A novel de novo truncating variant in a Hungarian patient with CTNNB1 neurodevelopmental disorder

PURPOSE

We aimed to elucidate the underlying disease in a Hungarian family, with only one affected family member, a 16-year-old male Hungarian patient, who developed global developmental delay, cognitive impairment, behavioral problems, short stature, intermittent headaches, recurrent dizziness, strabismus, hypermetropia, complex movement disorder and partial pituitary dysfunction. After years of detailed clinical investigations and careful pediatric care, the exact diagnosis of the patient and the cause of the disease was still unknown.

METHODS

We aimed to perform whole exome sequencing (WES) in order to investigate whether the affected patient is suffering from a rare monogenic disease.

RESULTS

Using WES, we identified a novel, de novo frameshift variant (c.1902dupG, p.Ala636SerfsTer12) of the catenin beta-1 (CTNNB1) gene. Assessment of the novel CTNNB1 variant suggested that it is a likely pathogenic one and raised the diagnosis of CTNNB1 neurodevelopmental disorder (OMIM 615,075).

CONCLUSIONS

Our manuscript may contribute to the better understanding of the genetic background of the recently discovered CTNNB1 neurodevelopmental disorder and raise awareness among clinicians and geneticists. The affected Hungarian family demonstrates that based on the results of the clinical workup is difficult to establish the diagnosis and high-throughput genetic screening may help to solve these complex cases.

Craniofacial features of POLR3-related leukodystrophy caused by biallelic variants in POLR3A, POLR3B and POLR1C

BACKGROUND

RNA polymerase III-related or 4H leukodystrophy (POLR3-HLD) is an autosomal recessive hypomyelinating leukodystrophy characterized by neurological dysfunction, hypodontia and hypogonadotropic hypogonadism. The disease is caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C or POLR3K. Craniofacial abnormalities reminiscent of Treacher Collins syndrome have been originally described in patients with POLR3-HLD caused by biallelic pathogenic variants in POLR1C. To date, no published studies have appraised in detail the craniofacial features of patients with POLR3-HLD. In this work, the specific craniofacial characteristics of patients with POLR3-HLD associated with biallelic pathogenic variants in POLR3A, POLR3B and POLR1C are described.

METHODS

The craniofacial features of 31 patients with POLR3-HLD were evaluated, and potential genotype-phenotype associations were evaluated.

RESULTS

Various craniofacial abnormalities were recognized in this patient cohort, with each individual presenting at least one craniofacial abnormality. The most frequently identified features included a flat midface (61.3%), a smooth philtrum (58.0%) and a pointed chin (51.6%). In patients with POLR3B biallelic variants, a thin upper lip was frequent. Craniofacial anomalies involving the forehead were most commonly associated with biallelic variants in POLR3A and POLR3B while a higher proportion of patients with POLR1C biallelic variants demonstrated bitemporal narrowing.

CONCLUSION

Through this study, we demonstrated that craniofacial abnormalities are common in patients with POLR3-HLD. This report describes in detail the dysmorphic features of POLR3-HLD associated with biallelic variants in POLR3A, POLR3B and POLR1C.

A Recurrent De Novo Variant in EIF2AK2 Causes a Hypomyelinating Leukodystrophy

De novo pathogenic variants in EIF2AK2 have recently been reported as a novel genetic cause of leukoencephalopathy. Here, we describe a male individual who presented in the first year of life with clinical features resembling Pelizaeus-Merzbacher disease (PMD), including nystagmus, hypotonia, and global developmental delay, and which later progressed to include ataxia and spasticity. Brain MRI at the age of two revealed diffuse hypomyelination. This report adds to the limited number of individuals published and further reinforces de novo variants in EIF2AK2 as a molecular cause of a leukodystrophy that clinically and radiologically resembles PMD.

DWI-FLAIR mismatch guided thrombolysis in patients without large-vessel occlusion: real-world data from a comprehensive stroke centre

Introduction

A significant proportion of ischaemic stroke patients present with unknown symptom onset time. DWI-FLAIR mismatch on MRI can help to identify those eligible for thrombolysis. We set out to analyse the short-term efficacy and safety of thrombolysis in a real-world setting.

Methods

A retrospective single-centre observational study was conducted. We collected data between January 2017 and April 2020. Patients with a large vessel occlusion (LVO) were excluded. Outcomes were compared between thrombolysed patients and those who did not receive alteplase due to lack of DWI-FLAIR mismatch or other contraindications. We analysed baseline and discharge NIHSS scores for efficacy and defined good outcome as any neurological improvement (ANI) on the NIHSS. In terms of safety, the presence and severity of intracerebral haemorrhage on follow-up imaging was analysed, and mortality at 90 days assessed.

Results

Seventy-one patients were included in this study, of whom 29 received thrombolysis. Significantly more patients had ANI in the thrombolysed group (OR, 3.16; 95% CI, 1.178-8.479; p = 0.020). In a multivariable logistic regression analysis, only thrombolysis correlated with ANI (OR, 3.051; 95% CI, 1.135-8.206; p = 0.027). Two thrombolysed patients suffered intracerebral haemorrhage (6.90%), of whom one was symptomatic and eventually fatal. We did not find a significant difference in 90-day mortality between the two groups (OR, 0.81, 95% CI, 0.134-4.856; p = 1.000).

Conclusions

Our real-world data demonstrate that thrombolysis based on DWI-FLAIR mismatch in patients without LVO has an early beneficial effect. The rate of intracerebral haemorrhage was similar to this complication reported in large thrombolysis trials with known onset times.

Kynurenic acid and kynurenine aminotransferase are potential biomarkers of early neurological improvement after thrombolytic therapy: A pilot study

BACKGROUND

Biomarkers for predicting treatment response to thrombolysis in acute ischemic stroke are currently lacking. Both, animal models and clinical studies have provided evidence that the kynurenine (KYN) pathway is activated in ischemic stroke.

OBJECTIVES

In our pilot study, we aimed to investigate whether KYN pathway enzymes and metabolites could serve as potential biomarkers for treatment response in the hyperacute phase of ischemic stroke.

MATERIAL AND METHODS

We included 48 acute ischemic stroke patients who received thrombolysis. Blood samples were taken both before and 12 h after treatment. Concentrations of 11 KYN metabolites were determined using ultra-high-performance liquid chromatography-mass spectrometry. To assess the treatment response, we used early neurological improvement (ENI), calculated as the difference between the admission and discharge National Institutes of Health Stroke Scale (NIHSS) scores. We performed receiver operating characteristic (ROC) analysis for KYN pathway metabolites and enzymes that showed a correlation with ENI.

RESULTS

In the samples taken before thrombolysis, significantly lower concentrations of kynurenic acid (KYNA) and kynurenine aminotransferase (KAT) activity were found in patients who had ENI (p = 0.01 and p = 0.002, respectively). According to the ROC analysis, the optimal cut-off value to predict ENI for KYNA was 37.80 nM (sensitivity (SN) 69.2%, specificity (SP) 68.4%) and 0.0127 for KAT activity (SN 92.3%, SP 73.7%).

CONCLUSIONS

Our research is the first clinical pilot study to analyze changes in the KYN pathway in ischemic stroke patients who received thrombolytic treatment. Based on our results, baseline KYNA concentration and KAT activity could serve as potential biomarkers to predict early treatment response to thrombolysis.

Endocrine and Growth Abnormalities in 4H Leukodystrophy Caused by Variants in POLR3A, POLR3B, and POLR1C

CONTEXT

4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date.

OBJECTIVE

To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy.

DESIGN

An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated.

SETTING

This was a multicenter retrospective study using information collected from 3 predominant centers.

PATIENTS

A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included.

MAIN OUTCOME MEASURES

Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts.

RESULTS

The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients.

CONCLUSIONS

Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder.

Tremor as an early sign of hereditary spastic paraplegia due to mutations in ALDH18A1

BACKGROUND

The ALDH18A1 gene is located at 10q24.1 and encodes delta-1-pyrroline-5-carboxylate synthetase (P5CS), a mitochondrial bifunctional enzyme that catalyzes the first two steps in de novo biosynthesis of proline, ornithine, citrulline, and arginine. ALDH18A1-related disorders have been classified into four groups, such as autosomal dominant and recessive hereditary spastic paraplegia (SPG9A and SPG9B, respectively), as well as autosomal dominant and recessive cutis laxa (ADCL3 and ARCL3A, respectively). Neurodegeneration is a characteristic feature of all groups.

CASE REPORT

Here, we report a girl with compound heterozygous disease-causing variants (c.-28-2A>G and c.383G>A, p.Arg128His) in the ALDH18A1 gene, revealed by whole exome sequencing. The c.-28-2A>G variant in intron 1, inherited from the mother, is a novel mutation, while the c.383G>A variant in exon 4, inherited from the father, has already been reported. The patient presented with vigorous infantile tremor preceding progressive spastic paraplegia. Dysmorphic features included elongated face, deep-set ears, upturned nose, long philtrum and pointed chin. Intrauterine and postnatal growth retardation, microcephaly, global developmental delay and profound intellectual disability were also noticed. Blood fasting ammonia level, plasma proline, ornithine and arginine levels were normal, while citrulline level was slightly decreased. Brain MRI revealed moderate hypoplasia of the corpus callosum and reduction of white matter volume.

CONCLUSIONS

The patient represents SPG9B, a rare form of autosomal recessive hereditary spastic paraplegias. The early onset tremor, preceding lower limb spasticity appears to be a unique early manifestation of neurodegeneration in this case.

A Novel Homozygous Frameshift WDR81 Mutation associated with Microlissencephaly, Corpus Callosum Agenesis, and Pontocerebellar Hypoplasia

Microlissencephaly is a brain malformation characterized by microcephaly and extremely simplified gyral pattern. It may be associated with corpus callosum agenesis and pontocerebellar hypoplasia. In this case report, we described two siblings, a boy and a girl, with this complex brain malformation and lack of any development. In the girl, exome sequencing of a gene set representing 4,813 genes revealed a homozygous AG deletion in exon 7 of the WDR81 gene, leading to a frameshift (c.4668_4669delAG, p.Gly1557AspfsTer16). The parents were heterozygous for this mutation. The boy died without proper genetic testing. Our findings expand the phenotypic and genotypic spectrum of WDR81 gene mutations.

Clinical spectrum of POLR3-related leukodystrophy caused by biallelic POLR1C pathogenic variants

Objective

To determine the clinical, radiologic, and molecular characteristics of RNA polymerase III-related leukodystrophy (POLR3-HLD) caused by biallelic POLR1C pathogenic variants.

Methods

A cross-sectional observational study involving 25 centers worldwide was conducted. Clinical and molecular information was collected on 23 unreported and previously reported patients with POLR3-HLD and biallelic pathogenic variants in POLR1C. Brain MRI studies were reviewed.

Results

Fourteen female and 9 male patients aged 7 days to 23 years were included in the study. Most participants presented early in life (birth to 6 years), and motor deterioration was seen during childhood. A notable proportion of patients required a wheelchair before adolescence, suggesting a more severe phenotype than previously described in POLR3-HLD. Dental, ocular, and endocrine features were not invariably present (70%, 50%, and 50%, respectively). Five patients (22%) had a combination of hypomyelinating leukodystrophy and abnormal craniofacial development, including 1 individual with clear Treacher Collins syndrome (TCS) features. Brain MRI revealed hypomyelination in all cases, often with areas of pronounced T2 hyperintensity corresponding to T1 hypointensity of the white matter. Twenty-nine different pathogenic variants (including 12 new disease-causing variants) in POLR1C were identified.

Conclusions

This study provides a comprehensive description of POLR3-HLD caused by biallelic POLR1C pathogenic variants based on the largest cohort of patients to date. These results suggest distinct characteristics of POLR1C-related disorder, with a spectrum of clinical involvement characterized by hypomyelinating leukodystrophy with or without abnormal craniofacial development reminiscent of TCS.

P6542Early Prolonged Ambulatory Cardiac monitoring in Stroke (EPACS): an open-label randomised controlled trial and economic evaluation

Background

Cardioembolism in paroxysmal atrial fibrillation (PAF) is a preventable cause of transient ischaemic attack (TIA) or ischaemic stroke, however, due its transient nature, a short-duration Holter monitor may miss a significant proportion of events.

Methods

We conducted an open-label randomised controlled trial of cardiac monitoring after a TIA or ischaemic stroke comparing a 14-day ECG monitoring patch with short-duration Holter monitoring for the detection of PAF. The primary outcome was the detection of one or more episodes of ECG-documented PAF lasting at least 30 seconds within 90 days in each of the study arms.

A budget impact analysis from the healthcare perspective was performed to assess the theoretical economic implications of the patch-based service versus Holter monitoring. Based on the AF detection rates found in this study, Hospital Episode Statistics data for the incidence of stroke and TIA (October 2016-September 2017) and National Health Service reference costs, the cost-effectiveness of the patch-based service versus Holter monitoring was calculated. The Sentinel Stroke National Audit Programme estimate of £13,452 was used as the mean year one direct medical cost of a stroke.

Results

From February 2016 through February 2017, 43 (76.8%) of the 56 patients assigned to the patch-based monitoring group and 47 (78.3%) of the 60 patients assigned to the short-duration Holter monitoring group had successful monitor placement with 90 days of follow-up (Figure 1). Of the 26 protocol failures between the two groups, 23 (88.5%) were due to patient refusal for outpatient short-duration Holter monitor placement, whilst only 1 (3.8%) was due to unsuccessful patch placement. The rate of detection of PAF at 90 days was 16.3% in the patch-based monitoring group (7 patients) compared to 2.1% in the short-duration Holter monitoring group (1 patient), with an odds ratio of 8.9 (95% CI 1.1–76.0; P=0.026).

Implementation of the patch-based service at our hospital would result in 10.8 more strokes avoided per year compared to current practice with short-duration Holter monitoring. This would equate to a yearly saving in direct medical costs of £57,481, increasing to £106,342 over 5 years. When social care costs are included, incremental savings of £154,716 can be achieved in the first year and £410,449 at 5 years. In addition, an analysis of the potential reduction in outpatient follow-up appointment costs resulted in a further saving of £56,149, giving a total potential saving of £113,630 over the first year with the use of the patch-based service compared to short-duration Holter monitoring, increasing to £162,491 over 5 years.

Figure 1. Study participant flowchart

Conclusions

Early, prolonged, patch-based monitoring after an index stroke or TIA is superior to short-duration Holter monitoring in the detection of PAF and likely cost-effective for preventing recurrent strokes.

Acknowledgement/Funding

Bristol-Myers Squibb-Pfizer alliance (Grant Number CV185-475)

Co-occurrence of mutations in FOXP1 and PTCH1 in a girl with extreme megalencephaly, callosal dysgenesis and profound intellectual disability

Heterozygous disruptions in FOXP1 are responsible for developmental delay, intellectual disability and speech deficit. Heterozygous germline PTCH1 disease-causing variants cause Gorlin syndrome. We describe a girl with extreme megalencephaly, developmental delay and severe intellectual disability. Dysmorphic features included prominent forehead, frontal hair upsweep, flat, wide nasal bridge, low-set, abnormally modelled ears and post-axial cutaneous appendages on the hands. Brain MRI showed partial agenesis of the corpus callosum and widely separated leaves of the septum pellucidum. Exome sequencing of a gene set representing a total of 4813 genes with known relationships to human diseases revealed an already known heterozygous de novo nonsense disease-causing variant in FOXP1 (c.1573C>T, p.Arg525Ter) and a heterozygous novel de novo frameshift nonsense variant in PTCH1 (c.2834delGinsAGATGTTGTGGACCC, p.Arg945GlnfsTer22). The composite phenotype of the patient seems to be the result of two monogenic diseases, although more severe than described in conditions due to disease-causing variants in either gene.

Mutations of AKT3 are associated with a wide spectrum of developmental disorders including extreme megalencephaly

Mutations of genes within the phosphatidylinositol-3-kinase (PI3K)-AKT-MTOR pathway are well known causes of brain overgrowth (megalencephaly) as well as segmental cortical dysplasia (such as hemimegalencephaly, focal cortical dysplasia and polymicrogyria). Mutations of the AKT3 gene have been reported in a few individuals with brain malformations, to date. Therefore, our understanding regarding the clinical and molecular spectrum associated with mutations of this critical gene is limited, with no clear genotype-phenotype correlations. We sought to further delineate this spectrum, study levels of mosaicism and identify genotype-phenotype correlations of AKT3-related disorders. We performed targeted sequencing of AKT3 on individuals with these phenotypes by molecular inversion probes and/or Sanger sequencing to determine the type and level of mosaicism of mutations. We analysed all clinical and brain imaging data of mutation-positive individuals including neuropathological analysis in one instance. We performed ex vivo kinase assays on AKT3 engineered with the patient mutations and examined the phospholipid binding profile of pleckstrin homology domain localizing mutations. We identified 14 new individuals with AKT3 mutations with several phenotypes dependent on the type of mutation and level of mosaicism. Our comprehensive clinical characterization, and review of all previously published patients, broadly segregates individuals with AKT3 mutations into two groups: patients with highly asymmetric cortical dysplasia caused by the common p.E17K mutation, and patients with constitutional AKT3 mutations exhibiting more variable phenotypes including bilateral cortical malformations, polymicrogyria, periventricular nodular heterotopia and diffuse megalencephaly without cortical dysplasia. All mutations increased kinase activity, and pleckstrin homology domain mutants exhibited enhanced phospholipid binding. Overall, our study shows that activating mutations of the critical AKT3 gene are associated with a wide spectrum of brain involvement ranging from focal or segmental brain malformations (such as hemimegalencephaly and polymicrogyria) predominantly due to mosaic AKT3 mutations, to diffuse bilateral cortical malformations, megalencephaly and heterotopia due to constitutional AKT3 mutations. We also provide the first detailed neuropathological examination of a child with extreme megalencephaly due to a constitutional AKT3 mutation. This child has one of the largest documented paediatric brain sizes, to our knowledge. Finally, our data show that constitutional AKT3 mutations are associated with megalencephaly, with or without autism, similar to PTEN-related disorders. Recognition of this broad clinical and molecular spectrum of AKT3 mutations is important for providing early diagnosis and appropriate management of affected individuals, and will facilitate targeted design of future human clinical trials using PI3K-AKT pathway inhibitors.

Mutations in KIAA0586 Cause Lethal Ciliopathies Ranging from a Hydrolethalus Phenotype to Short-Rib Polydactyly Syndrome

KIAA0586, the human ortholog of chicken TALPID3, is a centrosomal protein that is essential for primary ciliogenesis. Its disruption in animal models causes defects attributed to abnormal hedgehog signaling; these defects include polydactyly and abnormal dorsoventral patterning of the neural tube. Here, we report homozygous mutations of KIAA0586 in four families affected by lethal ciliopathies ranging from a hydrolethalus phenotype to short-rib polydactyly. We show defective ciliogenesis, as well as abnormal response to SHH-signaling activation in cells derived from affected individuals, consistent with a role of KIAA0586 in primary cilia biogenesis. Whereas centriolar maturation seemed unaffected in mutant cells, we observed an abnormal extended pattern of CEP290, a centriolar satellite protein previously associated with ciliopathies. Our data show the crucial role of KIAA0586 in human primary ciliogenesis and subsequent abnormal hedgehog signaling through abnormal GLI3 processing. Our results thus establish that KIAA0586 mutations cause lethal ciliopathies.

Nemaline myopathy type 2 (NEM2): two novel mutations in the nebulin (NEB) gene

Nemaline myopathy is a type of the heterogeneous group of congenital myopathies. Generalized hypotonia, weakness, and delayed motor development are the main clinical features of the typical congenital form. Histopathology shows characteristic nemaline rods in the muscle biopsy. Mutations in at least 7 genes, including nebulin gene (NEB), proved to be responsible for this muscle disease. We present a boy with nemaline myopathy type 2 (NEM2) caused by compound heterozygosity for 2 novel mutations, a deletion and a duplication in the NEB gene. The deletion was inherited from the father and the duplication from the mother. Testing all family members supports genetic counseling.

Spectrum of neurodevelopmental disabilities: a cohort study in hungary

The spectrum of neurodevelopmental disabilities was studied in a cohort of patients in Hungary. A search for etiologies and assessment of the degree of intellectual disability were carried out. The study included 241 (131 boys) patients. Disability occurred without any prenatal, perinatal, and/or neonatal adverse events in 167 patients. They were classified into the following subgroups: genetic syndromes with recognized etiology, global developmental delay/intellectual disability in association with dysmorphic features but unknown etiology, global developmental delay/intellectual disability without dysmorphic features and recognized etiology, brain malformations, inborn errors of metabolism, leukoencephalopathies, epileptic syndromes, developmental language impairment, and neuromuscular disorders. Adverse events occurred in 74 children classified into subgroups such as cerebral palsy after delivery preterm or at term, and disabilities without cerebral palsy. The etiology was identified in 66.4%, and genetic diagnosis was found in 19.5%. Classification of neurodevelopmental disorders contribute to etiological diagnosis, proper rehabilitation, and genetic counseling.

Clinical presentation and outcome in a series of 88 patients with the cblC defect

The cblC defect is the most common inborn error of vitamin B12 metabolism. Despite therapeutic measures, the long-term outcome is often unsatisfactory. This retrospective multicentre study evaluates clinical, biochemical and genetic findings in 88 cblC patients. The questionnaire designed for the study evaluates clinical and biochemical features at both initial presentation and during follow up. Also the development of severity scores allows investigation of individual disease load, statistical evaluation of parameters between the different age of presentation groups, as well as a search for correlations between clinical endpoints and potential modifying factors.

RESULTS

No major differences were found between neonatal and early onset patients so that these groups were combined as an infantile-onset group representing 88 % of all cases. Hypotonia, lethargy, feeding problems and developmental delay were predominant in this group, while late-onset patients frequently presented with psychiatric/behaviour problems and myelopathy. Plasma total homocysteine was higher and methionine lower in infantile-onset patients. Plasma methionine levels correlated with "overall impression" as judged by treating physicians. Physician's impression of patient's well-being correlated with assessed disease load. We confirmed the association between homozygosity for the c.271dupA mutation and infantile-onset but not between homozygosity for c.394C>T and late-onset. Patients were treated with parenteral hydroxocobalamin, betaine, folate/folinic acid and carnitine resulting in improvement of biochemical abnormalities, non-neurological signs and mortality. However the long-term neurological and ophthalmological outcome is not significantly influenced. In summary the survey points to the need for prospective studies in a large cohort using agreed treatment modalities and monitoring criteria.

Early detection of Angelman syndrome resulting from de novo paternal isodisomic 15q UPD and review of comparable cases

Background

Angelman syndrome is a rare neurogenetic disorder that results in intellectual and developmental disturbances, seizures, jerky movements and frequent smiling. Angelman syndrome is caused by two genetic disturbances: either genes on the maternally inherited chromosome 15 are deleted or inactivated or two paternal copies of the corresponding genes are inherited (paternal uniparental disomy). A 16-month-old child was referred with minor facial anomalies, neurodevelopmental delay and speech impairment. The clinical symptoms suggested angelman syndrome. The aim of our study was to elucidate the genetic background of this case.

Results

This study reports the earliest diagnosed angelman syndrome in a 16-month-old Hungarian child. Cytogenetic results suggested a de novo Robertsonian-like translocation involving both q arms of chromosome 15: 45,XY,der(15;15)(q10;q10). Molecular genetic studies with polymorphic short tandem repeat markers of the fibrillin-1 gene, located in the 15q21.1, revealed that both arms of the translocated chromosome were derived from a single paternal chromosome 15 (isodisomy) and led to the diagnosis of angelman syndrome caused by paternal uniparental disomy.

Conclusions

AS resulting from paternal uniparental disomy caused by de novo balanced translocation t(15q;15q) of a single paternal chromosome has been reported by other groups. This paper reviews 19 previously published comparable cases of the literature. Our paper contributes to the deeper understanding of the phenotype-genotype correlation in angelman syndrome for non-deletion subclasses and suggests that patients with uniparental disomy have milder symptoms and higher BMI than the ones with other underlying genetic abnormalities.

Congenital myasthenic syndromes and transient myasthenia gravis

Hypotonia in the neonatal period and early infancy is a common clinical finding. It can be caused by various heterogeneous disorders of different origin which might lead to diagnostic difficulties. Disorders of the neuromuscular junction, such as congenital myasthenic syndromes and neonatal transient myasthenia gravis are among the aetiologies. We report on a case of congenital myasthenia caused by mutation in the long cytoplasmic loop of the epsilon subunit of the acetylcholine receptor and a neonate of a myasthenic mother diagnosed with transient myasthenia gravis.

Birth prevalence of neural tube defects: a population-based study in South-Eastern Hungary

PURPOSE

Primary prevention by periconceptional folic acid supplementation can significantly reduce the risk of neural tube defects. EUROCAT, the European network of population-based registries for the epidemiologic surveillance of congenital anomalies, lacks sufficient data on the birth prevalence of neural tube defects in Hungary before and after the promotion of primary prevention by folic acid. Our aims were to compare the birth prevalence of neural tube defects (myelomeningocele, anencephaly and encephalocele) over two 12-year periods in South-Eastern Hungary. Further aims were to compare our data to those ones in other areas in Europe.

METHODS

Data were collected from the databases of the Department of Hungarian Congenital Abnormality Registry. The total and live birth prevalence rate of neural tube defects were calculated and compared over 1980-1991 and 1994-2005. In addition, the trends in the total birth prevalence, the number of live births and terminations for and stillbirths with neural tube defects were analysed throughout the period of 1994-2005.

RESULTS

A significant decline was found in the total and live birth prevalence of myelomeningocele, anencephaly and encephalocele over 1994-2005 compared to the period of 1980-1991. The total birth prevalence of neural tube defects, however, showed a trend of increase after 1994, with declining number of live births and increasing number of terminations for neural tube defects.

CONCLUSION

Public health measures are warranted in order to replace termination of pregnancy with primary prevention in South-Eastern Hungary.

Lissencephaly and band heterotopia: LIS1, TUBA1A, and DCX mutations in Hungary

The spectrum of lissencephaly ranges from absent (agyria) or decreased (pachygyria) convolutions to less severe malformation known as subcortical band heterotopia. Mutations involving LIS1 and TUBA1A result in the classic form of lissencephaly, whereas mutations of the DCX gene cause lissencephaly in males and subcortical band heterotopia in females. This report describes the clinical manifestations and imaging and genetic findings in 2 boys with lissencephaly and a girl with subcortical band heterotopia. An ovel mutation (c.83_84delAT, p.Tyr28Phefs*31) was identified in LIS1 in 1 of the boys with lissencephaly and another novel mutation (c.200delG, p.Ile68Leufs*87) was found in DCX in the girl with subcortical band heterotopia. The mutations appeared in the first half of the genes and are predicted to result in truncated proteins. A mutation was found in the TUBA1A gene (c.1205G>A, p.Arg402His) in the other boy. This mutation affects the folding of tubulin heterodimers, changing the interactions with proteins that bind microtubules.

Holoprosencephaly in hungary: birth prevalence and clinical spectrum

A retrospective population based survey of patients born with holoprosencephaly in South-Eastern Hungary between July 1, 1992 and June 30, 2006 was performed. All live birth cases with craniofacial and non-craniofacial abnormalities were included in the study. A total of 9 patients (5 boys and 4 girls) were found with holoprosencephaly among 185 486 live births, which correspond to a birth prevalence of 0.49 per 10,000 live births (95% confidence interval [CI]: 0.17-0.80). These figures were similar to those ones found in New York State and several European regions. In our series one newborn had trisomy 13. Eight patients did not have chromosomal abnormalities on routine testing, 4 of them had craniofacial abnormalities only and another 4 showed non-craniofacial anomalies as well. Three patients died in the neonatal period and another one in childhood. Patients surviving the neonatal period had intellectual and motor handicap, and epilepsy.

Corpus callosum anomalies: birth prevalence and clinical spectrum in Hungary

Data regarding the epidemiology of callosal anomalies are contradictory. We performed a population-based retrospective survey to study the birth prevalence and clinical features of agenesis/hypoplasia of the corpus callosum and accompanying central nervous system and somatic abnormalities in southeastern Hungary between July 1, 1992 and June 30, 2006. Among 185,486 live births, 38 patients (26 boys and 12 girls) manifested agenesis/hypoplasia of the corpus callosum, corresponding to a prevalence of 2.05 per 10,000 live births (95% confidence interval, 1.4-2.7). Callosal anomalies were isolated in 18 patients, and were associated with other central nervous system malformations in five children. Both central nervous system and noncentral nervous system abnormalities were evident in seven patients, whereas callosal dysgenesis was accompanied only by somatic anomalies in eight children. Five of 18 patients with isolated agenesis/hypoplasia of the corpus callosum remained asymptomatic. Developmental delay, intellectual disability, or epilepsy occurred in all patients, except one, when callosal anomalies were combined with other brain or somatic abnormalities. Five patients with multiplex malformations died. Callosal anomalies form a clinically significant and relatively frequent group of central nervous system malformations.

Development of visual contour integration in children with migraine without aura

Introduction: As migraine attacks pose insult to cerebral circulation and ion homeostasis, migraine has the potential to interfere with the development of different brain structures, producing functional deficits. It is known that visual contour integration (CI) is a function with a protracted development. Therefore, we sought to establish whether migraine interferes with its development.

Methods: Forty-eight migraineurs (without aura) and 48 age- and sex-matched controls participated in the study, divided into three cohorts by age. Stimuli were presented on cards with a contour consisting of Gabor patches embedded in random noise. Difficulty was varied by the manipulation of relative noise density. The task was to identify and show the contour.

Results: A significant difference was found between the performance of migraineurs and controls in the 10–14-year-old and 15–18-year-old cohorts ( p < 0.05). Development between all three cohorts was significant in the control group ( p < 0.017), while it was not significant in migraineurs between 6 and 14 years. Correlation between age and CI threshold was stronger in controls than in migraineurs.

Conclusion: Children with paediatric migraine exhibited a less marked development in the Gabor patch-based CI task.

Epidemiology and clinical spectrum of schizencephaly in south-eastern Hungary

The epidemiology and clinical spectrum of schizencephaly in south-eastern Hungary have been surveyed in a retrospective population-based study. A total of 10 patients (6 boys and 4 girls) were found with schizencephaly among 185 486 live births in a period of 14 years (July 1, 1992 to June 30, 2006), which means a birth prevalence of 0.54 per 10 000 (95% confidence interval [CI]: 0.20-0.87). The schizencephaly was unilateral in 7 cases (with closed lips in 5 and open lips in 2 patients) and bilateral in 3 children (with closed lips in 2 and open lips in 1). The septum pellucidum was absent in 5 cases; however, optic nerve hypoplasia was not found in these patients. Delayed development and intellectual disability were observed in all patients, except 2 with unilateral closed lip schizencephaly. Epilepsy was diagnosed in 3 patients (2 with unilateral and 1 with bilateral schizencephaly).

Primary microcephaly in Hungary: epidemiology and clinical features

AIM

To describe the population-based epidemiological characteristics and clinical features of primary microcephaly in Hungary.

METHODS

A retrospective survey of patients born with microcephaly in a region (Dél-Alföld - South Great Plain) in Hungary between July 1, 1992 and June 30, 2006 was performed. Patients with microcephaly and without any environmental or obstetric risk factors and/or dysmorphism (primary microcephaly) were included in the study. The birth prevalence of primary microcephaly per 10,000 live births was calculated.

RESULTS

Ten patients (8 girls and 2 boys) were found with primary microcephaly among 185,486 live births, which corresponds to a birth prevalence of 0.54 per 10,000 live births (95% confidence interval: 0.20-0.87). Developmental delay and intellectual disability were the main clinical features. Dyskinesia was seen in one and epilepsy was diagnosed in two patients. The MRI revealed simplified gyral pattern in all patients.

CONCLUSION

Primary microcephaly is a very rare brain malformation, although the birth prevalence found in this survey is slightly higher than the few figures published earlier. As more and more genes and mutations responsible for primary microcephaly are discovered, the ascertainment of these rare cases is mandatory to provide the parents with genetic counselling.

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.

Bilateral operculum syndrome in childhood

We describe 3 patients with bilateral operculum syndrome. They presented with various degrees of suprabulbar (pseudobulbar) signs in addition to delay in cognitive, motor, and speech development in 2 children and developmental language disorder in the third one. A patient with schizencephaly in the left perisylvian area and contralateral polymicrogyria had spastic hemiparesis on the right side, whereas another patient showed bilateral underdevelopment of the opercula in association with axial hypotonia and spastic diplegia. Both of them had epileptiform discharges on the electroencephalogram without clinical manifestations of seizures. The magnetic resonance imaging of the third child with developmental language disorder was normal; however, his electroencephalogram showed frequent bilateral subclinical centrotemporal epileptiform discharges, probably responsible for the speech delay. Structural or functional involvement of the opercula bilaterally was a common finding in all the 3 patients and they had symptoms similar to those described in the developmental type of Foix-Chavany-Marie and Worster-Drought syndromes.

Refining the phenotype of alpha-1a Tubulin (TUBA1A) mutation in patients with classical lissencephaly

Mutations in the alpha-1a Tubulin (TUBA1A) gene have recently been found to cause cortical malformations resemblant of classical lissencephaly but with a specific combination of features. To date, TUBA1A mutations have been described in five patients and three foetuses. Our aims were to establish how common TUBA1A mutations are in patients with lissencephaly and to contribute to defining the phenotype associated with TUBA1A mutation. We performed mutation analysis in the TUBA1A gene in 46 patients with classical lissencephaly. In 44 of the patients, mutations in the LIS1 and/or DCX genes had previously been excluded; in 2 patients, mutation analysis was only performed in TUBA1A based on magnetic resonance imaging (MRI) findings. We identified three new mutations and one recurrent mutation in five patients with variable patterns of lissencephaly on brain MRI. Four of the five patients had congenital microcephaly, and all had dysgenesis of the corpus callosum and cerebellar hypoplasia, and variable cortical malformations, including subtle subcortical band heterotopia and absence or hypoplasia of the anterior limb of the internal capsule. We estimate the frequency of mutation in TUBA1A gene in patients with classical lissencephaly to be approximately 4%, and although not as common as mutations in the LIS1 or DCX genes, mutation analysis in TUBA1A should be included in the molecular genetic diagnosis of classical lissencephaly, particularly in patients with the combination of features highlighted in this paper.

L-2-hydroxyglutaric aciduria: identification of ten novel mutations in the L2HGDH gene

L-2-hydroxyglutaric aciduria (L-2-HGA) is a metabolic disease with an autosomal recessive mode of inheritance. It was first reported in 1980. Patients with this disease have mutations in both alleles of the L2HDGH gene. The clinical presentation of individuals with L-2-HGA is somewhat variable, but affected individuals typically suffer from progressive neurodegeneration. Analysis of urinary organic acids reveals an increased signal of 2-hydroxyglutaric acid, mainly as the L-enantiomer. L-2-HGA is known to occur in individuals of various ethnic backgrounds, but up to now mutation analysis has been mainly focused on patients of Turkish and Portuguese origin. This led us to confirm the diagnosis on the DNA level and undertake the corresponding mutation analysis in individuals of diverse ethnicity previously diagnosed with L-2-HGA on the basis of urinary metabolites and clinical/neuroimaging data. In 24 individuals from 17 families with diverse ethnic and geographic origins, 13 different mutations were found, 10 of which have not been reported previously. At least eight of the patients were compound heterozygotes. The identification of two mutations (c.751C > T and c.905C > T in exon 7) in patients with different origins supports the view that they occurred independently in different families. In contrast, the mutation c.788C > T was detected in all six Venezuelan patients originating from the same Caribbean island of Margarita, but not in other patients, thus rendering a founder effect likely. None of the mutations was found in the control population, indicating that they are most probably causative. Mutation analysis may improve the quality of diagnosis and prenatal diagnosis of L-2-HGA.

[Myotubular myopathy. Case report and review of the literature]

The first Hungarian report of a case of myotubular myopathy is presented here, which is a recessive congenital disorder linked to X chromosome. The patient presented at birth with severe hypotonia, weak spontaneous movements, arthrogryposis and respiratory insufficiency. The biopsy showed the appearance of myotubular myopathy. The diagnosis was further confirmed by genetic analysis revealing a novel frameshift mutation (1314-1315insT) of the myotubularin-coding MTM1 gene.

Effects of citalopram and fluoxetine on the corticocerebral blood flow in conscious rabbits

Depression, which is associated with an increased incidence of vascular events, frequently occurs following stroke. Selective serotonin reuptake inhibitory drugs (SSRIs) as antidepressants, are well tolerated, and also seem to be effective in post-stroke depression. The aim of this study was to investigate the effects of the SSRIs citalopram and fluoxetine, on the corticocerebral blood flow (cCBF) in rabbits with unilateral carotid occlusion induced cerebral ischemia. The cCBF was measured by the hydrogen clearance technique. After determination of the mean baseline cCBF, the effects of individual doses (0.1, 0.3 and I mg/kg) of citalopram or fluoxetine on the cCBF were investigated. Following the induction of an impaired cCBF, the changes in cCBF after drug treatments in this condition were likewise measured. The mean arterial blood pressure (MABP) and the heart rate (HR) from the electrocardiogram (ECG) were also determined. Neither citalopram nor fluoxetine influenced the cCBF in the control group. Fluoxetine improved the cCBF only very slightly in the ischemic animals. In contrast, all the doses of citalopram exerted pronounced and dose-dependent cCBF-increasing effects in the animals with unilateral carotid occlusion (maximal mean ACBF: 10, 16 and 27 ml/min/100 g tissue). The HR was decreased in both groups. Only citalopram treatment led to a slight MABP-decreasing effect. Besides enhancement of the serotonergic transmission in the brain, the cCBF-increasing effect of citalopram under ischemic conditions may be of benefit in post-stroke and vascular depression.

X-linked myotubular myopathy: report of a case with novel mutation

Myotubular myopathy is a well-defined entity within the centronuclear myopathy subgroup of congenital myopathies. The authors present a patient with the most severe X-linked recessive type (XLMTM). A baby boy presented at birth with severe hypotonia, weak spontaneous movements, arthrogryposis, and respiratory insufficiency. Muscle biopsy showed features of myotubular myopathy. The diagnosis was confirmed and further specified by genetic analysis, revealing a novel frameshift mutation (1314-1315insT) of the myotubularin-coding MTM1 gene. This case underlines the importance of interdisciplinary analysis of congenital muscle diseases, including histomorphological and genetic investigations.

[Haemodynamic instability induced by carotid stent implantation]

Intravascular stent implantation is an attractive therapy for carotid artery stenosis. Severe complications of the interventional procedure however include stroke and death.

AIMS

It has been suggested, that episodes of temporary bradycardia and hypotension upon balloon inflation could be related to adverse outcome.

METHODS

In order to assess the significance of episodic haemodynamic instability 24 consecutive patients were continuously monitored during intravascular intervention. Heart rate and blood pressure variability parameters of the patients, and indices of spontaneous baroreflex sensitivity were determined prior to the procedures. The authors have assessed the potential correlation between the autonomic markers recorded on baseline and the subsequent occurrence of reflex mediated haemodynamic instability.

RESULTS

The authors observations confirmed that bradycardia and hypotension occurs frequently at the time of stent after-dilation. Pauses in excess of 3 seconds occurred in 29% of patients. Atropine was administered at 7 instances. The magnitude of systolic blood pressure drop was greater among patients with pauses, however substantial pressure drop was seen among those without pauses as well. No severe complications were seen. Heart rate variability and spontaneous baroreflex sensitivity were reduced in the whole studied population, allowing no prediction of episodes with bradycardia and hypotension.

CONCLUSION

The authors findings indicate that reflex mediated haemodynamic instability induced by carotid artery intervention is a benign phenomenon. Analysis of autonomic markers is of limited value in this patient population.

A novel locus for hereditary spastic paraplegia with thin corpus callosum and epilepsy

BACKGROUND

Hereditary spastic paraplegia (HSP) are classified clinically as pure when progressive spasticity occurs in isolation or complicated when other neurologic abnormalities are present. At least 22 genetic loci have been linked to HSP, 8 of which are autosomal recessive (ARHSP). HSP complicated with the presence of thin corpus callosum (HSP-TCC) is a common subtype of HSP. One genetic locus has been identified on chromosome 15q13-q15 (SPG11) for HSP-TCC, but some HSP-TCC families have not been linked to this locus.

METHODS

The authors characterized two families clinically and radiologically and performed a genome-wide scan and linkage analysis.

RESULTS

The two families had complicated ARHSP. The affected individuals in Family A had thin corpus callosum and mental retardation, whereas in Family B two of three affected individuals had epilepsy. In both families linkage analysis identified a locus on chromosome 8 between markers D8S1820 and D8S532 with the highest combined lod score of 7.077 at marker D8S505. This 9 cM interval located on 8p12-p11.21 represents a new locus for ARHSP-TCC. Neuregulin and KIF13B genes, located within this interval, are interesting functional candidate genes for this HSP form.

CONCLUSION

Two consanguineous families with complicated autosomal recessive hereditary spastic paraplegia were clinically characterized and genetically mapped to a new locus on 8p12-p11.21.

Hippocampal dysgenesis associated with temporal lobe hypoplasia and arachnoid cyst of the middle cranial fossa

We describe two children with left hippocampal dysgenesis in association with temporal lobe hypoplasia and arachnoid cyst of the middle cranial fossa. The hippocampus showed an abnormal globular shape and blurred internal structure in both patients. One of the patients had juvenile myoclonic epilepsy without evidence of seizure onset in the abnormal temporal region. The other patient did not have epilepsy; however, he showed developmental language disorder with a probable relationship to the left temporal abnormalities.

Spectrum of malformations of the hindbrain (cerebellum, pons, and medulla) in a cohort of children with high rate of parental consanguinity

We review 25 patients with a spectrum of hindbrain (cerebellum, pons, and medulla) malformations from a cohort of children with high parental consanguinity rate. Twenty-three of the 25 patients were born to consanguineous parents. The patients were classified in four groups. Eleven patients of 6 families had malformation of the hindbrain and midbrain with molar tooth sign (10 patients of 5 families with typical Joubert syndrome), 5 patients showed severe supratentorial anomalies in addition to the hindbrain malformations, 5 patients had pontocerebellar or cerebellar hypoplasia with anterior horn cell disease in the spinal cord (spinal muscular atrophy), and 4 patients showed malformations affecting predominantly the hindbrain without substantial involvement of other systems. A locus for Joubert syndrome was previously identified on chromosome 9q34.3 in two families, and a second locus on chromosome 11p12-q13.3 in another family. A third Joubert syndrome locus has been mapped at 6q23 and a mutation in the AHI1 gene at this site has been found recently in a further family from this cohort. Delineation of homogeneous subgroups of patients with hindbrain malformations and molecular genetic analysis of these groups may lead to identification of further loci, genes and mutations responsible for the malformations.

Distinguishing the four genetic causes of Jouberts syndrome-related disorders

Jouberts syndrome-related disorders are a group of recessively inherited conditions showing cerebellar vermis hypoplasia and the molar tooth sign of the midbrain-hindbrain junction. Recent analyses have suggested at least three loci, JBTS1 (9q34.3), -2 (11p11.2-q12.3), and -3 (6q23), but the phenotypic spectrum associated with each locus has not been delineated. In addition, deletions of the NPHP1 gene, usually responsible for isolated juvenile nephronophthisis, are occasionally encountered among Jouberts syndrome-related disorder patients. Here, we describe four novel families showing evidence of linkage to two of these loci, provide a 3.6Mb refinement of the JBTS2 locus, and perform a detailed comparison of all linked families identified so far, to define the clinical and radiographical hallmarks for each genetic condition. We find that JBTS1 and -3 primarily show features restricted to the central nervous system, with JBTS1 showing largely pure cerebellar and midbrain-hindbrain junction involvement, and JBTS3 displaying cerebellar, midbrain-hindbrain junction, and cerebral cortical features, most notably polymicrogyria. Conversely, JBTS2 is associated with multiorgan involvement of kidney, retina, and liver, in addition to the central nervous system features, and results in extreme phenotypic variability. This provides a useful framework for genetic testing strategies and prediction of which patients are most likely to experience development of systemic complications.

Electroencephalography, Doppler vascular scanning, and single photon emission computed tomography in a child with hydranencephaly and intractable seizures

In a child with hydranencephaly and refractory seizures, the electroencephalogram showed a flat isoelectric pattern with no significant slow waves or epileptiform activity; cranial computed tomography, magnetic resonance imaging, Doppler vascular scanning, and single photon emission computed tomography (SPECT) were done to define the pathogenesis of the seizures. The investigations were suggestive of a lack of significant cortical, subcortical, or thalamic structures with hypoplasia of the vermis and cerebellum. SPECT showed little activity in the base of the brain and cerebellum. The cause of the seizures remained unclear in spite of the investigations.