Associations between inherited thrombophilias, gestational age, and cerebral palsy

Genetic Predisposition to Adverse Neurodevelopmental Outcome of Extremely Low Birth Weight Infants

OBJECTIVE

This study aimed to evaluate whether there are genetic variants associated with adverse neurodevelopmental outcomes in extremely low birth weight (ELBW) infants.

STUDY DESIGN

We conducted a candidate gene association study in two well-defined cohorts of ELBW infants (<1,000 g). One cohort was for discovery and the other for replication. The discovery case-control analysis utilized anonymized DNA samples and evaluated 1,614 single-nucleotide polymorphisms (SNPs) in 145 genes concentrated in inflammation, angiogenesis, brain development, and oxidation pathways. Cases were children who died by age one or who were diagnosed with cerebral palsy (CP) or neurodevelopmental delay (Bayley II mental developmental index [MDI] or psychomotor developmental index [PDI] < 70) by 18 to 22 months. Controls were survivors with normal neurodevelopment. We assessed significant epidemiological variables and SNPs associated with the combined outcome of CP or death, CP, mental delay (MDI < 70) and motor delay (PDI < 70). Multivariable analyses adjusted for gestational age at birth, small for gestational age, sex, antenatal corticosteroids, multiple gestation, racial admixture, and multiple comparisons. SNPs associated with adverse neurodevelopmental outcomes with p < 0.01 were selected for validation in the replication cohort. Successful replication was defined as p < 0.05 in the replication cohort.

RESULTS

Of 1,013 infants analyzed (452 cases, 561 controls) in the discovery cohort, 917 were successfully genotyped for >90% of SNPs and passed quality metrics. After adjusting for covariates, 26 SNPs with p < 0.01 for one or more outcomes were selected for replication cohort validation, which included 362 infants (170 cases and 192 controls). A variant in SERPINE1, which encodes plasminogen activator inhibitor (PAI1), was associated with the combined outcome of CP or death in the discovery analysis (p = 4.1 × 10-4) and was significantly associated with CP or death in the replication cohort (adjusted odd ratio: 0.4; 95% confidence interval: 0.2-1.0; p = 0.039).

CONCLUSION

A genetic variant in SERPINE1, involved in inflammation and coagulation, is associated with CP or death among ELBW infants.

KEY POINTS

· Early preterm and ELBW infants have dramatically increased risks of CP and developmental delay.. · A genetic variant in SERPINE1 is associated with CP or death among ELBW infants.. · The SERPINE1 gene encodes the serine protease inhibitor plasminogen activator inhibitor..

The NESHIE and CP Genetics Resource (NCGR): A database of genes and variants reported in neonatal encephalopathy with suspected hypoxic ischemic encephalopathy (NESHIE) and consequential cerebral palsy (CP)

Neonatal encephalopathy (NE) with suspected hypoxic ischaemic encephalopathy (HIE) (NESHIE) is a complex syndrome occurring in newborns, characterised by altered neurological function. It has been suggested that genetic variants may influence NESHIE susceptibility and outcomes. Unlike NESHIE, for which a limited number of genetic studies have been performed, many studies have identified genetic variants associated with cerebral palsy (CP), which can develop from severe NESHIE. Identifying variants in patients with CP, as a consequence of NESHIE, may provide a starting point for the identification of genetic variants associated with NESHIE outcomes. We have constructed NCGR (NESHIE and CP Genetics Resource), a database of genes and variants reported in patients with NESHIE and CP (where relevant to NESHIE), for the purpose of collating and comparing genetic findings between the two conditions. In this paper we describe the construction and functionality of NCGR. Furthermore, we demonstrate how NCGR can be used to prioritise genes and variants of potential clinical relevance that may underlie a genetic predisposition to NESHIE and contribute to an understanding of its pathogenesis.

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-Trends in Epidemiology and Recent Development in Prenatal Mechanisms of Disease, Treatment, and Prevention

Cerebral palsy (CP) is the most common motor disability in childhood. This syndrome is the manifestation of intrauterine pathologies, intrapartum complications, and the postnatal sequel, especially among preterm neonates. A double hit model theory is proposed suggesting that an intrauterine condition along with intrapartum or postnatal insult lead to the development of CP. Recent reports demonstrated that treatment during the process of preterm birth such as magnesium sulfate and postnatal modalities such as cooling may prevent or reduce the prevalence of this syndrome. Moreover, animal models demonstrated that postnatal treatment with anti-inflammatory drugs coupled with nanoparticles may affect the course of the disease in pups with neuroinflammation. This review will describe the changes in the epidemiology of this disease, the underlying prenatal mechanisms, and possible treatments that may reduce the prevalence of CP and alter the course of the disease.

Pathogenesis, neuroimaging and management in children with cerebral palsy born preterm

With advances in obstetric and perinatal management, the incidence of intraventricular hemorrhage in premature infants has declined, while periventricular leukomalacia remains a significant concern. It is now known that brain injury in children born preterm also involves neuronal-axonal disease in supratentorial and infratentorial structures. The developing brain is especially vulnerable to white matter (WM) injury from 23 to 34 weeks gestation when blood vessels serving the periventricular WM are immature. Oligodendrocyte progenitors, which are beginning to form myelin during this time, are susceptible to attack from oxygen free radicals, glutamate, and inflammatory cytokines. Advances in imaging techniques such as diffusion tensor imaging provide a more complete picture of the location and extent of injury. Effective management of children born preterm with cerebral palsy is predicated on an understanding of sequential links from etiological antecedents to brain neuropathology as revealed with neuroimaging techniques to clinical phenotypes, toward focused interventions with measurable outcomes.

Litigations and the Obstetrician in Clinical Practice

The expectation of obstetrics is a perfect outcome. Obstetrics malpractice can cause morbidity and mortality that may engender litigation. Globally, increasing trend to litigation in obstetrics practice has resulted in high indemnity cost to the obstetrician with consequent frustration and overall danger to the future of obstetrics practice. The objective was to review litigations and the Obstetrician in Clinical Practice, highlighting medical ethics, federation of gynecology and obstetrics (FIGO's) ethical responsibility guideline on women's sexual and reproductive health and right; examine the relationship between medical ethics and medical laws; X-ray medical negligence and litigable obstetrics malpractices; and make recommendation towards the improvement of obstetrics practices to avert misconduct that would lead to litigation. Review involves a literature search on the internet in relevant journals, textbooks, and monographs. Knowledge and application of medical ethics are important to the obstetricians to avert medical negligence that will lead to litigation. A medical negligence can occur in any of the three triads of medicare viz: Diagnosis, advice/counseling, and treatment. Lawsuits in obstetrics generally center on errors of omission or commission especially in relation to the failure to perform caesarean section or to perform the operation early enough. Fear of litigation, high indemnity cost, and long working hours are among the main reasons given by obstetricians for ceasing obstetrics practice. Increasing global trend in litigation with high indemnity cost to the obstetrician is likely to jeopardize the future of obstetrics care especially in countries without medical insurance coverage for health practitioners. Litigation in obstetrics can be prevented through the Obstetrician's mindfulness of its possibility; acquainting themselves of the medical laws and guidelines related to their practice; ensuring adequate communication with, and consent of patients during treatment together with proper and correct documentation of cases. The supervision of resident-in-training, development and implementation of obstetrics protocol, and continuing medical education of obstetricians are also important factors to the prevention of litigation in obstetrics.

TNF-α and MTHFR Polymorphisms Associated with Cerebral Palsy in Chinese Infants

This study aims to examine whether the presence of polymorphisms in TNF-α (rs361525 and rs1799724) and MTHFR (rs1476413 and rs9651118) genes is associated with the pathogenesis of cerebral palsy (CP). A total of 105 CP patients and 114 age-, gender-, and ethnicity-matched healthy controls were genotyped for the selected polymorphisms, using TaqMan allelic discrimination assay. Odds ratios (OR) and 95 % confidence intervals (CI) were determined to measure the strength of associations of TNF-α and MTHFR polymorphisms with CP. The proportion of subjects with the gestational age more than 37 weeks or asphyxia was much larger in cases compared with controls (gestational age 63.8 vs. 34.2 %; asphyxia 25.7 vs. 7.9 %). The genotype frequencies of TNF-α rs1799724 were similar between groups (P > 0.05), yet the allele distributions were significantly different (P < 0.05). Both the allele and genotype distributions of MTHFR rs9651118 polymorphism varied significantly between the groups (P < 0.05). Subgroup analysis based on gestational age indicated a significant association between rs361525 and rs9651118 and CP with or without premature. TNF-α protein concentrations were significantly increased among patients with rs361525 GG genotype compared with controls. Also, a significant increase in the risk of CP was observed to be associated with the interactions of TNF-α rs1799724 and MTHFR rs9651118 (OR 2.75, 95 % CI 1.23-6.13). These data suggest that polymorphisms in TNF-α and MTHFR genes might be involved in the pathogenesis of CP in Chinese infants.

Association of Interleukin 6 gene polymorphisms with genetic susceptibilities to spastic tetraplegia in males: a case-control study

BACKGROUND

Cerebral palsy (CP) is a group of non-progressive motor impairment and permanent disorders causing limitation of activity and abnormal posture. It may be caused by infection (such as chorioamnionitis), asphyxia or multiple genetic factors. The Interleukin 6 gene (IL6) was suggested to be involved in the susceptibilities to CP risk as a kind of proinflammatory cytokine.

OBJECTIVE

To explore the genetic association between the polymorphisms of the IL6 gene and CP in the Chinese population.

METHODS

A total of 542 CP patients and 483 healthy control children were recruited in this study to detect five single nucleotide polymorphisms (rs1800796, rs2069837, rs2066992, rs2069840, and rs10242595) in the IL6 locus. Genotyping of SNPs was performed by the MassArray platform-based genotyping approach. The SHEsis program was applied to analyze the genotyping data.

RESULTS

Of the five selected SNPs, no significant allelic and genotypic association was found between CP patients and controls. However, subgroup analysis found significant differences in allele frequencies between spastic tetraplegia in males compared with controls at rs1800796 (OR=1.39, P=0.033, P=0.099 after SNPSpD correction) and rs2069837 (OR=1.58, P=0.012, P=0.035 after SNPSpD correction). The frequencies of the C allele of rs1800796 and the A allele of rs2069837 were greater in males with spastic tetraplegia than in the controls. The two SNPs haplotype rs1800796 (G) - rs2069837 (G) were also associated with a decreased risk of spastic tetraplegia in males (OR=0.619, P=0.009, P=0.027 after Bonferroni correction).

CONCLUSION

Genetic variation of the IL6 gene may influence susceptibility to spastic tetraplegia in males and its role in cerebral palsy deserves further evaluation in a large-scale and well-designed study.

Fetal and maternal candidate single nucleotide polymorphism associations with cerebral palsy: a case-control study

OBJECTIVE

Previous studies have suggested associations between certain genetic variants and susceptibility to cerebral palsy (CP). This study was designed to assess established and novel maternal and child genetic and epidemiologic risk factors for CP along with their interactions.

METHODS

DNA from 587 case and 1154 control mother-child pairs was analyzed. A panel of 35 candidate single nucleotide polymorphisms (SNPs) were examined and included SNPs in genes associated with (1) thrombophilia, (2) inflammation, and (3) risk factors for CP (eg, preterm birth). Comparisons were specified a priori and made by using a χ(2) test.

RESULTS

There were 40 fetal and 28 maternal associations with CP when analyzed by CP subtype, gestational age, genotypes of apolipoprotein E, and haplotypes of mannose-binding-lectin. After Bonferroni correction for multiple testing, no fetal or maternal candidate SNP was associated with CP or its subtypes. Only fetal carriage of prothrombin gene mutation remained marginally associated with hemiplegia in term infants born to mothers with a reported infection during pregnancy. Odds ratio directions of fetal SNP associations were compared with previously reported studies and confirmed no trend toward association.

CONCLUSIONS

Except for the prothrombin gene mutation, individual maternal and fetal SNPs in our candidate panel were not found to be associated with CP outcome. Past reported SNP associations with CP were not confirmed, possibly reflecting type I error from small numbers and multiple testing in the original reports.

Candidate genes and risk for CP: a population-based study

Studies suggest that genetic polymorphisms may increase an individual's susceptibility to CP. Most findings have yet to be corroborated in an independent cohort. This case-control study is nested within all 334,333 infants ≥36 wk gestation born at Kaiser Permanente Medical Care Program, 1991-2002. We included only non-Hispanic whites who had a neonatal blood sample available. Case patients (n = 138) were identified from medical records to have spastic or dyskinetic CP. Controls (n = 165) were randomly selected from the population. We genotyped polymorphisms previously associated with CP: inducible NOS (iNOS)-231, apolipoprotein E (apoE) ε2 and ε4 alleles, TNF-α-308, IL-8 -251, lymphotoxin 60, endothelial NOS -922, endothelial protein C receptor 219, mannose-binding lectin 54 and 52, factor V Leiden, methyltetrahydrofolate reductase 1298 and 667, prothrombin 20210, and platelet activator inhibitor 11053. Similar to previous reports, the iNOS-231 T allele (25.7 versus 18.9%, p = 0.04) and the apoE ε4 allele (19.3 versus 13.2%, p = 0.04) were more common in patients with CP than in controls. However, there was no statistically significant association between any genetic polymorphism and CP after correction for multiple comparisons.

The Australian cerebral palsy research study--protocol for a national collaborative study investigating genomic and clinical associations with cerebral palsy

AIM

Previous studies have proposed a link between the presence of specific single nucleotide polymorphisms (SNPs) and cerebral palsy and the majority of these associations remain to be confirmed or rejected by prospective studies with sufficient statistical power. Prior studies have also given little attention to the interaction of genomic characteristics and clinical risk factors.

METHODS

This paper describes the design of a prospective case-control study to test these genetic associations in conjunction with more stringent data collection in respect to clinical features associated with pregnancy, particularly maternal infection. Here we consider the ethical requirements, our hypothesis that genetic susceptibility modifies the risk of cerebral palsy in the presence of perinatal environmental triggers, a priori primary and secondary aims, power calculations, participant recruitment strategies, data linkage, sampling methods of genetic material and subsequent SNP analysis, collection of clinical data and the proposed final statistical analysis.

The association of genetic polymorphisms with cerebral palsy: a meta-analysis

AIM

The aim of our meta-analysis was to summarize quantitatively the association of genetic polymorphisms with cerebral palsy (CP).

METHOD

We identified 16 studies on the association of genetic polymorphisms with CP in Pubmed, Elsevier Science Direct, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, and Wanfang. Eleven of these studies (involving a total of 2533 cases and 4432 controls) were used in the current meta-analysis. A study was included if (1) it was published up to September 2010 and (2) it was a case-control study. We excluded one study of family members because the analysis was based on linkage considerations. Meta odds ratios and 95% confidence intervals based on fixed-effects models or random-effects models were dependent on Cochran's Q statistic. We examined the relationship between alleles, as well as genotypes and susceptibility to CP.

RESULTS

Meta-analysis was performed for 17 genetic polymorphisms: apolipoprotein E (ε2,ε3,ε4), methylenetetrahydrofolate reductase (MTHFR) (rs1801133), coagulation factor II (rs1799963]), coagulation factor V (rs6025), coagulation factor VII (rs5742910/rs6046), interleukin-6 (IL-6) (rs1800795), endothelial nitric oxide (rs1800779/rs1799983/rs3918226), fibrinogen β-polypeptide (rs1800790), plasminogen activator inhibitor 1 (rs1799768/rs7242), TNF-β lymphotoxin α precursor (rs1041981), adducin 1 (α) (rs4961), ADRB2 (rs1042714), and tumour necrosis factor α (rs1800629). We found a significant association between CP and IL-6 (rs1800795) [C vs G: odds ratio (OR) 1.79, 95% confidence interval (CI) 1.44-2.22, p<0.001; CC+GC vs GG: OR 1.72, 95% CI 1.29-2.29, p=0.002; CC vs GG+GC: OR 2.17, 95% CI 1.52-3.09, p<0.001], but no other genetic polymorphisms.

INTERPRETATION

This meta-analysis demonstrated that CP is associated with the genetic polymorphism IL-6 (rs1800795).

Fetal MBL2 haplotypes combined with viral exposure are associated with adverse pregnancy outcomes

OBJECTIVE

To investigate the roles of inherited polymorphisms in the MBL2 gene and exposure to viral infection in the development of a range of adverse pregnancy outcomes, including birthweight  < 10th percentile (small-for-gestational age, SGA), antepartum hemorrhage (APH), pregnancy-induced hypertensive disorders (PIHD), and preterm birth (PTB).

METHODS

This was a case-control study using DNA from newborn screening cards of 717 cases (babies with at least one of the adverse pregnancy outcomes listed above) and 609 controls, to screen for six polymorphisms within the MBL2 gene. These combine to create haplotypes with high (HYPA), intermediate (LYQA, LYPA), low (LXPA), and defective (HYPD, LYQC, LYPB) circulating MBL2 levels.

RESULTS

Significant associations were found between variant MBL2 haplotypes and SGA (LYPA  < 32 weeks OR 5.37, 95% CI 1.50-17.27), antepartum hemorrhage (LYPA  < 37 weeks OR 2.29, 95% CI 1.25-4.18), and PIHD (LYQC < 32 weeks (OR 17.89, 95% CI 2.20-139.57). Evidence of exposure to infection increased the effect of these associations, (SGA OR 17.00, 95% CI 1.03-252.48; APH OR 5.67, 95% CI 1.73-18.84; PIHD OR 23.80, 95% CI 1.08-1414.76), while no evidence of exposure to infection demonstrated no associations. PTB was significantly associated with the defective HYPD haplotype with evidence of exposure to infection (OR 6.14, 95% CI 1.21-29.89).

CONCLUSIONS

This research suggests that the combination of fetal MBL2 haplotypes and exposure to in utero viral infection increases the risk of adverse pregnancy outcomes, including PTB, antepartum hemorrhage, small-for-gestational age and PIHD.

Epidemiology of the cerebral palsies

Half of the most severe cases of cerebral palsy (CP) survive to adulthood, but because this longevity is relatively recent, there is no empirical experience of their life expectancy past middle age. The last 2 decades have seen significant developments in the management of persons with CP, involving specialist services from an increasing number of disciplines that require coordination to maximize their effectiveness. This article provides an overview of CP. The author discusses definitions of CP, its epidemiology, pathologies, and range of possible clinical descriptions, and briefly touches on management and prevention.

Association of fetal inflammation and coagulation pathway gene polymorphisms with neurodevelopmental delay at age 2 years

OBJECTIVE

The purpose of this study was to evaluate the association between fetal inflammation and coagulation gene single-nucleotide polymorphisms (SNPs) and neurodevelopmental delay at age 2 years.

STUDY DESIGN

We conducted a case-controlled secondary analysis of a randomized trial of single- vs multiple-course corticosteroids. Multiplex assay assessed 46 SNPs. Cases had mental developmental and/or psychomotor delay at age 2 years. Control subjects had normal neurodevelopment.

RESULTS

One hundred twenty-five cases and 147 control subjects were analyzed. Allele frequencies were different between cases and control subjects for interleukin (IL)1beta-511 (P = .009), IL4R-148 (P = .03), IL6-174 (P = .02), and IL6-176 (P = .007). Genotype frequencies were different for IL1beta-511 (P = .03) and IL6-174 (P = .04). Results for IL1beta-511, IL4R-148, and IL6-176 remained significant after logistic regression analysis. IL1beta-511 and IL6-176 minor alleles were associated with increased risk of neurodevelopmental delay (odds ratio, 3.1; 95% confidence interval [CI], 1.2-8.2 and 2.2; 95% CI, 1.2-3.9, respectively). IL4R-148 minor allele was protective (odds ratio, 0.6; 95% CI, 0.4-0.9).

CONCLUSION

Fetal SNPs in IL1beta, IL-4R, and IL-6 may be associated with neurodevelopmental delay at age 2 years.

Cerebral palsy in eastern Denmark: declining birth prevalence but increasing numbers of unilateral cerebral palsy in birth year period 1986-1998

The Cerebral Palsy Registry in eastern Denmark has been collecting cases using a uniform data sampling procedure since birth year 1979. Children are included by two child neurologists and an obstetrician. Information on pregnancy, birth, neonatal period, impairments and demographic data are registered. The total cerebral palsy birth prevalence has been significantly decreasing since the birth period 1983-1986 with 3.0 per 1000 live births until the period 1995-1998 with 2.1 per 1000 live births. The overall decrease was seen in preterm infants (<31 weeks) as well as in term infants and despite a simultaneous fall in perinatal and early neonatal mortality in the preterm group. Analysing the subtypes of CP we found a significant increase in the numbers as well as the rate of unilateral CP with a simultaneous fall in the numbers as well as the rate of bilateral CP. The explanation of this rise is not obvious. A change from bilateral periventricular lesions to unilateral is a possibility, but no major change in the neonatal handling could be documented. Regarding associated impairments, developmental delay/learning disabilities as well as motor function assessed by ability to walk (unassisted/assisted), both have changed toward higher percentage of children with unassisted walking and in need of special education.

[Cerebral palsy and perinatal asphyxia (I--diagnosis)]

Cerebral palsy (CP) is a group of disorders of the development of movement and posture, causing activity limitations, that are attributed to nonprogressing disturbances that occurred in the developing fetal or infant brain. The motor abnormalies are often accompanied by disturbances of sensation, perception, cognition, behavior and/or by a seizure disorder. The prevalence of CP has not decreased in developed countries over the past 30 years, despite the widespread use of electronic fetal heart rate monitoring and a 5- to 6-fold increase in the cesarean delivery rate. In the term newborn, CP may be attributed to perinatal asphyxia in case of metabolic acidosis in the cord blood (pH<7,00 and base deficit>12 mmol/L), followed by a moderate or severe neonatal encephalopathy within 24 hours and a further neurological impairement characterized by spastic quadriplegia and dyskinesia/dystonia. Dating the time of fetal asphyxia during delivery is possible when there are acute catastrophic complications during labor and unexpected acute or progressive fetal heart rate anomalies after a normal admission test, when there is a need for intensive neonatal resuscitation, a multi-organ failure within 72 hours of birth and visualization of acute non focal cerebral abnormalities, mainly by early magnetic resonance imaging (MRI). MRI sequences show either a brain-damaged pattern of the central basal ganglia, thalami and posterior limbs of internal capsules with relative cortical sparing, in acute, near-total asphyxial insults manifested by a continuous bradycardia or a pattern of cortical injury in the watershed zones and relative sparing of the central grey matter, in prolonged partial asphyxia, manifested by late or atypical variable decelerations with progressive fetal tachycardia, loss of reactivity and absent fluctuation. Prolongation of either type of asphyxial insult results in more global brain damage. In order to differentiate a CP occurring after perinatal asphyxia from other neurological sequelae in relation with infection, hemorrhage, stroke, malformations, genetic or metabolic diseases, it is essential that a definitive information from the brain by MRI and an extensive histological examination of the placenta are at disposal.

The genomic basis of cerebral palsy: a HuGE systematic literature review

Cerebral palsy has been associated with a number of candidate genes. To date, no systematic review has been conducted to synthesise genetic polymorphism associations with cerebral palsy. We apply the HuGE NET guidelines to search PubMed and EMBASE databases for publications investigating single nucleotide polymorphisms (SNPs) and cerebral palsy outcome. 22 papers were identified and are discussed in this review. Candidate genes were grouped as (1) thrombophilic, (2) cytokine, (3) apolipoprotein E or (4) other SNPs, largely related to cardiovascular physiology/pathophysiology and the functioning of the immune system. Of the studies identified, cohorts were usually small, without adequate control and ethnically diverse, making direct comparison between studies difficult. The most promising candidate genes include factor V Leiden, methylenetetrahydrofolate reductase, lymphotoxin-alpha, tumour necrosis factor-alpha, eNOS and mannose binding lectin. Large case-control studies are needed to confirm these candidates with attention given to cohort ethnicity, cerebral palsy subtype analysis and possible multiple gene and gene-environment interactions.

Candidate genes and cerebral palsy: a population-based study

OBJECTIVE

The objective of this study was to examine whether selected genetic polymorphisms in the infant are associated with later-diagnosed cerebral palsy.

METHODS

A population-based case-control study was conducted of 28 single-nucleotide polymorphisms measured in newborn screening blood spots. A total of 413 children with later-diagnosed cerebral palsy were born to white women in South Australia in 1986-1999, and there were 856 control children. Distributions of genotypic frequencies were examined in total cerebral palsy, in gestational age groups, and by types of cerebral palsy and gender. Genotyping was performed by using a TaqMan assay.

RESULTS

For inducible nitric-oxide synthase, possession of the T allele was more common in all children with cerebral palsy and for heterozygotes who were born at term. For lymphotoxin alpha, homozygous variant status was associated with risk for cerebral palsy and with spastic hemiplegic or quadriplegic cerebral palsy. Among term infants, heterozygosity for the endothelial protein C receptor single-nucleotide polymorphism was more frequent in children with cerebral palsy. In preterm infants, the variant A allele of interleukin 8 and heterozygosity for the beta-2 adrenergic receptor were associated with cerebral palsy risk. Interleukin 8 heterozygote status was associated with spastic diplegia. Variants of several genes were associated with cerebral palsy in girls but not in boys.

CONCLUSIONS

Two of the 28 single-nucleotide polymorphisms examined were associated with all types of spastic cerebral palsy in both gestational age groups and others with cerebral palsy in gestational age or cerebral palsy subgroups. Some of these associations support previous findings. There may be a genetic contribution to cerebral palsy risk, and additional investigation is warranted of genes and gene-environment interactions in cerebral palsy.

Association between Apolipoprotein E genotype and cerebral palsy is not confirmed in a Caucasian population

Apolipoprotein E (APOE) plays a significant role in lipid metabolism and has been implicated in the growth and repair of injured neurons. Two small studies have suggested an association between APOE genotype and cerebral palsy. We investigated if APOE genotype is associated with an increased risk for cerebral palsy, influences the type of cerebral palsy or interacts with prenatal viral infection to influence risk of cerebral palsy. The population-based case-control study comprised newborn screening cards of 443 Caucasian patients with cerebral palsy and 883 Caucasian matched controls. APOE genotyping was performed on DNA extracted from dried blood spots. Allelic and genotypic frequencies did not differ between cases and controls and combined frequencies were 0.10 (epsilon2), 0.76 (epsilon3), 0.14 (epsilon4), 0.03 (epsilon2/epsilon2), 0.10 (epsilon2/epsilon3), 0.03 (epsilon2/epsilon4), 0.02 (epsilon4/epsilon4), 0.21 (epsilon3/epsilon4), 0.61 (epsilon3/epsilon3). APOE genotype was correlated with cerebral palsy, type of cerebral palsy, gestation at birth and the presence of viral nucleic acids detected in previous work. Analysis by gestational age (all gestational ages, >/=37, 32-36 and <32 weeks) and type of cerebral palsy (all types, diplegia, hemiplegia and quadriplegia) showed no association between APOE genotype and cerebral palsy in this Caucasian population. An association between prenatal viral infection, APOE genotype and cerebral palsy was not demonstrated. These results did not confirm an association between APOE genotype, cerebral palsy, type of cerebral palsy and prenatal infection in a Caucasian population. Given the low frequency of APOE epsilon2 and some of the heterozygote and homozygote combinations in this study, a larger study is assessing this further.

Is cerebral palsy preventable?

PURPOSE OF REVIEW

To use evidence of good medical quality to update information on strategies for prevention of cerebral palsy, and on the success of these preventive efforts to date.

RECENT FINDINGS

Causes of cerebral palsy, and therefore promising approaches to prevention, differ by gestational age group and by clinical subtype. Neuroimaging and neuropathology indicate the importance of white matter disorders and of ischemic stroke in cerebral palsy; birth asphyxia, congenital malformations, placental pathology, and genetic variants also contribute to cerebral palsy risk. Multiplicity of risk factors markedly increases risk. Recent studies indicate that mild hypothermia lessens cerebral palsy risk in term infants with moderate neonatal encephalopathy, and the possibility that administration of magnesium sulphate to women in preterm labor may aid in primary prevention of cerebral palsy in very preterm infants.

SUMMARY

Past efforts to prevent cerebral palsy have not had the benefits sought, but recent results provide new hope and new challenges.

Fetal exposure to herpesviruses may be associated with pregnancy-induced hypertensive disorders and preterm birth in a Caucasian population

OBJECTIVE

To investigate the role of fetal viral infection in the development of a range of adverse pregnancy outcomes (APOs), including pregnancy-induced hypertensive disorders (PIHD), antepartum haemorrhage (APH), birthweight <10th percentile (small for gestational age, SGA) and preterm birth (PTB).

DESIGN

Population-based case-control study.

SETTING

Laboratory-based study.

POPULATION

The newborn screening cards of 717 adverse pregnancy cases and 609 controls.

METHODS

Newborn screening cards were tested for RNA from enteroviruses and DNA from herpesviruses using polymerase chain reaction (PCR). The herpesviruses were detected using two PCRs, one detecting nucleic acids from herpes simplex virus (HSV)-1, HSV-2, Epstein-Barr virus (EBV), cytomegalovirus (CMV) and human herpesvirus (HHV)-8, hereafter designated Herpes PCR group A viruses, and the other detecting nucleic acids from varicella-zoster virus (VZV), HHV-6 and HHV-7, hereafter designated Herpes PCR group B viruses.

MAIN OUTCOME MEASURE

Odds ratios and 95% CIs for specific APOs.

RESULTS

For both term and PTBs, the risk of developing PIHD was increased in the presence of DNA from Herpes PCR group B viruses (OR 3.57, 95% CI 1.10-11.70), CMV (OR 3.89, 95% CI 1.67-9.06), any herpesvirus (OR 5.70, 95% CI 1.85-17.57) and any virus (OR 5.17, 95% CI 1.68-15.94). The presence of CMV was associated with PTB (OR 1.61, 95% CI 1.14-2.27). No significant association was observed between SGA or APH and exposure to viral infection.

CONCLUSIONS

Fetal exposure to herpesvirus infection was associated with PIHD for both term and PTBs in this exploratory study. Exposure to CMV may also be associated with PTB. These findings need confirmation in future studies.

Space-Time Clustering Analyses of Occurrence of Cerebral Palsy in Northern England for Births 1991 to 2003

PURPOSE

The etiology of congenital cerebral palsy is unclear. Recent studies have suggested that maternal infection is involved. Indirect, but supportive, evidence for an infectious hypothesis would be provided by the finding of space-time clustering.

METHODS

We analyzed all 906 cases born during the period 1991-2003 using a population-based registry from Northern England. We applied the K-function method for testing global space-time clustering and used residential addresses at the time of birth. The Knox method was used to determine the spatio-temporal range over which global clustering occurred. Tests were repeated using nearest neighbor thresholds to allow for variable population density. Additionally, Kulldorff's scan statistic identified specific space-time clusters.

RESULTS

There was statistically significant evidence of global space-time clustering (p <or= 0.05). Clustering occurred over a range of close distances, but was most pronounced for cases born within 1-4 months of one another. A specific space-time cluster was identified during 1994.

CONCLUSIONS

The application of spatial statistics for the study of cerebral palsy is novel. There is tentative evidence for the involvement of spatially and temporally varying environmental etiological factors. These findings may support a role for infections or similar agents. However, the role of chance cannot be excluded.

Cerebral palsy and fetal inflammatory response syndrome: a review

Cerebral palsy (CP) is the most common cause of severe physical disability in childhood. The precise etiological factor for the development of the majority of cases of CP has not been identified, however, prematurity is considered to be the leading identifiable risk factor. During the last decade, intrauterine infection/inflammation has been identified as the most common cause of preterm delivery and neonatal complications. When microorganisms or their products gain access to the fetus they stimulate the production of cytokines and a systemic response termed FIRS (Fetal Inflammatory Response Syndrome). Subsequently, FIRS was implicated as a cause of fetal or neonatal injury that leads to CP and chronic lung disease. Several authors found an increase in the risk for CP in infants born to mothers with clinical chorioamnionitis, especially in preterm neonates. A relationship between CP and intra-amniotic inflammation was demonstrated, intrauterine infection may lead to activation of the cytokine network which in turn can cause white matter brain damage and preterm delivery, as well as the future development of CP. This white matter insult is identified clinically as periventricular leucomalacia (PVL) which is associated with the subsequent development of impaired neurological outcomes of variable severity including CP.

Thrombophilias, Perinatal Stroke, and Cerebral Palsy

Perinatal ischemic stroke has become recognized as a not-rare adverse outcome of pregnancy and a common cause of chronic neurologic disability in children. This review discusses the clinical entity, perinatal stroke, and its relationship to thrombophilias, inherited and acquired, and to maternal and pregnancy factors.

Neonatal seizure classification: a fetal perspective concerning childhood epilepsy

Neonatal seizures are markers for time-specific etiologies during antepartum, intrapartum and neonatal time periods. Seizures with or without encephalopathic signs can represent a continuum of maternal, placental, fetal and neonatal risk factors and disease states. A multi-dimensional classification scheme for neonatal seizures is suggested that will help strategize specific therapeutic interventions to optimize neurologic outcome and anticipate later neurological morbidities including epilepsy risk. This scheme combines "epileptic" and "non-epileptic" seizure descriptions which capture time-specific and brain region-specific mechanisms for seizures. Synchronized video electroencephalographic monitoring provides the most accurate start and endpoints for cortically generated seizures. However, subcortical sites of injury may also initiate abnormal clinical signs with or without the subsequent expression of electrographic seizures. Co-registration of digital neuroimaging techniques such as magnetic resonance imaging with computational electroencephalographic datasets will provide more precise structure-function correlates for neonatal seizures that address both cortical and subcortical sites of injury. Finally, more precise definitions of neonatal status epilepticus need to be established because of the long-term harmful effects on brain development by prolonged seizures expressed as epilepsy and cognitive-behavioral deficits. With this expanded classification scheme for neonatal seizures, novel pharmacologic and surgical strategies can be designed for disease-specific rescue, repair, and regeneration strategies of damaged brain tissue that occur during fetal and neonatal periods, and are later expressed during infancy and childhood. Clinical neuroscientists must strive to develop a classification scheme that bridges bench to bedside concepts of developmental neural plasticity research, recognizing both negative and positive consequences of brain remodeling and repair of the child and adolescent brain. Developmental neural plasticity also extends into adulthood when brain remodeling mechanisms further contribute to epileptogenesis and continues to impair quality of life.

Obstetric litigation is asphyxiating our maternity services

Obstetric care in the United States, as judged by maternal mortality, neonatal mortality, stillbirth rates, or any other metric, has never been better. Despite this, litigation over "bad outcomes" is threatening the specialty, not only now, but into the future. Despite damage to our specialty, the injured party often benefits little, if at all, from the process. Potential solutions include an emphasis on evidence-based medicine, a qualification and review process for medical experts, and a more rational and fair health court system.

Neurotropic viruses and cerebral palsy: population based case-control study

OBJECTIVE

To investigate the association between cerebral palsy and direct evidence for perinatal exposure to neurotropic viruses.

DESIGN

Population based case-control study.

SETTING

Adelaide Women's and Children's Hospital Research Laboratory.

PARTICIPANTS AND MAIN OUTCOME MEASURES

Newborn screening cards of 443 white case patients with cerebral palsy and 883 white controls were tested for viral nucleic acids from enteroviruses and herpes viruses by using polymerase chain reaction. Herpes group A viruses included herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpes virus 8 (HHV-8), and herpes group B viruses included varicella zoster virus (VZV) and human herpes viruses 6 and 7 (HHV-6 and HHV-7).

RESULTS

The prevalence of viral nucleic acids in the control population was high: 39.8% of controls tested positive, and the prevalence was highest in preterm babies. The detection of herpes group B viral nucleic acids increased the risk of developing cerebral palsy (odds ratio 1.68, 95% confidence interval 1.09 to 2.59).

CONCLUSIONS

Perinatal exposure to neurotropic viruses is associated with preterm delivery and cerebral palsy.