Neuromonitoring in neonatal critical care part I: neonatal encephalopathy and neonates with possible seizures

The blooming of neonatal neurocritical care over the last decade reflects substantial advances in neuromonitoring and neuroprotection. The most commonly used brain monitoring tools in the neonatal intensive care unit (NICU) are amplitude integrated EEG (aEEG), full multichannel continuous EEG (cEEG), and near-infrared spectroscopy (NIRS). While some published guidelines address individual tools, there is no consensus on consistent, efficient, and beneficial use of these modalities in common NICU scenarios. This work reviews current evidence to assist decision making for best utilization of neuromonitoring modalities in neonates with encephalopathy or with possible seizures. Neuromonitoring approaches in extremely premature and critically ill neonates are discussed separately in the companion paper. IMPACT: Neuromonitoring techniques hold promise for improving neonatal care. For neonatal encephalopathy, aEEG can assist in screening for eligibility for therapeutic hypothermia, though should not be used to exclude otherwise eligible neonates. Continuous cEEG, aEEG and NIRS through rewarming can assist in prognostication. For neonates with possible seizures, cEEG is the gold standard for detection and diagnosis. If not available, aEEG as a screening tool is superior to clinical assessment alone. The use of seizure detection algorithms can help with timely seizures detection at the bedside.

Seizure Severity and Treatment Response in Newborn Infants with Seizures Attributed to Intracranial Hemorrhage

OBJECTIVE

We sought to characterize intracranial hemorrhage (ICH) as a seizure etiology in infants born term and preterm. For infants born term, we sought to compare seizure severity and treatment response for multisite vs single-site ICH and hypoxic-ischemic encephalopathy (HIE) with vs without ICH.

STUDY DESIGN

We studied 112 newborn infants with seizures attributed to ICH and 201 infants born at term with seizures attributed to HIE, using a cohort of consecutive infants with clinically diagnosed and/or electrographic seizures prospectively enrolled in the multicenter Neonatal Seizure Registry. We compared seizure severity and treatment response among infants with complicated ICH, defined as multisite vs single-site ICH and HIE with vs without ICH.

RESULTS

ICH was a more common seizure etiology in infants born preterm vs term (27% vs 10%, P < .001). Most infants had subclinical seizures (74%) and an incomplete response to initial antiseizure medication (ASM) (68%). In infants born term, multisite ICH was associated with more subclinical seizures than single-site ICH (93% vs 66%, P = .05) and an incomplete response to the initial ASM (100% vs 66%, P = .02). Status epilepticus was more common in HIE with ICH vs HIE alone (38% vs 17%, P = .05).

CONCLUSIONS

Seizure severity was greater and treatment response was lower among infants born term with complicated ICH. These data support the use of continuous video electroencephalogram monitoring to accurately detect seizures and a multistep treatment plan that considers early use of multiple ASMs, particularly with parenchymal and high-grade intraventricular hemorrhage and complicated ICH.

Characterization of Death in Infants With Neonatal Seizures

BACKGROUND

Neonatal seizures are associated with death and neurological morbidity; however, little is known about how neonates with seizures die.

METHODS

This was a prospective, observational cohort study of neonates with seizures treated at seven sites of the Neonatal Seizure Registry. We characterized the mode of death, evaluated the association between infant characteristics and mode of death, and evaluated predictors of death or transfer to hospice.

RESULTS

We enrolled 611 consecutive neonates with seizures, and 90 neonates (15%) died before hospital discharge at a median age of 11 days (range: 1 to 163 days); 32 (36%) died in the first postnatal week. An additional 19 neonates (3%) were transferred to hospice. The most common mode of in-hospital death was death after extubation amidst concerns for poor neurological prognosis, in the absence of life-threatening physiologic instability (n = 43, 48%). Only one infant died while actively receiving cardiopulmonary resuscitation. In an adjusted analysis, premature birth (odds ratio: 3.06, 95% confidence interval 1.59 to 5.90) and high seizure burden (odds ratio: 4.33, 95% confidence interval 1.88 to 9.95) were associated with increased odds of death or transfer to hospice.

CONCLUSION

In a cohort of neonates with seizures, death occurred predominantly after decisions to withdraw or withhold life-sustaining intervention(s). Future work should characterize how these decisions occur and develop optimized approaches to support families and clinicians caring for newborns with seizures.

Autism and developmental disability caused by KCNQ3 gain-of-function variants

OBJECTIVE

Recent reports have described single individuals with neurodevelopmental disability (NDD) harboring heterozygous KCNQ3 de novo variants (DNVs). We sought to assess whether pathogenic variants in KCNQ3 cause NDD and to elucidate the associated phenotype and molecular mechanisms.

METHODS

Patients with NDD and KCNQ3 DNVs were identified through an international collaboration. Phenotypes were characterized by clinical assessment, review of charts, electroencephalographic (EEG) recordings, and parental interview. Functional consequences of variants were analyzed in vitro by patch-clamp recording.

RESULTS

Eleven patients were assessed. They had recurrent heterozygous DNVs in KCNQ3 affecting residues R230 (R230C, R230H, R230S) and R227 (R227Q). All patients exhibited global developmental delay within the first 2 years of life. Most (8/11, 73%) were nonverbal or had a few words only. All patients had autistic features, and autism spectrum disorder (ASD) was diagnosed in 5 of 11 (45%). EEGs performed before 10 years of age revealed frequent sleep-activated multifocal epileptiform discharges in 8 of 11 (73%). For 6 of 9 (67%) recorded between 1.5 and 6 years of age, spikes became near-continuous during sleep. Interestingly, most patients (9/11, 82%) did not have seizures, and no patient had seizures in the neonatal period. Voltage-clamp recordings of the mutant KCNQ3 channels revealed gain-of-function (GoF) effects.

INTERPRETATION

Specific GoF variants in KCNQ3 cause NDD, ASD, and abundant sleep-activated spikes. This new phenotype contrasts both with self-limited neonatal epilepsy due to KCNQ3 partial loss of function, and with the neonatal or infantile onset epileptic encephalopathies due to KCNQ2 GoF. ANN NEUROL 2019;86:181-192.

Seizures in Preterm Neonates: A Multicenter Observational Cohort Study

BACKGROUND

The purpose of this study was to characterize seizures among preterm neonates enrolled in the Neonatal Seizure Registry, a prospective cohort of consecutive neonates with seizures at seven pediatric centers that follow the American Clinical Neurophysiology Society's neonatal electroencephalography monitoring guideline.

STUDY DESIGN

Of 611 enrolled neonates with seizures, 92 (15%) were born preterm. Seizure characteristics were evaluated by gestational age at birth for extremely preterm (<28 weeks, N = 18), very preterm (28 to <32 weeks, N = 18), and moderate to late preterm (32 to <37 weeks, N = 56) and compared with term neonates.

RESULTS

Hypoxic-ischemic encephalopathy (33%) and intracranial hemorrhage (27%) accounted for the etiology in more than half of preterm neonates. Hypothermia therapy was utilized in 15 moderate to late preterm subjects with encephalopathy. The presence of subclinical seizures, monotherapy treatment failure, and distribution of seizure burden (including status epilepticus) was similar in preterm and term neonates. However, exclusively subclinical seizures occurred more often in preterm than term neonates (24% vs 14%). Phenobarbital was the most common initial medication for all gestational age groups, and failure to respond to an initial loading dose was 63% in both preterm and term neonates. Mortality was similar among the three preterm gestational age groups; however, preterm mortality was more than twice that of term infants (35% vs 15%).

CONCLUSIONS

Subclinical seizures were more common and mortality was higher for preterm than term neonates. These data underscore the importance of electroencephalographic monitoring and the potential for improved management in preterm neonates.

Treatment Duration After Acute Symptomatic Seizures in Neonates: A Multicenter Cohort Study

We aimed to define determinants of duration of treatment for acute symptomatic neonatal seizures in a contemporary multicenter observational cohort study. After adjustment for potential confounders, only study site and seizure etiology remained significantly associated with the chance of continuing antiseizure medication after discharge to home.

Contemporary Profile of Seizures in Neonates: A Prospective Cohort Study

OBJECTIVE

To determine the contemporary etiology, burden, and short-term outcomes of seizures in neonates monitored with continuous video-electroencephalogram (cEEG).

STUDY DESIGN

We prospectively collected data from 426 consecutive neonates (56% male, 88% term) ≤44 weeks' postmenstrual age with clinically suspected seizures and/or electrographic seizures. Subjects were assessed between January 2013 and April 2015 at 7 US tertiary care pediatric centers following the guidelines of the American Clinical Neurophysiology Society for cEEG for at-risk neonates. Seizure etiology, burden, management, and outcome were determined by chart review by the use of a case report form designed at study onset.

RESULTS

The most common seizure etiologies were hypoxic-ischemic encephalopathy (38%), ischemic stroke (18%), and intracranial hemorrhage (11%). Seizure burden was high, with 59% having ≥7 electrographic seizures and 16% having status epilepticus; 52% received ≥2 antiseizure medications. During the neonatal admission, 17% died; 49% of survivors had abnormal neurologic examination at hospital discharge. In an adjusted analysis, high seizure burden was a significant risk factor for mortality, length of hospital stay, and abnormal neurological examination at discharge.

CONCLUSIONS

In this large contemporary profile of consecutively enrolled newborns with seizures treated at centers that use cEEG per the guidelines of the American Clinical Neurophysiology Society, about one-half had high seizure burden, received ≥2 antiseizure medications, and/or died or had abnormal examination at discharge. Greater seizure burden was associated with increased morbidity and mortality. These findings underscore the importance of accurate determination of neonatal seizure frequency and etiology and a potential for improved outcome if seizure burden is reduced.

Video-EEG monitoring in newborns with hypoxic-ischemic encephalopathy treated with hypothermia

BACKGROUND

Therapeutic hypothermia (TH) is becoming standard of care in newborns with hypoxic-ischemic encephalopathy (HIE). The prognostic value of the EEG and the incidence of seizures during TH are uncertain.

OBJECTIVE

To describe evolution of EEG background and incidence of seizures during TH, and to identify EEG patterns predictive for MRI brain injury.

METHODS

A total of 41 newborns with HIE underwent TH. Continuous video-EEG was performed during hypothermia and rewarming. EEG background and seizures were reported in a standardized manner. Newborns underwent MRI after rewarming. Sensitivity and specificity of EEG background for moderate to severe MRI brain injury was assessed at 6-hour intervals during TH and rewarming.

RESULTS

EEG background improved in 49%, remained the same in 38%, and worsened in 13%. A normal EEG had a specificity of 100% upon initiation of monitoring and 93% at later time points. Burst suppression and extremely low voltage patterns held the greatest prognostic value only after 24 hours of monitoring, with a specificity of 81% at the beginning of cooling and 100% at later time points. A discontinuous pattern was not associated with adverse outcome in most patients (73%). Electrographic seizures occurred in 34% (14/41), and 10% (4/41) developed status epilepticus. Seizures had a clinical correlate in 57% (8/14) and were subclinical in 43% (6/14).

CONCLUSIONS

Continuous video-EEG monitoring in newborns with HIE undergoing TH provides prognostic information about early MRI outcome and accurately identifies electrographic seizures, nearly half of which are subclinical.

Dorsal brain stem syndrome: MR imaging location of brain stem tegmental lesions in neonates with oral motor dysfunction

The anatomic extent of brain stem damage may provide information about clinical outcome and prognosis in children with hypoxic-ischemic encephalopathy and oral motor dysfunction. The aim of this study was to retrospectively characterize the location and extent of brain stem lesions in children with oral motor dysfunction. From January 2005 to August 2009, 43 infants hospitalized at our institution were included in the study because of a history of hypoxic-ischemic events. Of this group, 14 patients showed oral motor dysfunction and brain stem tegmental lesions detected at MR imaging. MR imaging showed hypoxic-ischemic lesions in supra- and infratentorial areas. Six of 14 patients revealed only infratentorial lesions. Focal symmetric lesions of the tegmental brain stem were always present. The lesions appeared hyperintense on T2-weighted images and hypointense on IR images. We found a strong association (P < .0001) between oral motor dysfunction and infratentorial lesions on MR imaging. Oral motor dysfunction was associated with brain stem tegmental lesions in posthypoxic-ischemic infants. The MR imaging examination should be directed to the brain stem, especially when a condition of prolonged gavage feeding is necessary in infants.

Congenital central hypoventilation syndrome: genotype-phenotype correlation in parents of affected children carrying a PHOX2B expansion mutation

Congenital Central Hypoventilation Syndrome (CCHS) is a rare genetic disorder. Although most CCHS associated PHOX2B mutations occur de novo, about 10% of the cases are inherited from apparently asymptomatic parents, thus confirming variable expressivity and incomplete penetrance of PHOX2B mutations. Three asymptomatic parents of children affected with CCHS, and found to carry the same PHOX2B expansion mutations as their siblings, were studied by overnight polysomnography and somatic mosaicism analysis. In one case, significant sleep breathing control anomalies were detected, while the other two resulted in normal. In tissue-specific allele studies, mosaicism with a comparatively low mutant allele proportion was showed in the two unaffected adult carriers. Accurate polysomnography and assessment of the degree of somatic mosaicism should be conducted in asymptomatic carriers of PHOX2B mutations, as they may unmask subclinical but significant anomalies.

Expanding CEP290 mutational spectrum in ciliopathies

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.

Cryptic chromosome deletions involving SCN1A in severe myoclonic epilepsy of infancy

OBJECTIVE

To identify cryptic chromosomal deletions involving SCN1A in patients with severe myoclonic epilepsy of infancy (SMEI).

METHODS

Thirty-nine patients with SMEI and without SCN1A point mutations and their parents were typed with 14 intragenic SCN1A polymorphisms to identify hemizygosity. The parental origin and the extent of genomic deletions were determined by fluorescence in situ hybridization analysis using genomic clones encompassing chromosome 2q24.3-q31.1. Deletion breakpoints were more finely mapped by typing single-nucleotide polymorphisms and microsatellite markers.

RESULTS

We identified three patients with SMEI who had genomic deletions encompassing the SCN1A locus. Deletion size was between 607 kb and 4.7 Mb. Deletions originated de novo from paternal chromosome in all subjects. One patient had central precocious puberty and palatoschisis. Genotype-phenotype correlations suggest that these clinical features are due to genes centromeric to SCN1A.

CONCLUSIONS

Patients with severe myoclonic epilepsy of infancy (SMEI) lacking SCN1A point mutations should be investigated for cryptic chromosomal deletions involving SCN1A. Clinical features other than epilepsy could be associated with SMEI as a consequence of deletions in contiguous genes.

Timing of cognitive deficits following neonatal seizures: relationship to histological changes in the hippocampus

Neonatal seizures are frequently associated with cognitive impairment and reduced seizure threshold. Previous studies in our laboratory have demonstrated that rats with recurrent neonatal seizures have impaired learning, lower seizure thresholds, and sprouting of mossy fibers in CA3 and the supragranular region of the dentate gyrus in the hippocampus when studied as adults. The goal of this study was to determine the age of onset of cognitive dysfunction and alterations in seizure susceptibility in rats subjected to recurrent neonatal seizures and the relation of this cognitive impairment to mossy fiber sprouting and expression of glutamate receptors. Starting at postnatal day (P) 0, rats were exposed to 45 flurothyl-induced seizures over a 9-day period of time. Visual-spatial learning in the water maze and seizure susceptibility were assessed in subsets of the rats at P20 or P35. Brains were evaluated for cell loss, mossy fiber distribution, and AMPA (GluR1) and NMDA (NMDAR1) subreceptor expression at these same time points. Rats with neonatal seizures showed significant impairment in the performance of the water maze and increased seizure susceptibility at both P20 and P35. Sprouting of mossy fibers into the CA3 and supragranular region of the dentate gyrus was seen at both P20 and P35. GluR1 expression was increased in CA3 at P20 and NMDAR1 was increased in expression in CA3 and the supragranular region of the dentate gyrus at P35. Our findings indicate that altered seizure susceptibility and cognitive impairment occurs prior to weaning following a series of neonatal seizures. Furthermore, these alterations in cognition and seizure susceptibility are paralleled by sprouting of mossy fibers and increased expression of glutamate receptors. To be effective, our results suggest that strategies to alter the adverse outcome following neonatal seizures will have to be initiated during, or shortly following, the seizures.

The long-term use of felbamate in children with severe refractory epilepsy

The aim of the study was to assess the efficacy and safety of felbamate (FBM) as add-on therapy in pediatric patients with severe uncontrolled seizures during a 3-year follow-up. Thirty-six patients were enrolled between February 1994 and February 1997. Patients suffered from partial epilepsy (n=13), Lennox-Gastaut syndrome (LGS) (n=9), infantile spasms (IS) n=8 or other forms of generalized epilepsy (n=6). FBM was titrated weekly from 15 up to 45 mg/kg. By February 1995, all patients had hematological and biochemical monitoring prior to FBM therapy and every 15 days during the study. The results achieved at different treatment durations were analyzed. Overall efficacy measured as > or =50% reduction in seizure frequency varied during follow-up: 69% at 3 months, progressively decreasing to 66% at 6 months, to 47% at 1 year and 41% of the initial cohort at the end of the study. Most frequent side effects were anorexia, weight loss, urinary retention, somnolence, nervousness and insomnia. FBM controlled a broad spectrum of otherwise refractory seizures. Best results were obtained against simple partial seizures with or without secondary generalization, tonic and atonic seizures. A substantial improvement in seizure control was maintained in one-third of the patients for at least 3 years.

hGFRalpha-4: a new member of the GDNF receptor family and a candidate for NBIA

Hallervorden-Spatz syndrome (neurodegeneration with brain iron accumulation type 1; OMIM entry 234200) is a rare inherited neurodegenerative disease. In this article, evidence for a newly identified gene as a candidate for Hallervorden-Spatz syndrome is given. Previously Hallervorden-Spatz syndrome was mapped to a 4-cm region in 20p12.3-13. During positional cloning efforts a new member of the glial-derived neurotrophic factor receptor family was discovered in this region. Like other members of this receptor family, this new gene is predicted to be secreted and glycosyl-phosphatidylinositol linked, and it maintains conserved cysteine residues. However, cDNA and genomic studies in both humans and mice indicate that this gene lacks the sequence corresponding to exons 2 and 3 in other family members. In situ hybridization reveals that it is expressed primarily in the brain and bladder in the embryonic mouse. Mutation analysis of patients with Hallervorden-Spatz syndrome revealed two potentially significant amino acid changes in two patients but failed to identify mutations in the remaining 10 subjects. The implication of these findings for the relationship between this gene and Hallervorden-Spatz syndrome is discussed.

Reduced neurogenesis after neonatal seizures

Although neonatal seizures are quite common, there is controversy regarding their consequences. Despite considerable evidence that seizures may cause less cell loss in young animals compared with mature animals, there are nonetheless clear indications that seizures may have other potentially deleterious effects. Because it is known that seizures in the mature brain can increase neurogenesis in the hippocampus, we studied the extent of neurogenesis in the granule cell layer of the dentate gyrus over multiple time points after a series of 25 flurothyl-induced seizures administered between postnatal day 0 (P0) and P4. Rats with neonatal seizures had a significant reduction in the number of the thymidine analog 5-bromo-2'-deoxyuridine-5'-monophosphate- (BrdU) labeled cells in the dentate gyrus and hilus compared with the control groups when the animals were killed either 36 hr or 2 weeks after the BrdU injections. The reduction in BrdU-labeled cells continued for 6 d after the last seizure. BrdU-labeled cells primarily colocalized with the neuronal marker neuron-specific nuclear protein and rarely colocalized with the glial cell marker glial fibrillary acidic protein, providing evidence that a very large percentage of the newly formed cells were neurons. Immature rats subjected to a single seizure did not differ from controls in number of BrdU-labeled cells. In comparison, adult rats undergoing a series of 25 flurothyl-induced seizures had a significant increase in neurogenesis compared with controls. This study indicates that, after recurrent seizures in the neonatal rat, there is a reduction in newly born granule cells.

Anticonvulsant action and long-term effects of gabapentin in the immature brain

The anticonvulsant action and the long-term effects on learning, memory and behavior of the new generation antiepileptic drug gabapentin (GBP) were investigated in immature animals. Kainic acid (KA) was administered to rats on postnatal day (P) 35. Animals were treated with GBP or saline from P36 to P75 and spontaneous seizure frequency was monitored. After tapering the drug, the rats were tested in the water maze and open field test. Brains were then analyzed for histological lesions. Animals treated with GBP following KA-induced status epilepticus had a reduced incidence of spontaneous recurrent seizures, a better pathology score, and less aggressiveness compared to saline-treated controls. Effectiveness of GBP on seizure threshold was tested using flurothyl inhalation in 10 separate age groups of animals ranging from the newborn period to adulthood. Furthermore, GBP plasma concentration peaks were determined in all age groups. At all ages, GBP pre-treated animals demonstrated a higher seizure threshold. Plasma GBP concentrations did not significantly change with age. These data suggest that acute administration of a single therapeutic dose of GBP increases the seizure threshold at all ages studied, while chronic treatment following the status reduces spontaneous seizure frequency and cell damage and has no long-term adverse consequences on cognitive processes during development.

Timing of ketogenic diet initiation in an experimental epilepsy model

Following kainic acid (KA)-induced status epilepticus (SE), the ketogenic diet (KD) retards the development of epileptogenesis, with fewer spontaneous recurrent seizures (SRS) and less mossy fiber sprouting than rats on a normal diet. In this study, we investigated whether there is a critical period for initiation of the KD, in terms of the diet's effectiveness in reducing SRS. In addition, we investigated whether early treatment with the KD prevents the deficits in spatial learning and memory that ordinarily follow KA-induced SE. Young rats (P30) underwent KA-induced SE, followed by assignment to one of three treatment groups: control diet ('KA'), KD begun 2 days after SE ('KD2'), and KD begun fourteen days after SE ('KD14'). For 12 weeks following SE, rats were monitored by closed circuit video recording (12 h/wk) to detect SRS. KD2 rats had significantly fewer SRS than rats in the control or KD14 groups. On water maze testing to assess spatial learning and memory, KD2 rats had significantly poorer acquisition of place learning than control (KA alone) or KD14 rats. KD2 rats also failed to gain weight well. There was no difference between groups on routine histologic examination of the hippocampus. In summary, P30 rats placed on the KD 2 days after SE were relatively protected from recurrent seizures, but showed behavioral and physical impairment. Rats placed on the KD 14 days after KA-induced SE did not differ from controls with regard to spontaneous seizure rate.

Long-term effects of neonatal seizures: a behavioral, electrophysiological, and histological study

Previous studies have demonstrated that recurrent seizures during the neonatal period lead to permanent changes in seizure threshold and learning and memory. The pathophysiological mechanisms for these changes are not clear. To determine if neonatal seizures cause changes in hippocampal excitability or inhibition, we subjected rats to 50 flurothyl-induced seizures during the first 10 days of life (five seizures per day). When the rats were adults, we examined seizure threshold using flurothyl inhalation, and learning and memory in the water maze. In separate groups of animals, we evaluated in vivo paired-pulse facilitation and inhibition in either CA1 with stimulation of the Schaffer collaterals or dentate gyrus with stimulation of the perforant path. Following these studies, the animals were sacrificed and the brains evaluated for mossy fiber sprouting with the Timm stain. Compared to control animals, rats with 50 flurothyl seizures had a reduced seizure threshold, impaired learning and memory in the water maze, and sprouting of mossy fibers in the CA3 pyramidal cell layer and molecular layer of the dentate gyrus. No significant differences in impaired paired-pulse inhibition was noted between the flurothyl-treated and control rats. This study demonstrates that recurrent neonatal seizures result in changes of neuronal connectivity and alterations in seizure susceptibility, learning and memory. However, the degree of impairment following 50 seizures was modest, demonstrating that the immature brain is remarkably resilient to seizure-induced damage.

Mendelian diseases among Roman Jews: implications for the origins of disease alleles

The Roman Jewish community has been historically continuous in Rome since pre-Christian times and may have been progenitor to the Ashkenazi Jewish community. Despite a history of endogamy over the past 2000 yr, the historical record suggests that there was admixture with Ashkenazi and Sephardic Jews during the Middle Ages. To determine whether Roman and Ashkenazi Jews shared common signature mutations, we tested a group of 107 Roman Jews, representing 176 haploid sets of chromosomes. No mutations were found for Bloom syndrome, BRCA1, BRCA2, Canavan disease, Fanconi anemia complementation group C, or Tay-Sachs disease. Two unrelated individuals were positive for the 3849 + 10C->T cystic fibrosis mutation; one carried the N370S Gaucher disease mutation, and one carried the connexin 26 167delT mutation. Each of these was shown to be associated with the same haplotype of tightly linked microsatellite markers as that found among Ashkenazi Jews. In addition, 14 individuals had mutations in the familial Mediterranean fever gene and three unrelated individuals carried the factor XI type III mutation previously observed exclusively among Ashkenazi Jews. These findings suggest that the Gaucher, connexin 26, and familial Mediterranean fever mutations are over 2000 yr old, that the cystic fibrosis 3849 + 10kb C->T and factor XI type III mutations had a common origin in Ashkenazi and Roman Jews, and that other mutations prevalent among Ashkenazi Jews are of more recent origin.

Familial spastic paraplegia, axonal sensory-motor polyneuropathy and bulbar amyotrophy with facial dysmorphia: new cases of Troyer-like syndrome

We studied two Libyan siblings, born to healthy consanguineous parents, who had suffered from a progressive neurological disorder, characterized by facial dysmorphia, ataxia, spastic paraplegia and an axonal sensory-motor polyneuropathy, since the age of 3 years. The clinical picture progressed slowly over a 6-year period to involve also bulbar and distal limb muscles. Interestingly, we found unusual tubulofilamentous inclusions in peripheral nerves and presynaptic buttons at the neuromuscular junctions. Describing the clinical picture of this presumably new disorder, we comment on the difference from similar conditions.

Vigabatrin versus ACTH as first-line treatment for infantile spasms: a randomized, prospective study

PURPOSE

To compare the efficacy and tolerability of vigabatrin (VGB) and adrenocorticotrophic hormone (ACTH) as first-line therapy in infantile spasms.

METHODS

Forty-two infants (22 males, 20 females) aged 2-9 months with newly diagnosed infantile spasms, were included in the trial. Patients were randomized to receive VGB 100-150 mg/kg/day or Depot ACTH 10 IU/day. The alternative drug was given if spasms were not controlled within 20 days or in cases of intolerance to initial therapy. Twenty-three patients (7 cryptogenic, 16 symptomatic) received VGB as first-line therapy; 19 patients (8 cryptogenic, 11 symptomatic) received ACTH as the first drug.

RESULTS

Cessation of spasms was observed in 11 (48%) of the patients randomized to VGB and in 14 (74%) of those randomized to ACTH. Response to VGB was observed within 1-14 days, but two-thirds of patients (7/11) responded within 3 days. In the group treated with VGB, side effects such as drowsiness, hypotonia and irritability were observed in 13% of patients, compared with 37% in the group treated with ACTH. VGB was more effective than ACTH as treatment for cerebral malformations or tuberous sclerosis, whereas ACTH proved more effective in perinatal hypoxic/ischemic injury. The efficacy of the two drugs was similar in cryptogenic cases. Disappearance of interictal EEG abnormalities occurred sooner in patients randomized to ACTH than in those who received VGB as initial therapy. During the second phase, the alternative drug was given to the resistant patients. Spasms ceased in 2 of 5 patients treated with VGB and in 11 of 12 patients treated with ACTH. After 3 months, relapses of spasms were observed in 6 patients treated with ACTH and in 1 treated with VGB. VGB produced a therapeutic response in nearly half the patients receiving this drug.

CONCLUSIONS

Our data lend further support to the view that VGB may be considered a first-choice drug in the treatment of IS.

Homozygosity mapping of Hallervorden-Spatz syndrome to chromosome 20p12.3-p13

Hallervorden-Spatz syndrome (HSS) (OMIM #234200) is a rare, autosomal recessive neurode-generative disorder with brain iron accumulation as a prominent finding. Clinical features include extrapyramidal dysfunction, onset in childhood, and a relentlessly progressive course. Histologic study reveals massive iron deposits in the basal ganglia. Systemic and cerebrospinal fluid iron levels are normal, as are plasma levels of ferritin, transferrin and ceruloplasmin. Conversely, in disorders of systemic iron overload, such as haemochromatosis, brain iron is not increased, which suggests that fundamental differences exist between brain and systemic iron metabolism and transport. In normal brain, non-haem iron accumulates regionally and is highest in basal ganglia. Pathologic brain iron accumulation is seen in common disorders, including Parkinson's disease, Alzheimer's disease and Huntington disease. In order to gain insight into normal and abnormal brain iron transport, metabolism and function, our approach was to map the gene for HSS. A primary genome scan was performed using samples from a large, consanguineous family (HS1) (see Fig. 1). While this family was immensely powerful for mapping, the region demonstrating homozygosity in all affected members spans only 4 cM, requiring very close markers in order to detect linkage. The HSS gene maps to an interval flanked by D20S906 and D20S116 on chromosome 20p12.3-p13. Linkage was confirmed in nine additional families of diverse ethnic backgrounds.

Familial white matter hypoplasia, agenesis of the corpus callosum, mental retardation and growth deficiency: a new distinctive syndrome

We have observed in two different families two pairs of male siblings born from normal, non-consanguineous parents having the same syndrome, characterized by severe cerebral white matter hypoplasia, agenesis or extreme hypoplasia of the corpus callosum, mental retardation, failure to thrive and minor midline facial abnormalities. This seems to be a previously unreported genetic syndrome.

Unusual cyclosporin related neurological complications in recipients of liver transplants

In a series of 256 recipients of paediatric liver transplants, from 1984 to 1990, four patients presented with sudden onset seizures not explained by conventional work-up. None had a family or personal history of seizures. Infectious causes were excluded. There were no glucose or electrolyte disturbances. Seizures were not induced by systemic or intracranial hypertension. One child out of four had transient white matter and cortex focal lesions on computed tomography of the brain. One to 10 days before seizures all four children presented with supratherapeutic concentrations of serum cyclosporin that were determined by a non-specific method that measured the parent compound plus its metabolites. The supratherapeutic concentrations were not found with the specific method measuring cyclosporin alone. It is concluded that these seizures may correspond to a toxic effect of cyclosporin, probably due to one or several metabolites, as suggested by the discrepancy between specific and non-specific methods of determination.