Congenital Anomalies in Children With Cerebral Palsy: A Systematic Review

Genetic pathways in cerebral palsy: a review of the implications for precision diagnosis and understanding disease mechanisms

ABSTRACT

Cerebral palsy is a diagnostic term utilized to describe a group of permanent disorders affecting movement and posture. Patients with cerebral palsy are often only capable of limited activity, resulting from non-progressive disturbances in the fetal or neonatal brain. These disturbances severely impact the child's daily life and impose a substantial economic burden on the family. Although cerebral palsy encompasses various brain injuries leading to similar clinical outcomes, the understanding of its etiological pathways remains incomplete owing to its complexity and heterogeneity. This review aims to summarize the current knowledge on the genetic factors influencing cerebral palsy development. It is now widely acknowledged that genetic mutations and alterations play a pivotal role in cerebral palsy development, which can be further influenced by environmental factors. Despite continuous research endeavors, the underlying factors contributing to cerebral palsy remain are still elusive. However, significant progress has been made in genetic research that has markedly enhanced our comprehension of the genetic factors underlying cerebral palsy development. Moreover, these genetic factors have been categorized based on the identified gene mutations in patients through clinical genotyping, including thrombosis, angiogenesis, mitochondrial and oxidative phosphorylation function, neuronal migration, and cellular autophagy. Furthermore, exploring targeted genotypes holds potential for precision treatment. In conclusion, advancements in genetic research have substantially improved our understanding of the genetic causes underlying cerebral palsy. These breakthroughs have the potential to pave the way for new treatments and therapies, consequently shaping the future of cerebral palsy research and its clinical management. The investigation of cerebral palsy genetics holds the potential to significantly advance treatments and management strategies. By elucidating the underlying cellular mechanisms, we can develop targeted interventions to optimize outcomes. A continued collaboration between researchers and clinicians is imperative to comprehensively unravel the intricate genetic etiology of cerebral palsy.

Neonatal well-being and timing of brain injury in persons with cerebral palsy born at term or late preterm

AIM

To describe the distribution of neuroimaging patterns in a term/late preterm population-based cohort with cerebral palsy (CP), ascertain associations between neuroimaging patterns and neonatal well-being, estimate the proportion with antenatal or perinatal timing of neuropathology, and apply this information to the understanding of common mechanisms of brain injury and causal pathways.

METHOD

The cohort for this observational study comprised 1348 persons born between 1999 and 2017 in Victoria, Australia. Using algorithms designed for the study, neonatal well-being and timing of brain injury were tabulated for the whole cohort and across neuroimaging patterns and birth epochs.

RESULTS

Clinical and demographic profiles, neonatal well-being, and timing of brain injury differed across neuroimaging patterns. An estimated 57% of the cohort had a complicated neonatal period. Timing of brain injury was antenatal in 57% and perinatal in 41%. A decrease in the relative proportions of perinatal timing of brain injury was observed over a period when the rates of CP in live births at term decreased.

INTERPRETATION

This study begins to bridge the knowledge gap about causation in CP, moving towards better description of the main mechanisms of brain injury and their contribution within CP cohorts, and facilitating the ability to monitor changes over time and the success of preventive measures.

WHAT THIS PAPER ADDS

In a population-based, term/late preterm cohort with cerebral palsy, 57% had a complicated neonatal period. In the same cohort, 57% had presumed antenatal timing of brain injury. The relative proportion with perinatal injury decreased over time.

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.

Severe Congenital Heart Defects and Cerebral Palsy

OBJECTIVE

To report the prevalence of cerebral palsy (CP) in children with severe congenital heart defects (sCHD) and the outcome/severity of the CP.

METHODS

Population-based, data linkage study between CP and congenital anomaly registers in Europe and Australia. The EUROCAT definition of severe CHD (sCHD) was used. Linked data from 4 regions in Europe and 2 in Australia were included. All children born in the regions from 1991 through 2009 diagnosed with CP and/or sCHD were included. Linkage was completed locally. Deidentified linked data were pooled for analyses.

RESULTS

The study sample included 4989 children with CP and 3684 children with sCHD. The total number of livebirths in the population was 1 734 612. The prevalence of CP was 2.9 per 1000 births (95% CI, 2.8-3.0) and the prevalence of sCHD was 2.1 per 1000 births (95% CI, 2.1-2.2). Of children with sCHD, 1.5% (n = 57) had a diagnosis of CP, of which 35 (61%) children had prenatally or perinatally acquired CP (resulting from a brain injury at ≤28 days of life) and 22 (39%) children had a postneonatal cause (a brain injury between 28 days and 2 years). Children with CP and sCHD more often had unilateral spastic CP and more intellectual impairments than children with CP without congenital anomalies.

CONCLUSIONS

In high-income countries, the proportion of children with CP is much higher in children with sCHD than in the background population. The severity of disease in children with CP and sCHD is milder compared with children with CP without congenital anomalies.

Congenital anomalies in children with postneonatally acquired cerebral palsy: an international data linkage study

AIM

To describe the major congenital anomalies present in children with postneonatally acquired cerebral palsy (CP), and to compare clinical outcomes and cause of postneonatally acquired CP between children with and without anomalies.

METHOD

Data were linked between total population CP and congenital anomaly registers in five European and three Australian regions for children born 1991 to 2009 (n=468 children with postneonatally acquired CP; 255 males, 213 females). Data were pooled and children classified into mutually exclusive categories based on type of congenital anomaly. The proportion of children with congenital anomalies was calculated. Clinical outcomes and cause of postneonatally acquired CP were compared between children with and without anomalies.

RESULTS

Major congenital anomalies were reported in 25.6% (95% confidence interval [CI] 21.7-29.9) of children with postneonatally acquired CP. Cardiac anomalies, often severe, were common and present in 14.5% of children with postneonatally acquired CP. Clinical outcomes were not more severe in children with congenital anomalies than those without anomalies. Cause of postneonatally acquired CP differed with the presence of congenital anomalies, with cerebrovascular accidents predominating in the anomaly group. Congenital anomalies were likely associated with cause of postneonatally acquired CP in 77% of children with anomalies.

INTERPRETATION

In this large, international study of children with postneonatally acquired CP, congenital anomalies (particularly cardiac anomalies) were common. Future research should determine specific causal pathways to postneonatally acquired CP that include congenital anomalies to identify opportunities for prevention.

WHAT THIS PAPER ADDS

One-quarter of children with postneonatally acquired cerebral palsy (CP) have a major congenital anomaly. Cardiac anomalies, often severe, are the most common anomalies. Causes of postneonatally acquired CP differ between children with and without congenital anomalies.

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).

Perinatal care with a view to preventing cerebral palsy

Birth prevalence of cerebral palsy (CP) is declining in high-income countries, to as low as 1.4 per 1000 live births in the most recent international reports. This represents a 35% reduction in birth prevalence over a 15-year period. This reduction is underpinned by a heightened focus of attention towards all aspects of CP, including: increased awareness, better data collection, development of national networks and registries, an explosion of research in basic science, perinatal care, neonatal neurology, public health, early detection, and targeted early intervention. Quick uptake of evidence into practice has ensued and overall improvements in clinical care occurred concurrently. It is anticipated that with continued partnerships with families, ongoing research driving further clinical improvement and vice versa, birth prevalence and severity of CP will further decline and the focus will shift to prevention in low- and middle-income countries. WHAT THIS PAPER ADDS: Research in the field of perinatal care and cerebral palsy (CP) prevention has increased significantly. In high-income countries, increased awareness of CP and scientific advances have improved clinical care. Population-based registers have limitations but remain the best mechanism to quantify birth prevalence of CP and accurately track trends. There have been recent reductions in the birth prevalence of CP.

Abnormal Head Size in Children and Adolescents with Congenital Nervous System Disorders or Neurological Syndromes with One or More Neurodysfunction Visible since Infancy

The current study was designed to investigate co-occurrence of absolute/relative microcephaly, absolute/relative macrocephaly and congenital nervous system disorders or neurological syndromes with symptoms visible since infancy, based on fundamental data acquired during the admission procedure at a neurological rehabilitation ward for children and adolescents. The study applied a retrospective analysis of data collected during the hospitalization of 327 children and adolescents, aged 4-18 years, affected since infancy by congenital disorders of the nervous system and/or neurological syndromes associated with a minimum of one neurodysfunction. To identify subjects with absolute/relative microcephaly, absolute/relative macrocephaly in the group of children and adolescents, the adopted criteria took into account z-score values for head circumference (z-score hc) and head circumference index (z-score HCI). Dysmorphological (x+/-3s) and traditional (x+/-2s) criteria were adopted to diagnose developmental disorders of head size. Regardless of the adopted criteria, absolute macrocephaly often coexists with state after surgery of lumbar myelomeningocele and hydrocephalus, isolated hydrocephalus, hereditary motor and sensory polyneuropathy, and Becker's muscular dystrophy (p < 0.001, p = 0.002). Absolute macrocephaly is often associated with neural tube defects and neuromuscular disorders (p = 0.001, p = 0.001). Relative microcephaly often occurs with non-progressive encephalopathy (p = 0.017, p = 0.029). Absolute microcephaly, diagnosed on the basis of traditional criteria, is often associated with epilepsy (p = 0.043). In children and adolescents with congenital nervous system disorders or neurological syndromes with one or more neurodysfunction visible since infancy, there is variation in abnormal head size (statistically significant relationships and clinical implications were established). The definitions used allowed for the differentiation of abnormal head size.