromuscular disorders are excluded. In paediatrics, the genetic conditions associated with CP are rapidly increasing, with primary and overlapping neurodevelopmental conditions perhaps better categorised by the predominant clinical feature such as CP, intellectual disability, autism spectrum disorder or epilepsy. Progress in molecular genetics may challenge what constitutes CP, but a genetic diagnosis does not negate the CP diagnosis. As clinicians working in the field, we discuss the changing tide of CP. Neuroimaging provides essential information through pattern recognition and demonstration of static brain changes. We present examples of children where a layered clinical diagnosis or dual aetiologies are appropriate. We also present examples of children with genetic causes of CP to highlight the challenges and limitations of neuroimaging to provide an aetiological diagnosis. In consultation with a geneticist, access to genomic testing (exome or genome sequencing) is now available in Australia under Medicare billing for children under the age of 10 with dysmorphic features, one or more major structural organ anomalies, (an evolving) intellectual disability or global developmental delay. We encourage the uptake of genomic testing in CP, because it can be difficult to tell whether a child has an environmental or genetic cause for CP. A specific genetic diagnosis may change patient management, reduce guilt and enable more distinctive research in the future to assist with understanding disease mechanisms.

Cerebral Palsy: Current Concepts and Practices in Musculoskeletal Care

Cerebral palsy is a neurologic disorder characterized by a spectrum of motor and cognitive deficits resulting from insults to the developing brain. The etiologies are numerous and likely multifactorial; an increasing portion of cases may be attributable to genetic causes, although the exact mechanisms responsible remain poorly understood. Major risk factors include intrauterine stroke and prematurity and neonatal infection, trauma, and hypoxia, which may occur in the prenatal, perinatal, or postnatal period. The Gross Motor Function Classification System (GMFCS) is a widely used tool to establish a child's level of function and to guide treatment; however, additional metrics are necessary to formulate long-term prognoses. Goals of care are to maximize function and independence, which directly correlate with overall quality of life, and family participation is key to establishing goals early in treatment. Nonpharmaceutical treatments include physical, occupational, and speech therapy, as well as bracing, equipment, and technology. There is a breadth of medical interventions for managing hypertonia, including medications, botulinum toxin injections, intrathecal baclofen pumps, and selective dorsal rhizotomy. Orthopedic interventions are indicated for symptomatic or progressive musculoskeletal sequelae. Treatments for dysplastic hips and/or hip instability range from soft tissue releases to bony procedures. Neuromuscular scoliosis is managed with posterior spinal fusion because bracing is ineffective against these rapidly progressive curves. The degree of care varies considerably depending on the child's baseline GMFCS level and functional capabilities, and early screening, diagnosis, and appropriate referrals are paramount to initiating early care and maximizing the child's quality of life.

Hereditary spastic paraparesis (HSP) presenting as cerebral palsy due to ADD3 variant with mechanistic insight provided by a Drosophila γ-adducin model

INTRODUCTION

Cerebral palsy (CP) causes neurological disability in early childhood. Hypoxic-ischaemic injury plays a major role in its aetiology, nevertheless, genetic and epigenetic factors may contribute to the clinical presentation. Mutations in ADD3 (encoding γ-adducin) gene have been described in a monogenic form of spastic quadriplegic cerebral palsy (OMIM 601568).

METHODS

We studied a sixteen-year-old male with spastic diplegia. Several investigations including neurometabolic testing, brain and spine magnetic resonance imaging (MRI) and CGH-Array were normal. Further, clinical genetics assessment and Whole Exome Sequencing (WES) gave the diagnosis. We generated an animal model using Drosophila to study the effects of γ-adducin loss and gain of function.

RESULTS

WES revealed a biallelic variant in the ADD3 gene, NM_016824.5(ADD3): c.1100G>A, p.(Gly367Asp). Mutations in this gene have been described as an ultra-rare autosomal recessive which is a known form of inherited cerebral palsy. Molecular modelling suggests that this mutation leads to a loss of structural integrity of γ-adducin and is therefore expected to result in a decreased level of functional protein. Pan-neuronal over-expression or knock-down of the Drosophila ortholog of ADD3 called hts caused a reduction of life span and impaired locomotion thereby phenocopying aspects of the human disease.

CONCLUSION

Our animal experiments present a starting point to understand the biological processes underpinning the clinical phenotype and pathogenic mechanisms, to gain insights into potential future methods for treating or preventing ADD3 related spastic quadriplegic cerebral palsy.

A Review on Recent Advances of Cerebral Palsy

This narrative review summarizes the latest advances in cerebral palsy and identifies where more research is required. Several studies on cerebral palsy were analyzed to generate a general idea of the prevalence of, risk factors associated with, and classification of cerebral palsy (CP). Different classification systems used for the classification of CP on a functional basis were also analyzed. Diagnosis systems used along with the prevention techniques were discussed. State-of-the-art treatment strategies for CP were also analyzed. Statistical distribution was performed based on the selected studies. Prevalence was found to be 2-3/1000 lives; the factors that can be correlated are gestational age and birth weight. The risk factors identified were preconception, prenatal, perinatal, and postnatal categories. According to the evidence, CP is classified into spastic (80%), dyskinetic (15%), and ataxic (5%) forms. Diagnosis approaches were based on clinical investigation and neurological examinations that include magnetic resonance imaging (MRI), biomarkers, and cranial ultrasound. The treatment procedures found were medical and surgical interventions, physiotherapy, occupational therapy, umbilical milking, nanomedicine, and stem cell therapy. Technological advancements in CP were also discussed. CP is the most common neuromotor disability with a prevalence of 2-3/1000 lives. The highest contributing risk factor is prematurity and being underweight. Several preventions and diagnostic techniques like MRI and ultrasound were being used. Treatment like cord blood treatment nanomedicine and stem cell therapy needs to be investigated further in the future to apply in clinical practice. Future studies are indicated in the context of technological advancements among cerebral palsy children.

Diagnostic preferences include discussion of etiology for adults with cerebral palsy and their caregivers

AIM

To determine the views of individuals with cerebral palsy (CP) and their caregivers (CP community members) about carrying a CP diagnosis, an etiological diagnosis, or both diagnoses together.

METHOD

We surveyed CP community members across two registries querying their views on carrying a CP diagnosis, one type of etiological diagnosis (specifically, a genetic diagnosis), or both. Open-ended responses were analyzed using a conventional content analysis approach.

RESULTS

Of 197 respondents (108 adults with CP and 89 caregivers), most (75%) valued knowing the cause of their CP. Of those with a diagnostic preference, most preferred carrying both CP and etiological diagnoses together (68%). When compared with carrying an etiological diagnosis alone, significantly more respondents felt a CP diagnosis helped anticipate symptom evolution (84% vs 54%), explain symptoms to others (86% vs 48%), access services (86% vs 48%), and join support communities (78% vs 50%) (p <  0.01, χ² test).

INTERPRETATION

Most CP community members surveyed want to know the cause of their CP and would prefer carrying both CP and etiological diagnoses together. Clinical practice should evolve to meet these community needs.

Neurodevelopmental disorders, immunity, and cancer are connected

Immunity could be viewed as the common factor in neurodevelopmental disorders and cancer. The immune and nervous systems coevolve as the embryo develops. Immunity can release cytokines that activate MAPK signaling in neural cells. In specific embryonic brain cell types, dysregulated signaling that results from germline or embryonic mutations can promote changes in chromatin organization and gene accessibility, and thus expression levels of essential genes in neurodevelopment. In cancer, dysregulated signaling can emerge from sporadic somatic mutations during human life. Neurodevelopmental disorders and cancer share similarities. In neurodevelopmental disorders, immunity, and cancer, there appears an almost invariable involvement of small GTPases (e.g., Ras, RhoA, and Rac) and their pathways. TLRs, IL-1, GIT1, and FGFR signaling pathways, all can be dysregulated in neurodevelopmental disorders and cancer. Although there are signaling similarities, decisive differentiating factors are timing windows, and cell type specific perturbation levels, pointing to chromatin reorganization. Finally, we discuss drug discovery.

Dysregulation of multiple signaling pathways: A possible cause of cerebral palsy

Cerebral palsy (CP) is a lifelong disability characterized by the impairment of brain functions that result in improper posture and abnormal motor patterns. Understanding this brain abnormality and the role of genetic, epigenetic, and non-genetic factors such as signaling pathway dysregulation and cytokine dysregulation in the pathogenesis of CP is a complex process. Hypoxic-ischemic injury and prematurity are two well-known contributors of CP. Like in the case of other neurodevelopmental disorders such as intellectual disability and autism, the genomic constituents in CP are highly complex. The neuroinflammation that is triggered by maternal cytokine response plays a critical role in the pathogenesis of fetal inflammation response, which is one of the contributing factors of CP, and it continues even after the birth of children suffering from CP. Canonical Wnt signaling pathway is important for the development of mammalian fetal brain and it regulates distinct processes including neurogenesis. The glycogen synthase kinase-3 (GSK-3) antagonistic activity in the Wnt signaling pathway plays a crucial role in neurogenesis and neural development. In this review, we investigated several genetic and non-genetic pathways that are involved in the pathogenesis of CP and their regulation, impairment, and implications for causing CP during embryonic growth and developmental period. Investigating the role of these pathways help to develop novel therapeutic interventions and biomarkers for early diagnosis and treatment. This review also helps us to comprehend the mechanical approach of various signaling pathways, as well as their consequences and relevance in the understanding of CP.

How can same-gene mutations promote both cancer and developmental disorders?

The question of how same-gene mutations can drive both cancer and neurodevelopmental disorders has been puzzling. It has also been puzzling why those with neurodevelopmental disorders have a high risk of cancer. Ras, MEK, PI3K, PTEN, and SHP2 are among the oncogenic proteins that can harbor mutations that encode diseases other than cancer. Understanding why some of their mutations can promote cancer, whereas others promote neurodevelopmental diseases, and why even the same mutations may promote both phenotypes, has important clinical ramifications. Here, we review the literature and address these tantalizing questions. We propose that cell type–specific expression of the mutant protein, and of other proteins in the respective pathway, timing of activation (during embryonic development or sporadic emergence), and the absolute number of molecules that the mutations activate, alone or in combination, are pivotal in determining the pathological phenotypes—cancer and (or) developmental disorders.

Multiple Functions of the Dmrt Genes in the Development of the Central Nervous System

The Dmrt genes encode the transcription factor containing the DM (doublesex and mab-3) domain, an intertwined zinc finger-like DNA binding module. While Dmrt genes are mainly involved in the sexual development of various species, recent studies have revealed that Dmrt genes, which belong to the DmrtA subfamily, are differentially expressed in the embryonic brain and spinal cord and are essential for the development of the central nervous system. Herein, we summarize recent studies that reveal the multiple functions of the Dmrt genes in various aspects of vertebrate neural development, including brain patterning, neurogenesis, and the specification of neurons.

Genetic testing in individuals with cerebral palsy

AIM To determine which patients with cerebral palsy (CP) should undergo genetic testing, we compared the rate of likely causative genetic variants from whole-exome sequencing in individuals with and without environmental risk factors. METHOD Patients were part of a convenience and physician-referred cohort recruited from a single medical center, and research whole-exome sequencing was completed. Participants were evaluated for the following risk factors: extreme preterm birth, brain bleed or stroke, birth asphyxia, brain malformations, and intrauterine infection. RESULTS A total of 151 unrelated individuals with CP (81 females, 70 males; mean age 25y 7mo [SD 17y 5mo], range 3wks-72y) participated. Causative genetic variants were identified in 14 participants (9.3%). There was no significant difference in diagnostic rate between individuals with risk factors (10 out of 123; 8.1%) and those without (4 out of 28; 14.3%) (Fisher's exact p=0.3). INTERPRETATION While the rate of genetic diagnoses among individuals without risk factors was higher than those with risk factors, the difference was not statistically significant at this sample size. The identification of genetic diagnoses in over 8% of cases with risk factors suggests that these might confer susceptibility to environmental factors, and that further research should include individuals with risk factors. What this paper adds There is no significant difference in diagnostic rate between individuals with and without risk factors. Genetic variants may confer susceptibility to environmental risk factors. Six causative variants were identified in genes not previously associated with cerebral palsy. Global developmental delay/intellectual disability is positively associated with a genetic etiology. Extreme preterm birth, stroke/brain hemorrhage, and older age are negatively associated with a genetic etiology.

An Emerging Role for Epigenetics in Cerebral Palsy

Cerebral palsy is a set of common, severe, motor disabilities categorized by a static, nondegenerative encephalopathy arising in the developing brain and associated with deficits in movement, posture, and activity. Spastic CP, which is the most common type, involves high muscle tone and is associated with altered muscle function including poor muscle growth and contracture, increased extracellular matrix deposition, microanatomic disruption, musculoskeletal deformities, weakness, and difficult movement control. These muscle-related manifestations of CP are major causes of progressive debilitation and frequently require intensive surgical and therapeutic intervention to control. Current clinical approaches involve sophisticated consideration of biomechanics, radiologic assessments, and movement analyses, but outcomes remain difficult to predict. There is a need for more precise and personalized approaches involving omics technologies, data science, and advanced analytics. An improved understanding of muscle involvement in spastic CP is needed. Unfortunately, the fundamental mechanisms and molecular pathways contributing to altered muscle function in spastic CP are only partially understood. In this review, we outline evidence supporting the emerging hypothesis that epigenetic phenomena play significant roles in musculoskeletal manifestations of CP.

People with Cerebral Palsy and Their Family's Preferences about Genomics Research

INTRODUCTION

The goal of this study was to understand individuals with cerebral palsy (CP) and their family's attitudes and preferences to genomic research, including international data sharing and biobanking.

METHODS

Individuals with CP and their family members were invited to participate in the web-based survey via email (NSW/ACT CP Register) or via posts on social media by Cerebral Palsy Alliance, CP Research Network, and CP Now. Survey responses included yes/no/unsure, multiple choices, and Likert scales. Fisher's exact and χ2 tests were used to assess if there were significant differences between subgroups.

RESULTS

Individuals with CP and their families (n = 145) were willing to participate in genomics research (68%), data sharing (82%), and biobanking efforts (75%). This willingness to participate was associated with completion of tertiary education, previous genetic testing experience, overall higher genomic awareness, and trust in international researchers. The survey respondents also expressed ongoing communication and diverse information needs regarding the use of their samples and data. Major concerns were associated with privacy and data security.

DISCUSSION

The success of genomic research and international data sharing efforts in CP are contingent upon broad support and recruitment. Ongoing consultation and engagement of individuals with CP and their families will facilitate trust and promote increased awareness of genomics in CP that may in turn maximize participant uptake and recruitment.

Hearing Loss Diagnosis and Early Hearing-Related Interventions in Infants With or at High Risk for Cerebral Palsy: A Systematic Review

AIM

To synthesize published evidence regarding hearing impairment diagnosis and interventions in infants with or at high risk for cerebral palsy in the first year after birth.

METHOD

Nine databases were searched for MeSH terms up to February 2020. Included studies were published in English, enrolled infants with or at high risk for cerebral palsy, and addressed hearing evaluation/rehabilitation within the first year after birth. Quality of evidence was evaluated using RTI Item Bank and QUADAS-2.

RESULTS

Eighteen articles met inclusion criteria. Quality of the evidence ranged from low to high, revealing variability in diagnostic assessment methodologies and adherence to diagnostic schedules. Concerns for bias included lack of recognition of cerebral palsy effects and etiologies on functional hearing assessment methods and results. Two interventions (hearing aid and cochlear implantation) were identified; however, reported use was inconsistent.

INTERPRETATION

Hearing screening in infants with or at high risk for cerebral palsy requires evaluation of the entire auditory pathway preferentially using comprehensive electrophysiological panels of assessments. For infants with perinatal neural insults, pediatric neurologists are uniquely positioned to recommend adherence to systematic surveillance and comprehensive audiology assessments, regardless of comorbidities and motor impairments.

Genome-Wide Association Study Identifies Genetic Risk Factors for Spastic Cerebral Palsy

BACKGROUND

Although many clinical risk factors of spastic cerebral palsy (CP) have been identified, the genetic basis of spastic CP is largely unknown. Here, using whole-genome genetic information linked to a deidentified electronic health record (BioVU) with replication in the UK Biobank and FinnGen, we perform the first genome-wide association study (GWAS) for spastic CP.

OBJECTIVE

To define the genetic basis of spastic CP.

METHODS

Whole-genome data were obtained using the multi-ethnic genotyping array (MEGA) genotyping array capturing single-nucleotide polymorphisms (SNPs), minor allele frequency (MAF) > 0.01, and imputation quality score (r2) > 0.3, imputed based on the 1000 genomes phase 3 reference panel. Threshold for genome-wide significance was defined after Bonferroni correction for the total number of SNPs tested (P < 5.0 × 10-8). Replication analysis (defined as P < .05) was performed in the UK Biobank and FinnGen.

RESULTS

We identify 1 SNP (rs78686911) reaching genome-wide significance with spastic CP. Expression quantitative trait loci (eQTL) analysis suggests that rs78686911 decreases expression of GRIK4, a gene that encodes a high-affinity kainate glutamatergic receptor of largely unknown function. Replication analysis in the UK Biobank and FinnGen reveals additional SNPs in the GRIK4 loci associated with CP.

CONCLUSION

To our knowledge, we perform the first GWAS of spastic CP. Our study indicates that genetic variation contributes to CP risk.

Cerebral palsy in children born after assisted reproductive technology: a meta-analysis

BACKGROUND

Several studies have assessed the association between cerebral palsy (CP) and assisted reproductive technology (ART), but the results remain controversial. We conducted a meta-analysis to evaluate the risk of CP after ART compared with natural conceptions and to examine CP risk separately in ART singletons, multiples and preterm births.

METHODS

Web-based databases (PubMed, Embase, the Cochrane Library, and Web of Science) were searched until November 22, 2020. Studies which compare CP rates after ART with natural conceptions were included. The Newcastle-Ottawa Scale was used to assess the quality of the included studies. Effect estimates were extracted and combined using the fixed-effects or random-effects model depending on the heterogeneity test.

RESULTS

There were nine studies included in the meta-analysis. The included studies were of moderate or high quality. A significantly higher risk of CP [odds ratio (OR) = 2.17, 95% confidence interval (CI) 1.72-2.74] was found in ART children (n = 89,214) compared with naturally conceived children (n = 4,160,745). The significantly higher risk decreased when data were restricted to singletons (OR = 1.36, 95% CI 1.16-1.59) and disappeared when data were restricted to multiples (OR = 1.05, 95% CI 0.86-1.29) or preterm births (OR = 1.53, 95% CI 0.66-3.56). Subgroup and sensitivity analyses indicated that the overall results were robust.

CONCLUSIONS

The risk of CP is increased more than two-fold after ART. This increased risk is largely due to increased rates of multiple birth and preterm delivery in ART children.

Diagnostic yield of chromosomal microarray and trio whole exome sequencing in cryptogenic cerebral palsy

OBJECTIVE

To determine the yield of genetic diagnoses using chromosomal microarray (CMA) and trio whole exome sequencing (WES), separately and combined, among patients with cryptogenic cerebral palsy (CP).

METHODS

Trio WES of patients with prior CMA analysis for cryptogenic CP, defined as disabling, non-progressive motor symptoms beginning before the age of 3 years without known cause.

RESULTS

Given both CMA analysis and trio WES, clinically significant genetic findings were identified for 58% of patients (26 of 45). Diagnoses were eight large CNVs detected by CMA and 18 point mutations detected by trio WES. None had more than one severe mutation. Approximately half of events (14 of 26) were de novo. Yield was significantly higher in patients with CP with comorbidities (69%, 22 of 32) than in those with pure motor CP (31%, 4 of 13; p=0.02). Among patients with genetic diagnoses, CNVs were more frequent than point mutations among patients with congenital anomalies (OR 7.8, 95% CI 1.2 to 52.4) or major dysmorphic features (OR 10.5, 95% CI 1.4 to 73.7). Clinically significant mutations were identified in 18 different genes: 14 with known involvement in CP-related disorders and 4 responsible for other neurodevelopmental conditions. Three possible new candidate genes for CP were ARGEF10, RTF1 and TAOK3.

CONCLUSIONS

Cryptogenic CP is genetically highly heterogeneous. Genomic analysis has a high yield and is warranted in all these patients. Trio WES has higher yield than CMA, except in patients with congenital anomalies or major dysmorphic features, but these methods are complementary. Patients with negative results with one approach should also be tested by the other.

SATB2-associated syndrome caused by a novel SATB2 mutation in a Chinese boy: A case report and literature review

BACKGROUND

Special AT-rich sequence binding protein 2 (SATB2)-associated syndrome (SAS; OMIM 612313) is an autosomal dominant disorder. Alterations in the SATB2 gene have been identified as causative.

CASE SUMMARY

We report a case of a 13-year-old Chinese boy with lifelong global developmental delay, speech and language delay, and intellectual disabilities. He had short stature and irregular dentition, but no other abnormal clinical findings. A de novo heterozygous nonsense point mutation was detected by genetic analysis in exon 6 of SATB2, c.687C>A (p.Y229X) (NCBI reference sequence: NM_001172509.2), and neither of his parents had the mutation. This mutation is the first reported and was evaluated as pathogenic according to the guidelines from the American College of Medical Genetics and Genomics. SAS was diagnosed, and special education performed. Our report of a SAS case in China caused by a SATB2 mutation expanded the genotype options for the disease. The heterogeneous manifestations can be induced by complicated pathogenic involvements and functions of SATB2 from reviewed literatures: (1) SATB2 haploinsufficiency; (2) the interference of truncated SATB2 protein to wild-type SATB2; and (3) different numerous genes regulated by SATB2 in brain and skeletal development in different developmental stages.

CONCLUSION

Global developmental delays are usually the initial presentations, and the diagnosis was challenging before other presentations occurred. Regular follow-up and genetic analysis can help to diagnose SAS early. Verification for genes affected by SATB2 mutations for heterogeneous manifestations may help to clarify the possible pathogenesis of SAS in the future.

Identifying the Critical Threshold for Long-Term Pediatric Neurological Hospitalizations of the Offspring in Preterm Delivery

We opted to investigate whether a critical threshold exists for long-term pediatric neurological morbidity, and cerebral palsy (CP), in preterm delivery, via a population-based cohort analysis. Four study groups were classified according to their gestational age at birth: 24–27.6, 28–31.6, 32–36.6 weeks and term deliveries, evaluating the incidence of long-term hospitalizations of the offspring due to neurological morbidity. Cox proportional hazard models were performed to control for confounders. A Kaplan–Meier survival curve was used to compare the cumulative neurological morbidity incidence for each group. A total of 220,563 deliveries were included: 0.1% (118) occurred at 24–27.6 weeks of gestation, 0.4% (776) occurred at 28–31.6 weeks of gestation, 6% (13,308) occurred at 32–36.6 weeks of gestation and 93% (206,361) at term. In a Cox model, while adjusting for confounders, delivery before 25 weeks had a 3.9-fold risk for long-term neurological morbidity (adjusted HR (hazard ratio) = 3.9, 95% CI (confidence interval) 2.3–6.6; p < 0.001). The Kaplan–Meier survival curve demonstrated a linear association between long-term neurological morbidity and decreasing gestational age. In a second Cox model, adjusted for confounders, infants born before 25 weeks of gestation had increased rates of CP (adjusted HR = 62.495% CI 25.6–152.4; p < 0.001). In our population, the critical cut-off for long-term neurological complications is delivery before 25 weeks gestation.

In-depth analysis reveals complex molecular aetiology in a cohort of idiopathic cerebral palsy

Cerebral palsy is the most prevalent physical disability in children; however, its inherent molecular mechanisms remain unclear. In the present study, we performed in-depth clinical and molecular analysis on 120 idiopathic cerebral palsy families, and identified underlying detrimental genetic variants in 45% of these patients. In addition to germline variants, we found disease-related postzygotic mutations in ∼6.7% of cerebral palsy patients. We found that patients with more severe motor impairments or a comorbidity of intellectual disability had a significantly higher chance of harbouring disease-related variants. By a compilation of 114 known cerebral-palsy-related genes, we identified characteristic features in terms of inheritance and function, from which we proposed a dichotomous classification system according to the expression patterns of these genes and associated cognitive impairments. In two patients with both cerebral palsy and intellectual disability, we revealed that the defective TYW1, a tRNA hypermodification enzyme, caused primary microcephaly and problems in motion and cognition by hindering neuronal proliferation and migration. Furthermore, we developed an algorithm and demonstrated in mouse brains that this malfunctioning hypermodification specifically perturbed the translation of a subset of proteins involved in cell cycling. This finding provided a novel and interesting mechanism for congenital microcephaly. In another cerebral palsy patient with normal intelligence, we identified a mitochondrial enzyme GPAM, the hypomorphic form of which led to hypomyelination of the corticospinal tract in both human and mouse models. In addition, we confirmed that the aberrant Gpam in mice perturbed the lipid metabolism in astrocytes, resulting in suppressed astrocytic proliferation and a shortage of lipid contents supplied for oligodendrocytic myelination. Taken together, our findings elucidate novel aspects of the aetiology of cerebral palsy and provide insights for future therapeutic strategies.

Are COL4A1 and COL4A2 gene polymorphisms associated with cerebral palsy?

Objectives

This study aims to investigate the association of COL4A1 and COL4A2 gene polymorphisms with susceptibility to risk of developing cerebral palsy (CP) and severity of CP.

Patients and methods

Between December 2016 and June 2017, a total of 176 patients with CP (101 males, 75 females; mean age 71.8±37.9 months; range, 24 to 184 months) and age-, sex-, and ethnically-matched 178 (90 males, 88 females; mean age 69.3±55.2 months; range, 24 to 214 months) controls were included. Two polymorphisms of COL4A1 (rs1961495) and COL4A2 (rs9521733) genes were typed from genomic deoxyribonucleic acid. Genotype distributions and allelic frequencies were compared between the patient and control groups. Gross Motor Function Classification System, the use of medical drugs, type of involvement, number of affected limbs, accompanying conditions, birth weight, gestational age, and magnetic resonance imaging (MRI) findings were used to evaluate the disease severity and their relationships with the COL4A1 and COL4A2 gene polymorphisms.

Results

There was no statistically significant difference between the groups in terms of genotype distribution and allele frequency of COL4A1 and COL4A2 gene polymorphisms (p>0.05). In addition, there was no relationship between severity of CP and two gene polymorphisms (p>0.05). A significant association was detected between the COL4A2 polymorphism and growth retardation in CP. The TT genotype (57.1%) and T allele (76.2%) were higher, compared to CC (4.8%) and CT genotypes (38.1%) and C allele (23.8%) in patients with CP with growth retardation (p=0.03 for genotype and p=0.01 for allele frequency).

Conclusion

These findings suggest that COL4A1 and COL4A2 gene polymorphisms are not associated with susceptibility to CP in a group of Turkish populations, although COL4A2 gene polymorphism may be associated with growth retardation in patients with CP.

Cerebral palsy in Canadian Indigenous children

AIM

To determine whether inequities in health outcomes for Indigenous Canadians are also present in cerebral palsy (CP) by comparing CP profiles between Indigenous and non-Indigenous children.

METHOD

Using the Canadian Cerebral Palsy Registry, we conducted a cross-sectional study. CP motor subtype, gross motor severity, comorbidities, perinatal adversity, preterm birth, and parental education were compared between 94 Indigenous (53 males, 41 females) and 1555 non-Indigenous (891 males, 664 females) children (all >5y). Multivariate analysis was done to analyze adverse CP factors, defined as CP gross motor severity and comorbidities. CP etiologies, either prenatal/perinatal or postnatal, were also compared.

RESULTS

Indigenous children with CP have higher odds of having low parental education (odds ratio [OR] 6.15, 95% confidence interval [CI] 3.36-11.3) and comorbidities (OR 4.46, 95% CI 1.62-12.3), especially cognitive (OR 4.52, 95% CI 2.27-9.05), communication (OR 2.66, 95% CI 1.54-4.61), and feeding (OR 2.25, 95% CI 1.33-3.83) impairment. Indigenous children also have higher CP gross motor severity (p=0.03). Indigenous children are also more likely to have non-accidental head injury (n=4; OR 8.18, 95% CI 1.86-36.0) as the cause of their postnatal CP.

INTERPRETATION

Indigenous populations have worse health outcomes as a result of intergenerational impacts of colonization. Our study shows that Indigenous children with CP have increased comorbidities and higher CP gross motor severity, reinforcing the need for a multidisciplinary approach to management. Furthermore, targeted prevention programs against preventable causes of CP, such as non-accidental head injury, may be beneficial.

WHAT THIS PAPER ADDS

Indigenous children with cerebral palsy (CP) have more severe motor impairment and more comorbidities. Non-accidental head injury is a significant cause of postnatal CP.

Evidence that autosomal recessive spastic cerebral palsy-1 (CPSQ1) is caused by a missense variant in HPDL

A subset of individuals diagnosed with cerebral palsy will have an underlying genetic diagnosis. Previously, a missense variant in GAD1 was described as a candidate mutation in a single family diagnosed with autosomal recessive spastic cerebral palsy-1 (CPSQ1; OMIM 603513). Following the ascertainment of a further branch of the CPSQ1 kindred, we found that the previously reported GAD1 variant did not segregate with the neurological disease phenotype in the recently ascertained branch of the kindred. Following genetic linkage studies to map autozygous regions and whole-exome sequencing, a missense variant (c.527 T > C; p. Leu176Pro, rs773333490) in the HPDL gene was detected and found to segregate with disease status in both branches of the kindred. HPDL encodes a 371-amino acid protein (4-Hydroxyphenylpyruvate Dioxygenase Like) that localizes to mitochondria but whose function is uncertain. Recently, biallelic loss of function variants and missense substitution-causing variants in HPDL were reported to cause a childhood onset progressive spastic movement disorder with a variable presentation. These findings suggest that HPDL-related neurological disease may mimic spastic cerebral palsy and that GAD1 should not be included in diagnostic gene panels for inherited cerebral palsy.

Developmental anomalies and associated impairments in Saudi children with cerebral palsy: a registry-based, multicenter study

Background

There are few epidemiological data to support rehabilitation programs for cerebral palsy (CP). Scarce international studies described the developmental anomalies (DAs) among children with CP. To our knowledge, the Arab countries did not publish data regarding this topic. This study aimed to describe the percentage of DAs among children with CP and detect the association between clinical subtypes and impairment severity in children with various DAs. We collected registry data of 679 children with cerebral palsy, between 2014 and 2019, from Armed Forces Hospitals, Taif, Kingdom of Saudi Arabia (KSA). We recorded demographic, perinatal, postnatal, developmental anomalies, subtypes, and impairment characteristics. We utilized the chi-square test to calculate the differences between groups.

Results

We reported significant differences between the children with and without anomalies regarding the percentages of consanguinity, preterm labor, low birth weight, and neonatal intensive care unit admission (P = 0.001, 0.002, 0.003, 0.005, respectively). Congenital dysplasia of the hip and hydrocephalus was the most frequent skeletal and nervous anomalies among children with DAs (19.1% and 12.8%, respectively). The spastic bilateral pattern was significantly higher among children with skeletal anomalies than the central nervous system/other groups (P < 0.001). The nervous anomalies group had higher frequencies of severe intellectual, motor, speech, and visual disabilities and a higher percentage of seizures than all other groups.

Conclusions

The frequency of children with anomalies in this study was comparable to previous studies. Children with CP and nervous system anomalies had more severe motor disabilities and associated impairments.