Dandy-Walker Phenotype with Brainstem Involvement: 2 Distinct Subgroups with Different Prognosis

BACKGROUND AND PURPOSE

Although cardinal imaging features for the diagnostic criteria of the Dandy-Walker phenotype have been recently defined, there is a large range of unreported malformations among these patients. The brainstem, in particular, deserves careful attention because malformations in this region have potentially important implications for clinical outcomes. In this article, we offer detailed information on the association of brainstem dysgenesis in a large, multicentric cohort of patients with the Dandy-Walker phenotype, defining different subtypes of involvement and their potential clinical impact.

MATERIALS AND METHODS

In this established multicenter cohort of 329 patients with the Dandy-Walker phenotype, we include and retrospectively review the MR imaging studies and clinical records of 73 subjects with additional brainstem malformations. Detailed evaluation of the different patterns of brainstem involvement and their potential clinical implications, along with comparisons between posterior fossa measurements for the diagnosis of the Dandy-Walker phenotype, was performed among the different subgroups of patients with brainstem involvement.

RESULTS

There were 2 major forms of brainstem involvement in patients with Dandy-Walker phenotype including the following: 1) the mild form with anteroposterior disproportions of the brainstem structures "only" (57/73; 78%), most frequently with pontine hypoplasia (44/57; 77%), and 2) the severe form with patients with tegmental dysplasia with folding, bumps, and/or clefts (16/73; 22%). Patients with severe forms of brainstem malformation had significantly increased rates of massive ventriculomegaly, additional malformations involving the corpus callosum and gray matter, and interhemispheric cysts. Clinically, patients with the severe form had significantly increased rates of bulbar dysfunction, seizures, and mortality.

CONCLUSIONS

Additional brainstem malformations in patients with the Dandy-Walker phenotype can be divided into 2 major subgroups: mild and severe. The severe form, though less prevalent, has characteristic imaging features, including tegmental folding, bumps, and clefts, and is directly associated with a more severe clinical presentation and increased mortality.

Medullary Tegmental Cap Dysplasia: Fetal and Postnatal Presentations of a Unique Brainstem Malformation

BACKGROUND AND PURPOSE

Medullary tegmental cap dysplasia is a rare brainstem malformation, first described and defined by James Barkovich in his book Pediatric Neuroimaging from 2005 as an anomalous mass protruding from the posterior medullary surface. We describe the neuroimaging, clinical, postmortem, and genetic findings defining this unique malformation.

MATERIALS AND METHODS

This is a multicenter, international, retrospective study. We assessed the patients' medical records, prenatal ultrasounds, MR images, genetic findings, and postmortem results. We reviewed the medical literature for all studies depicting medullary malformations and evaluated cases in which a dorsal medullary protuberance was described.

RESULTS

We collected 13 patients: 3 fetuses and 10 children. The medullary caps had multiple characteristics. Associated brain findings were a rotated position of the medulla, a small and flat pons, cerebellar anomalies, a molar tooth sign, and agenesis of the corpus callosum. Systemic findings included the following: polydactyly, hallux valgus, large ears, and coarse facies. Postmortem analysis in 3 patients revealed that the cap contained either neurons or white matter tracts. We found 8 publications describing a dorsal medullary protuberance in 27 patients. The syndromic diagnosis was Joubert-Boltshauser syndrome in 11 and fibrodysplasia ossificans progressiva in 14 patients.

CONCLUSIONS

This is the first study to describe a series of 13 patients with medullary tegmental cap dysplasia. The cap has different shapes: distinct in Joubert-Boltshauser syndrome and fibrodysplasia ossificans progressive. Due to the variations in the clinical, imaging, and postmortem findings, we conclude that there are multiple etiologies and pathophysiology. We suggest that in some patients, the pathophysiology might be abnormal axonal guidance.

Refining the Neuroimaging Definition of the Dandy-Walker Phenotype

BACKGROUND AND PURPOSE

The traditionally described Dandy-Walker malformation comprises a range of cerebellar and posterior fossa abnormalities with variable clinical severity. We aimed to establish updated imaging criteria for Dandy-Walker malformation on the basis of cerebellar development.

MATERIALS AND METHODS

In this multicenter study, retrospective MR imaging examinations from fetuses and children previously diagnosed with Dandy-Walker malformation or vermian hypoplasia were re-evaluated, using the choroid plexus/tela choroidea location and the fastigial recess shape to differentiate Dandy-Walker malformation from vermian hypoplasia. Multiple additional measures of the posterior fossa and cerebellum were also obtained and compared between Dandy-Walker malformation and other diagnoses.

RESULTS

Four hundred forty-six examinations were analyzed (174 fetal and 272 postnatal). The most common diagnoses were Dandy-Walker malformation (78%), vermian hypoplasia (14%), vermian hypoplasia with Blake pouch cyst (9%), and Blake pouch cyst (4%). Most measures were significant differentiators of Dandy-Walker malformation from non-Dandy-Walker malformation both pre- and postnatally (P < .01); the tegmentovermian and fastigial recess angles were the most significant quantitative measures. Posterior fossa perimeter and vascular injury evidence were not significant differentiators pre- or postnatally (P > .3). The superior posterior fossa angle, torcular location, and vermian height differentiated groups postnatally (P < .01), but not prenatally (P > .07).

CONCLUSIONS

As confirmed by objective measures, the modern Dandy-Walker malformation phenotype is best defined by inferior predominant vermian hypoplasia, an enlarged tegmentovermian angle, inferolateral displacement of the tela choroidea/choroid plexus, an obtuse fastigial recess, and an unpaired caudal lobule. Posterior fossa size and torcular location should be eliminated from the diagnostic criteria. This refined phenotype may help guide future study of the numerous etiologies and varied clinical outcomes.

Can MRI Differentiate between Infectious and Immune-Related Acute Cerebellitis? A Retrospective Imaging Study

BACKGROUND AND PURPOSE

Acute cerebellitis is an acute neurologic condition attributable to a recent or concurrent infection or a recent vaccination or ingestion of medication, with MR imaging evidence of cerebellar edema. MR imaging can confirm an anatomic abnormality and may allow the radiologist to establish a differential diagnosis. The purpose of this research was to evaluate the MR imaging findings in children with acute cerebellitis due to infectious versus immune-related conditions, in particular whether MR imaging findings allow differentiation.

MATERIALS AND METHODS

Electronic medical records were reviewed between 2003 and 2020 in our quaternary children's hospital. Data included demographics and clinical records: presentation/symptoms, final diagnosis including acute cerebellitis and immune-related acute cerebellitis, length of stay, treatment, condition at discharge, and laboratory findings. Retrospective independent review of all brain MR imaging studies was performed.

RESULTS

Forty-three patients (male/female ratio, 28:15) were included in this study. Average age at presentation was 7.08 years (range, 0.05-17.52 years). Thirty-five children had infectious and 8 children had immune-related acute cerebellitis. Significant differences in neuroimaging were the following: 1) T2-FLAIR hyperintense signal in the brainstem (37.50% versus 2.85%, P = .016); 2) T2-FLAIR hyperintense signal in the supratentorial brain higher in the immune-related group (37.50% versus 0.00%, P = .004); and 3) downward herniation, higher in the infectious acute cerebellitis group (42.85% versus 0.00%, P = .03).

CONCLUSIONS

Acute cerebellitis is a rare condition, and MR imaging is helpful in the differential diagnosis. T2-FLAIR hyperintense signal in the brainstem and supratentorial brain may be indicative of immune-related acute cerebellitis, and downward herniation may be indicative of infectious acute cerebellitis.

Neuroimaging Features of Ectopic Cerebellar Tissue: A Case Series Study of a Rare Entity

Ectopic cerebellar tissue is a rare entity likely secondary to multiple, interacting, developmental errors during embryogenesis. Multiple sites of ectopic cerebellar tissue have been reported, including extracranial locations; however, an intracranial location is most common. We report on the MR imaging findings of a multi-institutional series of 7 ectopic cerebellar tissue cases (2 males, 4 females, 1 fetal) ranging from 22 weeks 5 days' gestational age to 18 years of age. All cases of ectopic cerebellar tissue were diagnosed incidentally, while imaging was performed for other causes. Ectopic cerebellar tissue was infratentorial in 6/7 patients and supratentorial in 1/7 patients. All infratentorial ectopic cerebellar tissue was connected with the brain stem or cerebellum. MR imaging signal intensity was identical to the cerebellar gray and white matter signal intensity on all MR imaging sequences in all cases. Ectopic cerebellar tissue should be considered in the differential diagnoses of extra-axial masses with signal characteristics similar to those of the cerebellum. Surgical biopsy or resection is rarely necessary, and in most cases, MR imaging is diagnostic.

A clinical diagnostic algorithm for early onset cerebellar ataxia

Early onset cerebellar Ataxia (EOAc) comprises a large group of rare heterogeneous disorders. Determination of the underlying etiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This may change the diagnostic work-up into a time-consuming, costly and not always rewarding task. In this overview, the Childhood Ataxia and Cerebellar Group of the European Pediatric Neurology Society (CACG-EPNS) presents a diagnostic algorithm for EOAc patients. In seven consecutive steps, the algorithm leads the clinician through the diagnostic process, including EOA identification, application of the Inventory of Non-Ataxic Signs (INAS), consideration of the family history, neuro-imaging, laboratory investigations, genetic testing by array CGH and Next Generation Sequencing (NGS). In children with EOAc, this algorithm is intended to contribute to the diagnostic process and to allow uniform data entry in EOAc databases.

MKS1 mutations cause Joubert syndrome with agenesis of the corpus callosum

Joubert syndrome (JS) is a clinically and genetically heterogeneous ciliopathy characterized by episodic hyperpnea and apnea, hypotonia, ataxia, cognitive impairment and ocular motor apraxia. The "molar tooth sign" is pathognomonic of this condition. Mutations in the MKS1 gene are a major cause of Meckel-Gruber syndrome (MKS), the most common form of syndromic neural tube defects, frequently resulting in perinatal lethality. We present the phenotype and genotype of a child with severe JS and agenesis of the corpus callosum (ACC). In our patient, a next generation sequencing (NGS) approach revealed the following two variants of the MKS1 gene: first, a novel missense variant [ c.240G > T (p.Trp80Cys)], which affects a residue that is evolutionarily highly conserved in mammals and ciliates; second, a 29 bp deletion in intron 15 [c.1408-35_1408-7del29], a founder mutation, which in a homozygous state constitutes the major cause of MKS in Finland. We review the MKS1-variants in all of the eleven JS patients reported to date and compare these patients to our case. To our knowledge, this is the first patient with Joubert syndrome and agenesis of the corpus callosum where a potentially causal genotype is provided.

Phacomatosis pigmentovascularis and extensive venous malformation of brain vessels: an unknown association or a new vascular neurocutaneous syndrome?

We report on a 16-year-old intelligent and sportive boy with the cutaneous findings of phacomatosis pigmentovascularis unclassifiable type.The skin anomaly was lateralised to his left body side since birth, fading over the years. Because of headache and dizziness, brain magnetic resonance imaging was performed, which revealed an impressive enlargement of subependymal, deep and superficial medullary veins on the right side combined with a mild atrophy of the ipsilateral parietal region. We propose to investigate patients with phacomatosis pigmentovascularis for associated venous brain malformations with adequate imaging techniques.

Tecto-cerebellar dysraphism with occipital encephalocele: not a distinct disorder, but part of the Joubert syndrome spectrum?

Magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) findings in a 4-year-old child with occipital encephalocele, cerebellar vermis hypogenesis, and tectal malformation are presented. The neuroimaging findings are reminiscent of tectocerebellar dysraphism with an occipital encephalocele (TCD-OE). Additionally, elongated, thickened, and horizontally orientated superior cerebellar peduncles, an abnormally deepened interpeduncular fossa, subependymal heterotopia, and focal cortical dysplasia were noted. Color-coded fractional anisotropy (FA) maps revealed an absence of the decussation of the superior cerebellar peduncles. These findings are highly suggestive of Joubert syndrome and related disorders (JSRD). Our report and the review of the published cases suggest that TCD-OE is not a nosological entity, but may represent the structural manifestation of heterogeneous disorders such as the JSRD spectrum. DTI may be very helpful to differentiate between similar midbrain-hindbrain malformations.

Joubert syndrome and related disorders: spectrum of neuroimaging findings in 75 patients

VH and MTS are the neuroimaging hallmarks of JSRD. We aimed to look at the full spectrum of neuroimaging findings in JSRD and reviewed the MR imaging of 75 patients with JSRD, including 13 siblings and 4 patients with OFD VI. All patients had VH and enlargement of the fourth ventricle. The degree of VH and the form of the MTS were variable. In most patients, the cerebellar hemispheres were normal and the PF was enlarged. Brain stem morphology was abnormal in 30% of the patients. Supratentorial findings included hippocampal malrotation, callosal dysgenesis, migration disorders, cephaloceles, and ventriculomegaly. All patients with OFD VI had a similar pattern, including HH in 2 patients. No neuroimaging-genotype correlation could be found. The wide neuroimaging spectrum in our patients supports the heterogeneity of JSRD. Neuroimaging differences in siblings represent intrafamilial heterogeneity. Due to the absence of a correlation with genotype, neuroimaging findings are of limited value in classifying patients with JSRD.

Interpeduncular heterotopia in Joubert syndrome: a previously undescribed MR finding

The so-called molar tooth sign is the radiologic hallmark of JSRD. Joubert syndrome is a rare, most often autosomal-recessive disorder with a characteristic malformation of the midhindbrain. We describe 3 patients with JSRD and the additional MR finding of tissue resembling heterotopia in the interpeduncular fossa, which in one patient was combined with a more extensive intramesencephalic heterotopia. Interpeduncular heterotopia has not been reported previously, either in the context of JSRD or as a separate entity. This new imaging feature enlarges the spectrum of brain stem abnormalities in JSRD. In view of the underlying ciliopathy, it seems likely that the interpeduncular heterotopia results from misdirected migration.

Cavernous malformations of the central nervous system in children: presentation, treatment and outcome of 20 cases

BACKGROUND

Cavernous malformations (CM) of the central nervous system are vascular malformations responsible for symptoms such as seizures, headache, and neurological deficits: 25% of cases already present in childhood.

MATERIAL AND METHODS

Retrospective study including all CMs of the central nervous system in childhood diagnosed in the period 1993-2008 in 3 paediatric hospitals in Switzerland, focusing on clinical manifestations, neuroimaging findings, treatment, and outcome.

RESULTS

20 children (13 females) were diagnosed with CM, with an average age at presentation of 8.5 years (range 7 months-16 years). 17/20 presented with acute haemorrhage, 9/17 with seizures, 5/17 with focal neurological symptoms, and 3/17 with severe headache only. Localisation was supratentorial in 15/20, infratentorial in 2/20, supra- and infratentorial in 2/20, and spinal in 1 child. Five children had multiple CMs. Treatment was conservative in 10 cases and surgery was indicated in 10: for acute haemorrhage in 5; recurrent bleeding in 3; and epilepsy in 2. Follow-up after diagnosis was 0.5 years-10 years (mean 4 years), revealing neurological sequelae in 6 patients. The CM increased in size in 2 cases with an increase in number also in 1 of these.

CONCLUSIONS

We confirm that CMs in childhood mainly present with seizures, severe headache, or focal symptoms due to acute haemorrhage. During infancy they may appear as dynamic lesions increasing in size and/or number. The regular application of newer neuroimaging techniques such as susceptibility weighted imaging will detect more lesions but not necessarily resolve problems concerning optimum treatment.

Postnatal in-vivo MRI findings in anencephaly

We report on the MRI findings of an anencephalic infant who survived 10 weeks postnatally. MRI showed absence of the cranial vault, all supratentorial structures, and the cerebellum. A brainstem primordium without pontine prominence was present. The brainstem was surrounded by the area cerebrovasculosa. The absence of a pontine prominence in an anencephalic infant without cerebellar tissue supports the hypothesis that absent pontine prominence is found in children with a prenatal loss of cerebellar tissue.

Disturbed Wnt Signalling due to a Mutation in CCDC88C Causes an Autosomal Recessive Non-Syndromic Hydrocephalus with Medial Diverticulum

The etiology of non-syndromic hydrocephalus is poorly understood. Via positional cloning in a consanguineous family with autosomal recessive hydrocephalus we have now identified a homozygous splice site mutation in the CCDC88C gene as a novel cause of a complex hydrocephalic brain malformation. The only living patient showed normal psychomotor development at the age of 3 years and 3 months and her deceased aunt, who was assumed to suffer from the same condition, had mild mental retardation. The mutation in the affected patients, a homozygous substitution in the donor splice site of intron 29, resulted in a shorter transcript due to exclusion of exon 29 and loss of functional protein, as shown by Western blotting (p.S1591HfsX7). In normal human tissue panels, we found CCDC88C ubiquitously expressed, but most prominently in the fetal brain, especially in pons and cerebellum, while expression in the adult brain appeared to be restricted to cortex and medulla oblongata. CCDC88C encodes DAPLE (HkRP2), a Hook-related protein with a binding domain for the central Wnt signalling pathway protein Dishevelled. Targeted quantitative RT-PCR and expression profiling of 84 genes from the Wnt signalling pathway in peripheral blood from the index patient and her healthy mother revealed increased mRNA levels of CCDC88C indicating transcriptional upregulation. Due to loss of CCDC88C function β-catenin (CTNNB1) and the downstream target LEF1 showed increased mRNA levels in the patient, but many genes from the Wnt pathway and transcriptional target genes showed reduced expression, which might be explained by a complex negative feedback loop. We have thus identified a further essential component of the Wnt signalling pathway in human brain development.

Normal cognitive functions in joubert syndrome

Developmental delay and subsequent impaired cognitive functions are present in almost all patients with Joubert syndrome (JS). We report on a 20-year-old woman with mild clinical signs of JS (minimal truncal ataxia and oculomotor apraxia) but typical molar tooth sign on neuroimaging, normal full scale (IQ=93), verbal (IQ=93), and performance intelligence quotient (IQ=94). Only minor difficulties in visual-spatial organization and in some executive functions could be detected. This pattern of deficits is partly reminiscent of the cerebellar cognitive affective syndrome. Her diagnosis was only reached following the diagnosis of JS in two brothers with severe cognitive impairment. Molecular investigations demonstrated a homozygous mutation in the INPP5E gene. This exceptional observation confirms that normal cognitive functions are possible in JS and corroborates the well known intrafamilial variability.

Cerebellar cleft: confirmation of the neuroimaging pattern

We recently described the neuroimaging and clinical findings in 6 children with cerebellar clefts and proposed that they result from disruptive changes following prenatal cerebellar hemorrhage. We now report an additional series of 9 patients analyzing the clinical and neuroimaging findings. The clefts were located in the left cerebellar hemisphere in 5 cases, in the right in 3, and bilaterally in one child who had bilateral cerebellar hemorrhages as a preterm infant at 30 weeks gestation. In one patient born at 24 weeks of gestation a unilateral cerebellar hemorrhage has been found at the age of 4 months. Other findings included disordered alignment of the folia and fissures, an irregular gray/white matter junction, and abnormal arborization of the white matter in all cases. Supratentorial abnormalities were found in 4 cases. All but 2 patients were born at term. We confirm the distinct neuroimaging pattern of cerebellar clefts. Considering the documented fetal cerebellar hemorrhage in our first series, we postulate that cerebellar clefts usually represent residual disruptive changes after a prenatal cerebellar hemorrhage. Exceptionally, as now documented in 2 patients, cerebellar clefts can be found after neonatal cerebellar hemorrhages in preterm infants. The short-term outcome in these children was variable.

Pontine tegmental cap dysplasia: the severe end of the clinical spectrum

Pontine tegmental cap dysplasia (PTCD) is a newly described hindbrain malformation with distinct neuroradiological findings. Only 12 cases of PTCD have been described so far, all sporadic. We report 2 further patients. Both children presented after birth with significant feeding problems due to impaired mouth opening (previously not reported) and sucking difficulties. Facial, cochlear, and glossopharyngeal nerves were involved resulting in bilateral sensory deafness and a significant swallowing disorder requiring a gastrostomy. In one patient the trigeminal sensory nerve was also involved causing severe bilateral corneal clouding with impaired vision. Both patients showed only minimal developmental progress since birth and had no speech production. Furthermore, they had vertebral and rib anomalies. The patients died at the age of 15 and 32 months, respectively, due to intercurrent infections. The majority of patients reported previously were affected less severely. The presented patients may represent the severe end of the spectrum.

Outcome in children with brain tumours diagnosed in the first year of life: long-term complications and quality of life

OBJECTIVE

To study the outcome in children with brain tumours diagnosed in the first year of life, we followed up 27 consecutive children who were diagnosed between 1980 and 2005 in a single institution.

METHODS

Tumour control and neurological, endocrine and cognitive complications and their impact on behavioural and emotional adjustment and health-related quality of life (HRQoL) were comprehensively assessed in 11 survivors (mean follow-up time 12.3 years).

RESULTS

Persistent neurological complications occurred in 9/11 patients, endocrine and growth complications in 4/11, and cognitive deficits leading to school problems/impaired choice of occupation in 8/10. Behavioural and psychological adjustment problems were reported by 4/6 patients and 7/10 parents. HRQoL as rated by patients and their parents was considerably lower than that of healthy controls. In comparison with healthy controls, social functioning was rated by the patients and the parents as the QoL dimension most affected. HRQoL was lowest for patients with high-grade tumour histology and more intense therapy.

CONCLUSION

Long-term survivors of brain tumours diagnosed in the first year of life are not only at great risk of neurological and cognitive complications, but also of social isolation thereby substantially decreasing self-rated HRQoL.

RPGRIP1L mutations are mainly associated with the cerebello-renal phenotype of Joubert syndrome-related disorders

Joubert syndrome-related disorders (JSRDs) are autosomal recessive pleiotropic conditions sharing a peculiar cerebellar and brainstem malformation known as the 'molar tooth sign' (MTS). Recently, mutations in a novel ciliary gene, RPGRIP1L, have been shown to cause both JSRDs and Meckel-Gruber syndrome. We searched for RPGRIP1L mutations in 120 patients with proven MTS and phenotypes representative of all JSRD clinical subgroups. Two homozygous mutations, the previously reported p.T615P in exon 15 and the novel c.2268_2269delA in exon 16, were detected in 2 of 16 families with cerebello-renal presentation ( approximately 12%). Conversely, no pathogenic changes were found in patients with other JSRD phenotypes, suggesting that RPGRIP1L mutations are largely confined to the cerebello-renal subgroup, while they overall represent a rare cause of JSRD (<2%).

Cerebellar cleft: a form of prenatal cerebellar disruption

In contrast to malformations, cerebellar disruptions have attracted little interest in the literature. We draw attention for the first time to the hypothesis that cerebellar clefts are residual changes following a prenatal cerebellar insult, and represent disruptions. We reviewed the clinical records and MR findings of six patients with a cerebellar cleft, two of whom also had prenatal MRI at 24 weeks of gestation. The clefts were located in the left cerebellar hemisphere in five cases, in the right in one patient. Other typical findings included disorderly alignment of the cerebellar folia and fissures, irregular gray/white matter junction, and abnormal arborization of the white matter in all patients. The cerebellar cleft extended into the fourth ventricle in three cases, and in two children cystic cortical lesions were seen. Supratentorial schizencephaly was found in two patients. In two patients there was a documented fetal cerebellar hemorrhage at 24 weeks of gestation. We conclude that cerebellar clefts are residual changes resulting from a prenatal cerebellar insult and consequently represent disruptions rather than primary malformations. The supratentorial findings are also in agreement with an acquired lesion. The outcome in these children was variable, mainly depending of the presence of supratentorial lesions.

Prenatal and neonatal MR imaging findings in oral-facial-digital syndrome type VI

We report prenatal and neonatal neuroimaging findings in a case of oral-facial-digital syndrome type VI (OFDS VI). Prenatal MR imaging at 29 weeks' gestation showed hypoplastic cerebellar vermis and hemispheres, the molar tooth sign, and a hypothalamic hamartoma. Neonatal MR imaging confirmed these findings. The neonate developed breathing abnormalities and exhibited frontal bossing, multiple bucco-alveolar frenula, and postaxial hexadactyly of both hands. If the molar tooth sign and a hypothalamic hamartoma are present, prenatal diagnosis of OFDS VI is possible.

Diffusion tensor imaging in Joubert syndrome

BACKGROUND AND PURPOSE

Neuropathologic findings and preliminary imaging studies demonstrated the absence of pyramidal tract and superior cerebellar peduncular decussation in individual patients with Joubert syndrome (JS). We hypothesized that functional-structural neuroimaging findings do not differ between the genetic forms of JS.

MATERIALS AND METHODS

MR imaging was performed with a 3T MR imaging-unit. Multiplanar T2- and T1-weighted imaging was followed by diffusion tensor imaging (DTI). Isotropic diffusion-weighted images, apparent diffusion coefficient maps, and color-coded fractional anisotropy maps, including tractography, were subsequently calculated.

RESULTS

In all 6 patients studied, DTI showed that the fibers of the superior cerebellar peduncles did not decussate in the mesencephalon and the corticospinal tract failed to cross in the caudal medulla. The patients represented various genetic forms of JS.

CONCLUSION

In JS, the fibers of the pyramidal tract and the superior cerebellar peduncles do not cross, irrespective of the underlying mutation.

Brainstem disconnection: case report and review of the literature

We report a neonate with brainstem disconnection. Only five similar cases have previously been described, the longest survival was 7 weeks. The newborn exhibited muscular hypertonia, absent suction, insufficient breathing, and seizures. Magnetic resonance imaging showed a disconnection between the upper pons and the medulla oblongata and cerebellar hypoplasia. The basilar artery was not visible. These neuroimaging findings are clearly different from other midbrain or hindbrain malformations with cerebellar hypoplasia. This pattern and a previously reported autopsy point to a malformation, not a disruption.

Prolonged hemiplegic episodes in children due to mutations in ATP1A2

BACKGROUND

Familial hemiplegic migraine (FHM) is an unusual migraine syndrome characterised by recurrent transient attacks of unilateral weakness or paralysis as part of the migraine aura. Genetically and clinically heterogeneous, FHM1 is caused by mutations in CACNA1A and FHM2 by mutations in ATP1A2.

AIM

Three children with prolonged hemiplegia were tested for mutations in CACNA1A or ATP1A2.

METHODS

Mutations in CACNA1A and ATP1A2 were screened for by denaturing high performance liquid chromatography and confirmed by sequencing. Expression studies were performed to characterise the functional consequences of these mutations.

RESULTS

No mutation was found in the FHM1 gene while three mutations were identified in the FHM2 gene. All three mutations were missense: two were novel and one was de novo; none was found in controls. Functional studies in HeLa cells showed complete loss of mutant pump function without interfering with the wild-type pump, consistent with haploinsufficiency.

CONCLUSION

We identified novel disease causing mutations in the FHM2 gene. Genetic screening for FHM should be considered in a child with prolonged hemiplegia even if there is no prior history or family history of migraine or hemiplegic episodes.

Ataxia, delayed dentition and hypomyelination: a novel leukoencephalopathy

We present four children, three of them boys, affected with an identical clinical pattern consisting of early-onset ataxia, delayed dentition, hypomyelination and cerebellar atrophy. Dental radiographs showed variable absence of succedaneous teeth. Proton MR spectroscopy in one child showed elevated white matter myo-inositol. As the clinical and radiological picture in these patients is identical to that of four cases described earlier, we suggest that this disorder with ataxia, delayed dentition and hypomyelination (ADDH) represents a new entity. With the characteristic tooth abnormalities it should be straightforward to identify new patients in order to facilitate the search for the underlying genetic defect.

Contribution of diffusion tensor MR imaging in detecting cerebral microstructural changes in adults with neurofibromatosis type 1

BACKGROUND AND PURPOSE

After an early progression of signal intensity changes in T2-weighted MR images, also known as "neurofibromatosis bright objects," in patients with neurofibromatosis type 1 (NF-1), there is a tendency toward regression or even disappearance in early adulthood. The purpose of this study was to investigate whether adult patients with NF-1 exhibit generalized microstructural alterations even in normal-appearing brain regions.

MATERIALS AND METHODS

Conventional and diffusion tensor MR imaging of the brain was obtained in 10 adult patients with NF-1 and 10 age-matched healthy volunteers. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in brain stem, basal ganglia, thalamus, corpus callosum, and frontal and parietooccipital white matter regions.

RESULTS

Significantly increased ADC and decreased FA values were found in all regions of interest and in all patients with NF-1, irrespective of their scholastic achievement and subsequent professional performance, compared with control subjects (P < .001). There were no significant correlations with the age (P > .1) or with the lateralization between brain hemispheres (P > .05).

CONCLUSION

Diffusion tensor imaging reveals globally elevated FA and decreased ADC values in the mature brains of patients with NF-1, which is most likely a consequence of diffuse and basic alterations in cerebral microstructure that result from the underlying gene mutation.

Loss-of-function mutations in the Nav1.7 gene underlie congenital indifference to pain in multiple human populations

Congenital indifference to pain (CIP) is a rare condition in which patients have severely impaired pain perception, but are otherwise essentially normal. We identified and collected DNA from individuals from nine families of seven different nationalities in which the affected individuals meet the diagnostic criteria for CIP. Using homozygosity mapping and haplotype sharing methods, we narrowed the CIP locus to chromosome 2q24-q31, a region known to contain a cluster of voltage-gated sodium channel genes. From these prioritized candidate sodium channels, we identified 10 mutations in the SCN9A gene encoding the sodium channel protein Nav1.7. The mutations completely co-segregated with the disease phenotype, and nine of these SCN9A mutations resulted in truncation and loss-of-function of the Nav1.7 channel. These genetic data further support the evidence that Nav1.7 plays an essential role in mediating pain in humans, and that SCN9A mutations identified in multiple different populations underlie CIP.

Serial MR imaging, diffusion tensor imaging, and MR spectroscopic findings in a child with progressive encephalopathy, edema, hypsarrhythmia, and optic atrophy (PEHO) syndrome

PEHO syndrome is a rare symptom complex of severe progressive encephalopathy, edema, hypsarrhythmia, and optic atrophy. Disease onset is in early infancy. The current case report presents and discusses serial conventional MR imaging findings and serial functional studies including diffusion tensor imaging and quantitative MR spectroscopy findings in a 6-year-old child with PEHO.

Spontaneous pregnancy outcome after prenatal diagnosis of anencephaly

Parents are usually told that many anencephalic offspring die in utero or soon after delivery, and many obstetricians offer elective termination of the pregnancy. Following the personal experience of the first author, a personal website was created with the intention of providing information and exchanging views with other parents confronted with a prenatal diagnosis of anencephaly. Data were collected from 211 pregnancies where the parents opted not to terminate pregnancy. These data revealed that polyhydramnios was a feature in 56 (26%) pregnancies, death in utero in 15 (7%) pregnancies, 72 (34%) babies were born prematurely (<37 weeks of gestation), 113 (53%) at term and 21 (10%) after 42 weeks. Stillbirth, presumably resulting from intrapartum death, occurred in 43 (20%) deliveries. One hundred and fifty-three (72%) of anencephalic offspring were liveborn, of those, 103 (67%) died within 24 hours but 6/211 survived 6 or more days (maximum 28 days). Continuation of pregnancy after a diagnosis of anencephaly is medically safe and should be considered as an option.

Clinical profiles of four patients with Rett syndrome carrying a novel exon 1 mutation or genomic rearrangement in the MECP2 gene

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked MECP2 gene encoding methyl CpG binding protein 2 (MeCP2). Recently, a new isoform of MeCP2 including exon 1 was identified. This new isoform is more abundantly expressed in brain than the isoform including exons 2-4. Very little is known about the phenotypes associated with mutations in exon 1 of MECP2 since only a limited number of RTT patients carrying such mutations have been identified so far. In this study, we screened a cohort of 20 girls with RTT for exon 1 mutations by sequencing and multiplex ligation-dependent probe amplification (MLPA). We identified one girl with a novel exon 1 mutation (c.30delCinsGA) by sequencing and three with genomic rearrangements by MLPA. Comparison of the phenotypes showed that the girls carrying a mutation or rearrangement encompassing exon 1 were more severely affected than the girls with rearrangements not affecting exon 1.

Acute flaccid paralysis as initial symptom in 4 patients with novel E1alpha mutations of the pyruvate dehydrogenase complex

We report on 4 boys from 3 families presenting initially in infancy with an acute onset of flaccid tetraparesis and areflexia, resembling Guillain-Barré syndrome (GBS). However, the cerebrospinal fluid (CSF) protein was normal, while serum and CSF lactate were elevated. All patients had recurrent similar episodes, usually associated with infections. Brain MRI showed T (2) hyperintensities in the basal ganglia in two boys, in one of them at the first clinical presentation; the other one had a normal brain MRI during the first episode. A third boy had a normal MRI twice but an increased lactate peak in the basal ganglia in (1)H-MR spectroscopy. Motor nerve conduction velocities (NCV) were normal in all patients. Biochemical analyses of muscle tissue, performed in two patients, revealed a deficiency of the pyruvate dehydrogenase (PDH). Molecular genetic analysis of the X-chromosomal E1alpha subunit of PDH showed three new mutations in phylogenetically conserved areas of the protein: Glu358Lys in patient 1; Arg88Lys in patient 2 and 3 (brothers); and Leu216Ser in patient 4. In conclusion, children with "atypical GBS" should be evaluated for a mitochondrial disorder, including pyruvate dehydrogenase deficiency, even after a first episode.

Conservative management of significant epidural haematomas in children

OBJECTIVE

A significant epidural haematoma (EDH) is generally treated by craniotomy and evacuation. This is a report of conservative management following an EDH on computerized tomography (CT) in a paediatric population. The authors examined whether conservative treatment of radiologically significant EDH is a successful and safe therapeutic option.

METHODS

Retrospective data were collected from charts of patients with conservatively treated EDH in the Department of Surgery of the University Children's Hospital Zurich between September 1993 and January 2004. Included were patients without focal neurological deficits, with a Glasgow Coma Scale (GCS) of 15 and an initial CT demonstrating an EDH with a minimal thickness of 1 cm. Mild clinical symptoms of raised intracranial pressure such as headache, nausea or vomiting were treated symptomatically. Follow-up included a standardized interview, a neuropaediatric examination and CT.

RESULTS

Thirteen children with EDH had successful conservative management. Only one 12-year-old female patient with a delayed diagnosed frontal EDH required surgical intervention 24 h after admission and 5 days after the accident. Clinical follow-up showed patients without neurological deficits, a Glasgow Outcome Scale of 5 and no post-traumatic sequelae over an average of 4 4/12 years (range 4 months to 10 4/12 years). Follow-up CT showed complete resolution of the EDH within 2 to 3 months.

CONCLUSIONS

Our results demonstrate that significant EDH can be treated non-operatively in neurologically normal children. We recommend that such treatment be performed in specialised paediatric centres under adequate neurological observation since prompt emergency operation in case of neurological deterioration should be provided.

Neuropsychological problems after paediatric stroke: two year follow-up of Swiss children

AIM

The aim of this study was to obtain information about neurological and cognitive outcome for a population-based group of children after paediatric ischaemic stroke.

METHODS

Data from the Swiss neuropaediatric stroke registry (SNPSR), from 1.1.2000 to 1.7.2002, including children (AIS 1) and neonates (AIS 2). At 18-24 months after a stroke, a follow-up examination was performed including a history, neurological and neuropsychological assessment.

RESULTS

33/48 children (22 AIS 1, 11 AIS 2) participated in the study. Neurological outcome was good in 16/33. After childhood stroke mean IQ levels were normal (94), but 6 children had IQ < 85 (50-82) and neuropsychological problems were present in 75%. Performance IQ (93) was reduced compared to verbal IQ (101, p = 0.121) due to problems in the domain of processing speed (89.5); auditory short-term memory was especially affected. Effects on school career were common. Outcome was worse in children after right-sided infarction. Children suffering from stroke in mid-childhood had the best prognosis. There was no clear relationship between outcome and localisation of the lesion. After neonatal stroke 7/11 children showed normal development and epilepsy indicated a worse prognosis in the remaining 4.

CONCLUSION

After paediatric stroke neuropsychological problems are present in about 75% of children. Younger age at stroke as well as an emergence of epilepsy were predictors for worse prognosis.

Outcome of medulloblastoma in children: long-term complications and quality of life

To study the outcomes in long-term survivors of paediatric medulloblastoma (MB), we followed 51 consecutive children who were treated between 1980 and 2000 in a single institution. In 18 of 26 survivors (mean follow-up time 12.2 years), tumour control, neurological, endocrine, and neurocognitive complications and their impact on behavioural and psychological adjustment, and health-related quality of life (QoL) were comprehensively assessed using qualitative and quantitative measures. Endocrine deficits occurred in 61 %, neurological complications in 72 %, and significant school problems in 72 %. All patients had significant deficits in neurocognitive functioning: attention and processing speed was impaired in 79 %, learning and memory in 88 %, language in 56 %, visual perception in 50 %, and executive functions in 64 %. In comparison with healthy controls, social functioning was rated by the patients as the QoL dimension most affected. Parents' ratings were considerably lower than those of the patients. No MB survivor > 18 years of age (n = 12) had a boy- or girlfriend. Because of their treatment, including craniospinal radiotherapy, MB long-time survivors are not only at great risk for neurological, endocrine, and neurocognitive complications, but also of social isolation thereby decreasing self-rated QoL substantially.

Marchiafava-Bignami-like injury of the corpus callosum in an infant

We report on a 16-month-old boy who presented with truncal ataxia and intermittent nystagmus. Magnetic resonance imaging (MRI) at 19 months showed a T (2)-hyperintensity of the splenium and the genu of the corpus callosum with extension into the adjacent frontal white matter. Diffusion tensor imaging (DTI) revealed a corresponding area of restricted diffusion, suggesting cytotoxic oedema. The extent and localisation of the signal abnormalities mimic tissue injury as seen in Marchiafava-Bignami disease (MBD). Metabolic investigations were normal. Follow-up imaging at 24 months showed a similar T (2)-hyperintensity of the corpus callosum and white matter while on DTI the cytotoxic oedema had resolved. Clinically a remaining truncal and gait ataxia, clumsiness and a developmental delay is seen. Goal of this case report is (a) to present a rare case of Marchiafava-Bignami-like injury of the corpus callosum in an infant and (b) to discuss the neuroradiological imaging findings including MRI and DTI.

Leukoencephalopathy with ataxia, hypodontia, and hypomyelination

The authors describe four unrelated girls with a distinctive neurologic disorder with early-onset progressive ataxia and hypodontia with a characteristic pattern of delayed dentition. Cerebral MRI shows hypomyelinated white matter and cerebellar atrophy; 1H-MRS of white matter reveals a marked elevation of myo-inositol.

The first three years of the Swiss Neuropaediatric Stroke Registry (SNPSR): a population-based study of incidence, symptoms and risk factors

We report the results of three years of the population-based, prospective Swiss NeuroPaediatric Stroke Registry (SNPSR) of children (up to 16 years) with childhood arterial ischaemic stroke (AIS1), neonatal stroke (AIS2), or symptomatic sinus venous thrombosis (SVT). Data on risk factors (RF), presentation, diagnostic work-up, localisation, and short-term neurological outcome were collected. 80 children (54 males) have been included, 40 AIS1, 23 AIS2, and 17 SVT. The data presented will be concentrated on AIS. The presentation for AIS1 was hemiparesis in 77% and cerebellar symptoms and seizures in 20%, respectively. AIS2 presented in 83% with seizures and in 38% with abnormality of muscle tone. Two or more RF were detected in 54%, one RF in 35%. The most prominent RF for AIS1 were infections (40%), followed by cardiopathies and coagulopathies (25% each). AIS2 were frequently related to birth problems. Neurological outcomes in AIS1 and AIS2 were moderate/severe in 45 % and 32 %, respectively. The outcome correlated significantly with the size of infarction (p = 0.013) and age at stroke (p = 0.027). The overall mortality was 6%. Paediatric stroke is a multiple risk problem, which leads to important long-term sequelae.

Cerebellar agenesis and diabetes insipidus

We report on a 7-year-old female, born after a normal pregnancy at term, previously referred because of delayed psychomotor development. MRI revealed isolated cerebellar agenesis (CA) with only minute tissue remnants of the anterior vermis/paravermian anterior quadrangular lobes and pontine hypoplasia. The patient demonstrated truncal ataxia, saccadic ocular pursuit and mild gaze evoked nystagmus. At the age of 2.5 years, the girl achieved independent walking, though with a markedly ataxic gait; at the same age diabetes insipidus was recognized and appropriately treated. This association has not been reported before. At the ages of 3.5 and 6.5 years, her developmental quotient (DQ) was 65 and 60, respectively, with a very poor vocabulary and cerebellar dysarthria. The term "agenesis" is problematic as several reports describe considerable cerebellar tissue remnants and may include pontocerebellar hypoplasia. A literature review disclosed only a few patients with CA (defined in a strict sense) diagnosed in vivo by MRI. It is questionable whether asymptomatic CA occurs.

Cerebral actinomycosis before adolescence

In a 10-year-old boy presenting with focal seizures and 6 months later with acute right-sided hemiparesis, the diagnosis of a cerebral abscess due to Actinomyces israelii was established. The immunocompetent child suffered from a complex congenital heart disease with pulmonary arteriovenous shunts and pulmonary hypertension causing mild cyanosis. His parents had been reluctant to agree to neuroimaging investigations resulting in a delayed diagnosis. Despite the long interval between first symptoms and commencement of treatment including neurosurgical excision of the abscess followed by a 4-week course of ceftriaxone, a complete recovery of the hemiparesis was observed. This patient is the first case with cerebral actinomycosis before adolescence reported so far.

Follow-up of a child with hypoacetylaspartia

We provide a 5-year follow-up of a patient previously reported to have no NAA signal on neurospectroscopy. At 8 years this boy was found to have profound neurological dysfunction: he had truncal ataxia, no expressive speech, behaviour abnormalities, secondary microcephaly and cognitive achievements corresponding to less than 12 months of age. He started to have generalized seizures at 5 years 9 months. Although not directly proven we assume an inborn error of NAA metabolism, possibly a defect of the anabolic enzyme L-aspartate N-acetyltransferase (EC 2.3.1.17).

Homozygosity mapping of a third Joubert syndrome locus to 6q23

BACKGROUND

Joubert syndrome (JS) is a recessively inherited disorder characterised by hypotonia at birth and developmental delay, followed by truncal ataxia and cognitive impairment, characteristic neuroimaging findings (cerebellar vermis hypoplasia, "molar tooth sign") and suggestive facial features. JS is clinically heterogeneous with some patients presenting with breathing abnormalities in the neonatal period, oculomotor apraxia, retinal dystrophy, retinal coloboma, ptosis, hexadactyly, and nephronophtisis or cystic dysplastic kidneys. JS is also genetically heterogeneous, with two known loci, on 9q34 (JBTS1) and 11p11-q12 (CORS2), representing only a fraction of cases.

METHODS

A large consanguineous Joubert family (five affected) was analysed for linkage with a marker set covering the entire genome and 16 smaller families were subsequently tested for candidate loci.

RESULTS

We report here the identification of a third locus in 6q23 (JBTS3) from the study of two consanguineous families. LOD score calculation, including the consanguinity loops, gave a maximum value of 4.1 and 2.3 at q = 0 for the two families, respectively.

CONCLUSIONS

Linkage between the disease and the D6S1620-D6S1699 haplotype spanning a 13.1 cM interval is demonstrated. Genotype-phenotype studies indicate that, unlike CORS2, JBTS3 appears not to be associated with renal dysfunction.

Episodic ataxia type 1 with distal weakness: a novel manifestation of a potassium channelopathy

Episodic ataxia type1 (EA1) is an autosomal dominant disorder characterised by episodes of ataxia, dysarthria, tremor and visual disturbances lasting for seconds or minutes, precipitated by physical and emotional stress, startle or sudden movements. In addition there is continuous myokymia. Phenotypic variants such as the combination with epilepsy, shortening of the Achilles tendon in children, transient postural abnormalities in infancy, and a very few patients with longer lasting episodes have been reported. We describe a 10-year-old girl with EA1 who has distal weakness with paresis of the extensors of the feet and prolonged spells of limb stiffness (neuromyotonia) lasting up to 12 hours. A novel single nucleotide change at position 785 T > C that alters a highly conserved residue in the third transmembrane segment of the voltage-gated potassium channel Kv1.1 was found.