Congenital anomalies in cerebral palsy: where to from here?

Association between lower limb spasticity and cryptorchidism in males with cerebral palsy

AIM

To explore the association between presence and severity of lower limb spasticity (LLS) and risk of orchidopexy for cryptorchidism among people with cerebral palsy (CP) and to further define the cremasteric muscle spasticity theory.

METHOD

We queried the Pediatric Health Information System database for male patients with CP, stratified patients into those with/without LLS, and compared groups for orchidopexy occurrence. Comparative statistics were performed using χ2 and Mann-Whitney U tests for categorical and continuous variables respectively. The association between orchidopexy and spasticity type was investigated using logistic regression.

RESULTS

In total, 44 561 males with CP were identified. Of these, 1.6% underwent orchidopexy (median age: 7 years 8 months [interquartile range: 4 years 6 months-11 years 4 months]). LLS presence was significantly associated with higher orchidopexy rate compared to spasticity absence (odds ratio [OR] = 1.33 [1.10-1.59], p = 0.003). Among 7134 patients with LLS, intervention was significantly associated with higher orchidopexy rate (injection procedures: OR = 2.47 [2.27-6.39], p = 0.034; surgical procedure: OR = 2.60 [1.22-6.76], p = 0.026). LLS groin proximity was significantly associated with higher orchidopexy rate (OR = 2.52 [1.42-4.96], p = 0.003).

INTERPRETATION

A strong association exists between LLS presence and severity and orchidopexy risk among people with CP. These findings support a cremasteric spasticity hypothesis as an important factor of cryptorchidism in CP. Providers should continue to examine for cryptorchidism in males with CP as they age.

WHAT THIS PAPER ADDS

Lower limb spasticity (LLS) is associated with higher orchidopexy rate in cerebral palsy. Orchidopexy rate was higher in more severe LLS. Orchidopexy rate was higher in more proximal LLS.

Prevalence and temporal trends of cerebral palsy in children born from 2002 to 2017 in Ontario, Canada: Population-based cohort study

AIM

To examine the prevalence and temporal trends of cerebral palsy (CP) overall and by population characteristics.

METHOD

We identified 2 110 177 live births born in the province of Ontario, Canada, between 2002 and 2017 using administrative health data and estimated CP prevalence in children aged 0 to 16 years overall and by specific population characteristics. We also examined temporal trends in CP rates - overall and by characteristics - in young children (0-4 years) by their year of birth between 2002 and 2013 (n=1 587 087 live births) to allow for an equal follow-up time (4 years and 364 days) for all children.

RESULTS

Overall CP prevalence among children aged 0 to 16 years was 2.52 (95% confidence interval 2.45-2.59) per 1000 live births. CP rates in ages 0 to 4 years peaked at 2.86 in 2007 births, but steadily declined afterwards to 1.94 per 1000 live births in 2013. CP rates were higher in children born preterm, small for gestational age, males, multiples, children with congenital malformations, and in children of young (<20 years), old (≥40 years), primiparous, or grand multiparous (≥4) mothers; differences by these characteristics decreased over time. We observed socioeconomic disparities in CP rates that persisted over time.

INTERPRETATION

Despite the decreasing trend of CP rates overall, CP rates varied by the child and maternal characteristics over time.

WHAT THIS PAPER ADDS

Overall cerebral palsy (CP) prevalence was 2.5 per 1000 live births among children born from 2002 to 2017. CP prevalence peaked in children born in 2007 then steadily decreased between 2007 and 2013. Changes in CP rates varied over time by child and maternal characteristics. Socioeconomic inequalities in CP persisted and remained stable over the study period.

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.

Congenital anomalies in children with pre- or perinatally acquired cerebral palsy: an international data linkage study

AIM

To describe the frequency and types of major congenital anomalies present in children with pre- or perinatally acquired cerebral palsy (CP), and compare clinical outcomes for children with and without anomalies.

METHOD

This multi-centre total population collaborative study between Surveillance of Cerebral Palsy in Europe, Australian Cerebral Palsy Register, and European Surveillance of Congenital Anomalies (EUROCAT) involved six European and three Australian regions. Data were linked between each region's CP and congenital anomaly register for children born between 1991 and 2009, and then pooled. Children were classified into mutually exclusive categories based on type of anomaly. Proportions of children with congenital anomalies were calculated, and clinical outcomes compared between children with and without anomalies.

RESULTS

Of 8201 children with CP, 22.8% (95% confidence interval [CI] 21.9, 23.8) had a major congenital anomaly. Isolated cerebral anomalies were most common (45.2%), with a further 8.6% having both cerebral and non-cerebral anomalies. Cardiac anomalies only were described in 10.5% of children and anomalies associated with syndromes were also reported: genetic (8.0%), chromosomal (5.7%), and teratogenic (3.0%). Clinical outcomes were more severe for children with CP and congenital anomalies, particularly cerebral anomalies.

INTERPRETATION

This large, international study reports major congenital anomalies in nearly one-quarter of children with pre- or perinatally acquired CP. Future research must focus on aetiological pathways to CP that include specific patterns of congenital anomalies.

WHAT THIS PAPER ADDS

Congenital anomalies were reported in 23% of children with pre- or perinatally acquired cerebral palsy. A higher proportion of children born at or near term had anomalies. The most common type of anomalies were isolated cerebral anomalies. Clinical outcomes were more severe for children with congenital anomalies (particularly cerebral).

Mutations disrupting neuritogenesis genes confer risk for cerebral palsy

In addition to commonly associated environmental factors, genomic factors may cause cerebral palsy. We performed whole-exome sequencing of 250 parent-offspring trios, and observed enrichment of damaging de novo mutations in cerebral palsy cases. Eight genes had multiple damaging de novo mutations; of these, two (TUBA1A and CTNNB1) met genome-wide significance. We identified two novel monogenic etiologies, FBXO31 and RHOB, and showed that the RHOB mutation enhances active-state Rho effector binding while the FBXO31 mutation diminishes cyclin D levels. Candidate cerebral palsy risk genes overlapped with neurodevelopmental disorder genes. Network analyses identified enrichment of Rho GTPase, extracellular matrix, focal adhesion and cytoskeleton pathways. Cerebral palsy risk genes in enriched pathways were shown to regulate neuromotor function in a Drosophila reverse genetics screen. We estimate that 14% of cases could be attributed to an excess of damaging de novo or recessive variants. These findings provide evidence for genetically mediated dysregulation of early neuronal connectivity in cerebral palsy.

Congenital Malformations in Children With Cerebral Palsy: Is Prematurity Protective?

BACKGROUND

Congenital malformations are more common in children who are born prematurely, and prematurity is the leading risk factor for cerebral palsy. The primary objective of this study was to describe the profile of congenital malformations in a Canadian cohort of children with cerebral palsy. The secondary objectives were to compare the profiles of children with cerebral palsy with and without a congenital malformation and explore the possible role of prematurity.

METHODS

This retrospective cohort study utilized data from the Canadian Cerebral Palsy Registry, a population based registry of children with a confirmed diagnosis of cerebral palsy. Differences between groups were compared using Pearson's chi-square and Student t test as appropriate. Odds ratios and 95% confidence intervals were calculated RESULTS: Congenital malformations were present in 23% participants. In term-born children, brain malformations were the most common, whereas heart and gastrointestinal malformations were more common in children born prematurely. Children with a malformation had higher odds of being born at term (odds ratio 1.57, 95% confidence interval 1.20 to 2.04); having hypotonic, ataxic, or dyskinetic cerebral palsy (odds ratio 1.92, 95% confidence interval 1.35 to 2.72; being nonambulatory (odds ratio 1.70, 95% confidence interval 1.29 to 2.25); and having cerebral palsy-associated comorbidities.

CONCLUSIONS

One in four children with cerebral palsy have an associated congenital malformation. Their profile of term birth, higher Apgar scores, and lower frequency of perinatal seizures suggests a distinct causal pathway.

Congenital anomalies in children with cerebral palsy in rural Bangladesh

AIM

To determine the proportion of children with cerebral palsy (CP) who had major congenital anomalies, describe the types of disorders, and report on the children's functional outcomes.

METHOD

Data were extracted from the Bangladesh Cerebral Palsy Register (BCPR). Descriptive analyses were conducted on children with CP and major congenital anomalies. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to measure the association between major congenital anomalies, clinical severity, and presence of comorbidities.

RESULTS

Between January 2015 and December 2016, 726 children with CP were newly registered with the BCPR (277 females, 449 males; mean age [SD] at registration 90mo [54mo], 4mo-18y). Seventy-eight children (11%) had a major congenital anomaly. Neurological (86%) and musculoskeletal congenital anomalies (10%) were the most common. Microcephaly was the most common congenital anomaly (83%). The odds of severe functional motor limitations (OR=2.4, 95% CI=1.9-2.9), epilepsy (OR=1.6, 95% CI=1.1-2.1), visual impairment (OR=2.6, 95% CI=2.0-3.2), presence of strabismus (OR=3.9, 95% CI=3.8-4.4), hearing (OR=1.2, 95% CI=0.6-1.9), speech (OR=5.4, 95% CI=4.6-6.2), and intellectual impairments (OR=2.3, 95% CI=1.8-2.8) were higher in children with congenital anomalies compared to children without.

INTERPRETATION

The proportion of children with major congenital anomalies in the BCPR (11%) was lower than that identified in higher-income countries. This may be because of differences in how congenital anomalies are diagnosed as well as the impact of survival bias. In Bangladesh, children with CP and major congenital anomalies are more likely to have severe functional motor limitations and associated comorbidities.

WHAT THIS PAPER ADDS

Eleven per cent of children with cerebral palsy (CP) in Bangladesh had major congenital anomalies. Neurological and musculoskeletal congenital anomalies were the most common. Severe functional motor limitations and associated comorbidities were more common in children presenting with CP and major congenital anomalies.

Congenital Anomalies in Children With Cerebral Palsy: A Systematic Review

Congenital anomalies are a strong risk factor for cerebral palsy, particularly for children born at term. This systematic review aimed to address gaps in our understanding of the association between congenital anomalies and cerebral palsy. Eight population-based studies (n = 10 081) were identified. Congenital anomalies were reported in 12% to 32% of children with pre/perinatal brain injury and 20% of children with postneonatal brain injury. Variation between studies included study cohort inclusion criteria and the definitions and classification of included anomalies. The most common cerebral anomalies were microcephaly and hydrocephaly, whereas circulatory system anomalies were the most common noncerebral anomalies. The proportion of congenital anomalies was higher in children born at term than preterm. Synthesizing the highest quality data published, this review identified that congenital anomalies are common in cerebral palsy. New collaborative research, addressing sources of variation, is vital to identify pathways to cerebral palsy that include specific congenital anomalies, and explore opportunities for prevention.

Comprehensive investigation of congenital anomalies in cerebral palsy: protocol for a European-Australian population-based data linkage study (The Comprehensive CA-CP Study)

INTRODUCTION

Cerebral palsy (CP), an umbrella term for non-progressive conditions of cerebral origin resulting in motor impairments, is collectively the most common cause of physical disability in childhood. Cerebral and/or non-cerebral congenital anomalies are present in 15%-40% of children with CP. In order to identify effective prevention strategies for this substantial proportion of CP, a comprehensive understanding of the epidemiology of these congenital anomalies is required. International collaboration is needed, as previous attempts have fallen short due to a lack of power, since the anomalies are individually rare and CP comprises many clinical descriptions. The aim of this study is to generate new knowledge about the aetiologies of CP through a focused investigation into the role of congenital anomalies.

METHODS AND ANALYSIS

This collaborative, population-based data linkage study includes nine geographic regions (six in Europe, three in Australia) served by both congenital anomaly and CP registers. Register data for children with CP (both with and without congenital anomalies) and children with specific congenital anomalies (without CP) born between 1991 and 2009 will be linked and de-identified within each region. The resulting linked data sets will be quality assured, recoded, harmonised and then pooled into one data set. Analysis of the combined data set will include: frequencies/proportions of congenital anomalies and outcomes (type of CP, severity, impairments); descriptive analyses comparing timing of congenital anomaly development and brain injury/abnormality responsible for CP; ORs to calculate the odds of CP following a specific congenital anomaly; and identification of anomalies on causal pathways to CP.

ETHICS AND DISSEMINATION

Ethics approval for this collaborative study, The Comprehensive CA-CP Study, has been obtained from the Cerebral Palsy Alliance Human Research Ethics Committee (EC00402). Study findings will be disseminated at conferences and published in peer-reviewed journals, and recommendations will be made regarding the collection and classification of congenital anomaly data by CP registers.

Cryptorchidism in Boys With Cerebral Palsy Is Associated With the Severity of Disease and With Co-Occurrence of Other Congenital Anomalies

BACKGROUND

Cryptorchidism is reported in 40-50% of small case series of cerebral palsy (CP) and attributed to hypothalamic-pituitary-gonadal axis abnormalities, intellectual disability (ID), or cremaster spasticity. We collected demographic and clinical data to define the frequency of cryptorchidism and clinical comorbidities in a large CP population.

METHODS

Electronic health record data were collected for all male patients ≥7 years of age seen in a large, multidisciplinary CP clinic between 2000 and 2016. Variables including age, testicular position, surgical findings, CP severity, birth history, and comorbidities were tested for association using univariable and stepwise backward logistic regression analyses.

RESULTS

Of 839 established patients, testis position was scrotal in 553, undescended in 185 (24%), retractile in 38 (5%), and undocumented in 63 cases. Cryptorchidism were diagnosed at a mean age of 5.8 years, with 20% documented as acquired, and testes were most commonly in the superficial inguinal pouch (41%) and associated with an inguinal hernia (56%). Severity was bilateral in 114/166 (69%) undescended and 24/36 (66%) retractile cases, respectively. Mean birth weight and the frequency of prematurity (55, 58, and 54%) and multiple birth (14, 13, and 9%) were not significantly different among the three groups. We observed a strong ordinal trend in the frequency of comorbidities, including quadriplegia, syndromic features/known genetic disease, intrauterine growth restriction (IUGR), death, brain malformations, seizures, gastrostomy, absent continence, ID and hearing, speech or visual impairment, with the retractile group holding the intermediate position for the majority. The stepwise multivariable analysis showed independent positive associations of cryptorchidism with quadriplegia, syndromic features/known genetic disease, hearing loss, and absent continence, and inverse associations with gestational age and multiple birth.

CONCLUSION

These data suggest that cryptorchidism is less common than previously reported in CP cases, but most strongly associated with quadriplegia. Delayed diagnosis may be related to an acquired condition or to the multiple additional functional deficits that occur in this population. Our data suggest that UDT and CP may both be components of malformation syndromes occurring in singleton births whose clinical features are more likely to include earlier delivery, IUGR, hearing loss, and/or global spasticity.

A special supplement: findings from the Australian Cerebral Palsy Register, birth years 1993 to 2006

AIM

To briefly outline the strengths and limitations of cerebral palsy (CP) registers, and to report on findings of the Australian Cerebral Palsy Register (ACPR) pertaining to a population cohort of children with CP.

METHOD

De-identified data were extracted from the ACPR for people with CP in birth years 1993 to 2006, from South Australia, Victoria, and Western Australia. Live birth prevalence of CP was estimated and risk factors described.

RESULTS

The overall birth prevalence of CP (including those whose CP was postneonatally acquired) for the 1993 to 2006 birth cohort was 2.1 per 1000 live births (95% confidence interval [CI] 2.0-2.2). Excluding cases with a known postneonatal cause, the birth prevalence for pre/perinatally acquired CP was 2.0 per 1000 live births (95% CI 1.9-2.1). A downward trend in rates of CP in those born extremely preterm was evident over at least three consecutive periods across all three regions. Most (58.6%) children were born at term (≥ 37 wks). Male sex, early gestational age, low birthweight, and multiple birth were risk factors for CP.

INTERPRETATION

Overall rates of CP did not change during this period. The proportion of those with CP born extremely preterm decreased. The ACPR Group will investigate whether this pattern continues when data pertaining to the next birth cohort for all three regions becomes available.