Evaluation of the Patients with the Diagnosis of Pontocerebellar Hypoplasia: A Multicenter National Study

Pontocerebellar hypoplasia (PCH) is a heterogeneous group of neurodegenerative disorders characterized by hypoplasia and degeneration of the cerebellum and pons. We aimed to identify the clinical, laboratory, and imaging findings of the patients with diagnosed PCH with confirmed genetic analysis. We collected available clinical data, laboratory, and imaging findings in our retrospective multicenter national study of 64 patients with PCH in Turkey. The genetic analysis included the whole-exome sequencing (WES), targeted next-generation sequencing (NGS), or single gene analysis. Sixty-four patients with PCH were 28 female (43.8%) and 36 (56.3%) male. The patients revealed homozygous mutation in 89.1%, consanguinity in 79.7%, pregnancy at term in 85.2%, microcephaly in 91.3%, psychomotor retardation in 98.4%, abnormal neurological findings in 100%, seizure in 63.8%, normal biochemistry and metabolic investigations in 92.2%, and dysmorphic findings in 51.2%. The missense mutation was found to be the most common variant type in all patients with PCH. It was detected as CLP1 (n = 17) was the most common PCH related gene. The homozygous missense variant c.419G > A (p.Arg140His) was identified in all patients with CLP1. Moreover, all patients showed the same homozygous missense variant c.919G > T (p.A307S) in TSEN54 group (n = 6). In Turkey, CLP1 was identified as the most common causative gene with the identical variant c.419G > A; p.Arg140His. The current study supports that genotype data on PCH leads to phenotypic variability over a wide phenotypic spectrum.

Dual task impact on functional mobility and interaction of functional level and balance in patients with Duchenne muscular dystrophy

BACKGROUND

Dystrophin, a protein crucial for various brain regions governing higher-order functions like learning and memory is notably absent in individuals with Duchenne muscular dystrophy (DMD). This absence of dystrophin in the brain is believed to underlie cognitive challenges in DMD. Cognitive and motor challenges observed in DMD could potentially hinder the execution of dual tasks.

RESEARCH QUESTION

Is there a significant correlation between dual-task performance, functional mobility, and balance in children with DMD?

METHOD

The study included 28 participants (14 DMD, 14 typical development). Timed Up and Go (TUG) test results were recorded for single and dual-task conditions (motor-motor, cognitive-motor). Functional level was assessed using Motor Function Measurement-32 (MFM-32), Brooke Upper Extremity Scale, and Vignos Scale. Balance was evaluated using Balance Master System and Pediatric Functional Reach Test (PFRT).

RESULTS

Significant differences in TUG test scores across conditions were observed in both DMD and typical development groups (p < 0.05). Children with DMD exhibited longer completion times compared to typical development children (p < 0.05). Among children with DMD, there was a significant correlation between TUG scores in different task conditions and balance assessment (p < 0.05, r = 0.571 to -0.819). Lower MFM-32 scores in DMD children were correlated with worse TUG performance across conditions (p < 0.05, r = 0.586 to -0.868).

SIGNIFIANCE

This study sheds light on the multifaceted nature of dual-tasking challenges in individuals with DMD, thereby contributing to a deeper understanding of the implications for rehabilitation strategies.

The COVID-19 pandemic restrictions affect the healthcare and health status of paediatric patients with neuromuscular diseases: a developing country perspective

PURPOSE

The COVID-19 pandemic has forced the rapid and unprecedented reorganisation of current practices in the treatment of neuromuscular disorders (NMD). Cessation of care and treatments can worsen the underlying condition, exacerbate symptoms, and increase anxiety, leading to a vicious circle and increased management concerns. This study aims to determine the changes in healthcare and health status of children with NMD from a developing country perspective.

MATERIALS AND METHODS

Forty-seven children with NMD were included in this cross-sectional study. The participants were contacted via phone call. The survey conducted for the study was included demographic data, changes and problems in healthcare, perceived health status change, and satisfaction with the services provided. Descriptive statistics were used to characterise the sample.

RESULTS

The mean age of the children was 7.86 ± 3.45 years. The participants encountered 24.83 ± 26.54% of difficulties in getting medication care, and there was 69.95 ± 24.47% disruption in accessing routine medical care. The participants' rehabilitation sessions were disrupted in the 78.54 ± 14.93%, and there were 95.83 ± 10.03% deficiencies in therapists' informing. Children with NMD indicated that their perceived health status decreased compared to before pandemic in all parameters.

CONCLUSION

This study highlights the unfavourable indirect effect of the COVID-19 pandemic restrictions on healthcare and health status of paediatric patients with NMD. Since the COVID-19 pandemic is an uncertain process, the solutions or modifications should be promptly put into effect to improve the healthcare and health status of children with NMD.

High diagnostic rate of trio exome sequencing in consanguineous families with neurogenetic diseases

Consanguineous marriages have a prevalence rate of 24% in Turkey. These carry an increased risk of autosomal recessive genetic conditions, leading to severe disability or premature death, with a significant health and economic burden. A definitive molecular diagnosis could not be achieved in these children previously, as infrastructures and access to sophisticated diagnostic options were limited. We studied the cause of neurogenetic disease in 246 children from 190 consanguineous families recruited in three Turkish hospitals between 2016 and 2020. All patients underwent deep phenotyping and trio whole exome sequencing, and data were integrated in advanced international bioinformatics platforms. We detected causative variants in 119 known disease genes in 72% of families. Due to overlapping phenotypes 52% of the confirmed genetic diagnoses would have been missed on targeted diagnostic gene panels. Likely pathogenic variants in 27 novel genes in 14% of the families increased the diagnostic yield to 86%. Eighty-two per cent of causative variants (141/172) were homozygous, 11 of which were detected in genes previously only associated with autosomal dominant inheritance. Eight families carried two pathogenic variants in different disease genes. De novo (9.3%), X-linked recessive (5.2%) and compound heterozygous (3.5%) variants were less frequent compared to non-consanguineous populations. This cohort provided a unique opportunity to better understand the genetic characteristics of neurogenetic diseases in a consanguineous population. Contrary to what may be expected, causative variants were often not on the longest run of homozygosity and the diagnostic yield was lower in families with the highest degree of consanguinity, due to the high number of homozygous variants in these patients. Pathway analysis highlighted that protein synthesis/degradation defects and metabolic diseases are the most common pathways underlying paediatric neurogenetic disease. In our cohort 164 families (86%) received a diagnosis, enabling prevention of transmission and targeted treatments in 24 patients (10%). We generated an important body of genomic data with lasting impacts on the health and wellbeing of consanguineous families and economic benefit for the healthcare system in Turkey and elsewhere. We demonstrate that an untargeted next generation sequencing approach is far superior to a more targeted gene panel approach, and can be performed without specialized bioinformatics knowledge by clinicians using established pipelines in populations with high rates of consanguinity.

Clinical and genetic characterization of PYROXD1-related myopathy patients from Turkey

Congenital myopathies (CMs) are a heterogeneous group of inherited muscle disorders characterized by muscle weakness at birth, while limb-girdle muscular dystrophies (LGMD) have a later onset and slower disease progression. Thus, detailed clinical phenotyping of genetically defined disease entities are required for the full understanding of genotype-phenotype correlations. A recently defined myopathic genetic disease entity is caused by bi-allelic variants in a gene coding for pyridine nucleotide-disulfide oxidoreductase domain 1 (PYROXD1) with unknown substrates. Here, we present three patients from two consanguineous Turkish families with mild LGMD, facial weakness, normal CK levels, and slow progress. Genomic analyses revealed a homozygous known pathogenic missense variant (c.464A>G, p.Asn155Ser) in family 1 with two affected females. In the affected male of family 2, we found this variant in a compound heterozygous state together with a novel frameshift variant (c.329_332delTCTG, p.Leu112Valfs*8), which is the second frameshift variant known so far in PYROXD1. We have been able to define a large homozygous region in family 1 sharing a common haplotype with family 2 in the critical region. Our data suggest that c.464A>G is a Turkish founder mutation. To gain deeper insights, we performed a systematic review of all published PYROXD1-related myopathy cases. Our analysis showed that the c.464A > G variant was found in 87% (20/23) of the patients and that it may cause either a childhood- or adult-onset phenotype, irrespective of its presence in a homozygous or compound heterozygous state. Interestingly, only four patients had elevated CK levels (up to 1000 U/L), and cardiac involvement was found in few compound heterozygous cases.

Confirmation of TACO1 as a Leigh Syndrome Disease Gene in Two Additional Families

Background:

In 2009, we identified TACO1 as a novel mitochondrial disease gene in a single family, however no second family has been described to confirm the role of TACO1 in mitochondrial disease.

Objective:

In this report, we describe two independent consanguineous families carrying pathogenic variants in TACO1, confirming the phenotype.

Methods:

Detailed clinical investigations and whole exome sequencing with haplotype analysis have been performed in several members of the two reported families.

Results:

Clinical phenotype of the patients confirms the originally reported phenotype of a childhood-onset progressive cerebellar and pyramidal syndrome with optic atrophy and learning difficulties. Brain MRI showed periventricular white matter lesions with multiple cystic defects, suggesting leukoencephalopathy in both patients. One patient carried the previously described homozygous TACO1 variant (p.His158ProfsTer8) and haplotype analysis suggested that this variant is a rare founder mutation. The second patient from another family carried a homozygous novel frame shift variant (p.Cys85PhefsTer15).

Conclusions:

The identification of two Turkish families with similar characteristic clinical presentation and an additional homozygous nonsense mutation confirms that TACO1 is a human mitochondrial disease gene. Although most patients with this clinical presentation undergo next generation sequencing analysis, screening for selected founder mutations in the Turkish population based on the precise clinical presentation may reduce time and cost of finding the genetic diagnosis even in the era of massively parallel sequencing.

Genomic variants causing mitochondrial dysfunction are common in hereditary lower motor neuron disease

Hereditary lower motor neuron diseases (LMND) other than 5q-spinal muscular atrophy (5q-SMA) can be classified according to affected muscle groups. Proximal and distal forms of non-5q-SMA represent a clinically and genetically heterogeneous spectrum characterized by significant overlaps with axonal forms of Charcot-Marie-Tooth (CMT) disease. A consensus for the best approach to molecular diagnosis needs to be reached, especially in light of continuous novel gene discovery and falling costs of next-generation sequencing (NGS). We performed exome sequencing (ES) in 41 families presenting with non-5q-SMA or axonal CMT, 25 of which had undergone a previous negative neuromuscular disease (NMD) gene panel analysis. The total diagnostic yield of ES was 41%. Diagnostic success in the cohort with a previous NMD-panel analysis was significantly extended by ES, primarily due to novel gene associated-phenotypes and uncharacteristic phenotypic presentations. We recommend early ES for individuals with hereditary LMND presenting uncharacteristic or significantly overlapping features. As mitochondrial dysfunction was the underlying pathomechanism in 47% of the solved individuals, we highlight the sensitivity of the anterior horn cell and peripheral nerve to mitochondrial imbalance as well as the necessity to screen for mitochondrial disorders in individuals presenting predominant lower motor neuron symptoms.

Autosomal recessive variants in TUBGCP2 alter the γ-tubulin ring complex leading to neurodevelopmental disease

Microtubules help building the cytoskeleton of neurons and other cells. Several components of the gamma-tubulin (γ-tubulin) complex have been previously reported in human neurodevelopmental diseases. We describe two siblings from a consanguineous Turkish family with dysmorphic features, developmental delay, brain malformation, and epilepsy carrying a homozygous mutation (p.Glu311Lys) in TUBGCP2 encoding the γ-tubulin complex 2 (GCP2) protein. This variant is predicted to disrupt the electrostatic interaction of GCP2 with GCP3. In primary fibroblasts carrying the variant, we observed a faint delocalization of γ-tubulin during the cell cycle but normal GCP2 protein levels. Through mass spectrometry, we observed dysregulation of multiple proteins involved in the assembly and organization of the cytoskeleton and the extracellular matrix, controlling cellular adhesion and of proteins crucial for neuronal homeostasis including axon guidance. In summary, our functional and proteomic studies link TUBGCP2 and the γ-tubulin complex to the development of the central nervous system in humans.

Carbamazepine-Induced Nonepileptic Myoclonus in a Child with Autism and Epilepsy

This study deals with a child with different type of seizures several times in week and unresponsive to antiepileptic drugs. Distinguishing between epileptic seizure and motor tic in a patient diagnosed with epilepsy and autism can be challenging. In this study we presented a male child patient on carbamazepine (CBZ) therapy. In the first days of treatment seizure frequency decreased, but after CBZ treatment dosage reached 15 mg/kg/day (at the 25th day of the treatment), the patient presented to the clinic describing several episodes of myoclonus. There were no changes in electroencephalography during the myoclonus. In follow-up, myoclonus was not described after the cessation of CBZ.

De novo DNM1L variant presenting with severe muscular atrophy, dystonia and sensory neuropathy

DNM1L encodes dynamin-related protein 1 (DRP1), a multi-domain GTPase essential for mitochondrial and peroxisomal division. Autosomal dominant and recessive variants in DNM1L cause encephalopathy due to defective mitochondrial and peroxisomal fission 1 (EMPF1), which presents as a complex and clinically heterogeneous neurological disorder of variable severity, often accompanied by seizures. Clinical features are diverse, and no clear phenotype-genotype correlations were drawn to date. DNM1L-related sensory neuropathy has recently been reported as a predominant feature in one case with a de novo variant in the GTPase domain. Herein we present a second case with DNM1L-related sensory neuropathy as the predominant underlying feature without motor neuron involvement, which resulted in severe muscular atrophy and generalized dystonia.

On the differential diagnosis of neuropathy in neurogenetic disorders

Neuropathy might be the presenting or accompanying sign in many neurogenetic and metabolic disorders apart from the classical-peripheral neuropathies or motor-neuron diseases. This causes a diagnostic challenge which is of particular relevance since a number of the underlying diseases could be treated. Thus, we attempt to give a clinical overview on the most common genetic diseases with clinically manifesting neuropathy.

Congenital myasthenic syndrome-associated agrin variants affect clustering of acetylcholine receptors in a domain-specific manner

Congenital myasthenic syndromes (CMS) are caused by mutations in molecules expressed at the neuromuscular junction. We report clinical, structural, ultrastructural, and electrophysiologic features of 4 CMS patients with 6 heteroallelic variants in AGRN, encoding agrin. One was a 7.9-kb deletion involving the N-terminal laminin-binding domain. Another, c.4744G>A - at the last nucleotide of exon 26 - caused skipping of exon 26. Four missense mutations (p.S1180L, p.R1509W, p.G1675S, and p.Y1877D) expressed in conditioned media decreased AChR clusters in C2C12 myotubes. The agrin-enhanced phosphorylation of MuSK was markedly attenuated by p.Y1877D in the LG3 domain and moderately attenuated by p.R1509W in the LG1 domain but not by the other 2 mutations. The p.S1180L mutation in the SEA domain facilitated degradation of secreted agrin. The p.G1675S mutation in the LG2 domain attenuated anchoring of agrin to the sarcolemma by compromising its binding to heparin. Anchoring of agrin with p.R1509W in the LG1 domain was similarly attenuated. Mutations of agrin affect AChR clustering by enhancing agrin degradation or by suppressing MuSK phosphorylation and/or by compromising anchoring of agrin to the sarcolemma of the neuromuscular junction.

Severe neurodevelopmental disease caused by a homozygous TLK2 variant

A distinct neurodevelopmental phenotype characterised mainly by mild motor and language delay and facial dysmorphism, caused by heterozygous de novo or dominant variants in the TLK2 gene has recently been described. All cases reported carried either truncating variants located throughout the gene, or missense changes principally located at the C-terminal end of the protein mostly resulting in haploinsufficiency of TLK2. Through whole exome sequencing, we identified a homozygous missense variant in TLK2 in a patient showing more severe symptoms than those previously described, including cerebellar vermis hypoplasia and West syndrome. Both parents are heterozygous for the variant and clinically unaffected highlighting that recessive variants in TLK2 can also be disease causing and may act through a different pathomechanism.

COL4A1-related autosomal recessive encephalopathy in 2 Turkish children

OBJECTIVE

This study presents the neurologic phenotypes of 2 brothers with a novel homozygous COL4A1 mutation that was identified in a large Turkish consanguineous cohort of neurogenetic diseases.

METHODS

Whole-exome sequencing and bioinformatic analysis of consanguineous families with children affected by early-onset, neurogenetic disorders was performed using the RD-Connect Genome-Phenome Analysis Platform. We also performed clinical, EEG, and neuroimaging analyses in unaffected siblings and parents.

RESULTS

We have identified a homozygous missense mutation in COL4A1 (p.Gly1278Ser, NM_001845.5:c.3832G>T) in 2 siblings affected by small vessel brain disease with periventricular leukoencephalopathy and ocular defects. Presenting symptoms included mild weakness, hemiparetic gait, pyramidal findings, and seizures, whereas their intellectual and behavioral functions were normal. Both parents and 5 of the siblings (3 boys and 2 girls) were heterozygous for the variant. They did not show any clinical or laboratory signs of small vessel disease.

CONCLUSIONS

COL4A1 has previously been associated with dominant small vessel disease of the brain and other organs, manifesting with high penetrance in heterozygous mutation carriers. Our findings provide evidence that COL4A1-related encephalopathy can be inherited in an autosomal recessive manner, which is important for counseling, prognosis, and treatment. Genotype-phenotype correlations remain to be established.

Ultra-Rare Genetic Variation in the Epilepsies: A Whole-Exome Sequencing Study of 17,606 Individuals

Sequencing-based studies have identified novel risk genes associated with severe epilepsies and revealed an excess of rare deleterious variation in less-severe forms of epilepsy. To identify the shared and distinct ultra-rare genetic risk factors for different types of epilepsies, we performed a whole-exome sequencing (WES) analysis of 9,170 epilepsy-affected individuals and 8,436 controls of European ancestry. We focused on three phenotypic groups: severe developmental and epileptic encephalopathies (DEEs), genetic generalized epilepsy (GGE), and non-acquired focal epilepsy (NAFE). We observed that compared to controls, individuals with any type of epilepsy carried an excess of ultra-rare, deleterious variants in constrained genes and in genes previously associated with epilepsy; we saw the strongest enrichment in individuals with DEEs and the least strong in individuals with NAFE. Moreover, we found that inhibitory GABA_A receptor genes were enriched for missense variants across all three classes of epilepsy, whereas no enrichment was seen in excitatory receptor genes. The larger gene groups for the GABAergic pathway or cation channels also showed a significant mutational burden in DEEs and GGE. Although no single gene surpassed exome-wide significance among individuals with GGE or NAFE, highly constrained genes and genes encoding ion channels were among the lead associations; such genes included CACNA1G, EEF1A2, and GABRG2 for GGE and LGI1, TRIM3, and GABRG2 for NAFE. Our study, the largest epilepsy WES study to date, confirms a convergence in the genetics of severe and less-severe epilepsies associated with ultra-rare coding variation, and it highlights a ubiquitous role for GABAergic inhibition in epilepsy etiology.

A novel mutation in the glycine decarboxylase gene in patient with non-ketotic hyperglycinemia

Non-ketotic hyperglycinemia (NKH) is a rare inborn error of metabolism and is caused by a glycine cleavage system deficiency. Eighty-five percent of patients present with the neonatal type of NKH, the infants initially develop lethargy, seizures, and episodes of apnea, and most often death. Between 60-90% of cases are caused by mutations in the glycine decarboxylase (GLDC). We believed that more mutation reports especially for rare disease as NKH help to evaluate the genotype-phenotype relationship in patients with GLDC. In this study, we describe a case of a neonate admitted to intensive care unit with hypotonia, respiratory failure, lethargy, poor feeding. Due to the history of 2 non-ketotic hyperglycinemia diagnosed male siblings, molecular prenatal diagnosis in patient was performed and a novel c.2963G>A (Arg998Gln) homozygous mutation within the GLDC gene has been detected. We aimed to contribute to mutation knowledge pool of GLDC gene with a novel mutation.

Biallelic variant in AGTPBP1 causes infantile lower motor neuron degeneration and cerebellar atrophy

Infantile hereditary lower motor neuron disorders beyond 5q-spinal muscular atrophy (5q-SMA) are usually caused by mutations other than deletions or mutations in SMN1. In addition to motor neuron degeneration, further neurologic or multisystemic pathologies in non-5q-SMAs are not seldom. Some of the non-5q-SMA phenotypes, such as pontocerebellar hypoplasia (PCH1), have been classified later as a different disease group due to distinctive primary pathologies. Likewise, a novel phenotype, childhood-onset neurodegeneration with cerebellar atrophy (CONDCA) has been described recently in individuals with lower motor neuron disorder and cerebellar atrophy due to biallelic loss-of-function variants in AGTPBP1 that encodes cytosolic carboxypeptidase 1 (CCP1). Here we present two individuals with CONDCA in whom a biallelic missense AGTPBP1 variant (NM_001330701.1:c.2396G>T, p.Arg799Leu) was identified by whole exome sequencing. Affected individuals in this report correspond to the severe infantile spectrum of the disease and underline the severe pathogenic effect of this missense variant. This report is the second in the literature that delineates the pathogenic effects of biallelic AGTPBP1 variants presenting the recently described CONDCA disease.

Targeted sequencing with expanded gene profile enables high diagnostic yield in non-5q-spinal muscular atrophies

Spinal muscular atrophies (SMAs) are a heterogeneous group of disorders characterized by muscular atrophy, weakness, and hypotonia due to suspected lower motor neuron degeneration (LMND). In a large cohort of 3,465 individuals suspected with SMA submitted for SMN1 testing to our routine diagnostic laboratory, 48.8% carried a homozygous SMN1 deletion, 2.8% a subtle mutation, and an SMN1 deletion, whereas 48.4% remained undiagnosed. Recently, several other genes implicated in SMA/LMND have been reported. Despite several efforts to establish a diagnostic algorithm for non-5q-SMA (SMA without deletion or point mutations in SMN1 [5q13.2]), data from large-scale studies are not available. We tested the clinical utility of targeted sequencing in non-5q-SMA by developing two different gene panels. We first analyzed 30 individuals with a small panel including 62 genes associated with LMND using IonTorrent-AmpliSeq target enrichment. Then, additional 65 individuals were tested with a broader panel encompassing up to 479 genes implicated in neuromuscular diseases (NMDs) with Agilent-SureSelect target enrichment. The NMD panel provided a higher diagnostic yield (33%) than the restricted LMND panel (13%). Nondiagnosed cases were further subjected to exome or genome sequencing. Our experience supports the use of gene panels covering a broad disease spectrum for diseases that are highly heterogeneous and clinically difficult to differentiate.

Neurodevelopmental Disorders Caused by De Novo Variants in KCNB1 Genotypes and Phenotypes

Importance

Knowing the range of symptoms seen in patients with a missense or loss-of-function variant in KCNB1 and how these symptoms correlate with the type of variant will help clinicians with diagnosis and prognosis when treating new patients.

Objectives

To investigate the clinical spectrum associated with KCNB1 variants and the genotype-phenotype correlations.

Design, Setting, and Participants

This study summarized the clinical and genetic information of patients with a presumed pathogenic variant in KCNB1. Patients were identified in research projects or during clinical testing. Information on patients from previously published articles was collected and authors contacted if feasible. All patients were seen at a clinic at one of the participating institutes because of presumed genetic disorder. They were tested in a clinical setting or included in a research project.

Main Outcomes and Measures

The genetic variant and its inheritance and information on the patient's symptoms and characteristics in a predefined format. All variants were identified with massive parallel sequencing and confirmed with Sanger sequencing in the patient. Absence of the variant in the parents could be confirmed with Sanger sequencing in all families except one.

Results

Of 26 patients (10 female, 15 male, 1 unknown; mean age at inclusion, 9.8 years; age range, 2-32 years) with developmental delay, 20 (77%) carried a missense variant in the ion channel domain of KCNB1, with a concentration of variants in region S5 to S6. Three variants that led to premature stops were located in the C-terminal and 3 in the ion channel domain. Twenty-one of 25 patients (84%) had seizures, with 9 patients (36%) starting with epileptic spasms between 3 and 18 months of age. All patients had developmental delay, with 17 (65%) experiencing severe developmental delay; 14 (82%) with severe delay had behavioral problems. The developmental delay was milder in 4 of 6 patients with stop variants and in a patient with a variant in the S2 transmembrane element rather than the S4 to S6 region.

Conclusions and Relevance

De novo KCNB1 missense variants in the ion channel domain and loss-of-function variants in this domain and the C-terminal likely cause neurodevelopmental disorders with or without seizures. Patients with presumed pathogenic variants in KCNB1 have a variable phenotype. However, the type and position of the variants in the protein are (imperfectly) correlated with the severity of the disorder.

Common and variable clinical, histological, and imaging findings of recessive RYR1-related centronuclear myopathy patients

Mutations in RYR1 give rise to diverse skeletal muscle phenotypes, ranging from classical central core disease to susceptibility to malignant hyperthermia. Next-generation sequencing has recently shown that RYR1 is implicated in a wide variety of additional myopathies, including centronuclear myopathy. In this work, we established an international cohort of 21 patients from 18 families with autosomal recessive RYR1-related centronuclear myopathy, to better define the clinical, imaging, and histological spectrum of this disorder. Early onset of symptoms with hypotonia, motor developmental delay, proximal muscle weakness, and a stable course were common clinical features in the cohort. Ptosis and/or ophthalmoparesis, facial weakness, thoracic deformities, and spinal involvement were also frequent but variable. A common imaging pattern consisted of selective involvement of the vastus lateralis, adductor magnus, and biceps brachii in comparison to adjacent muscles. In addition to a variable prominence of central nuclei, muscle biopsy from 20 patients showed type 1 fiber predominance and a wide range of intermyofibrillary architecture abnormalities. All families harbored compound heterozygous mutations, most commonly a truncating mutation combined with a missense mutation. This work expands the phenotypic characterization of patients with recessive RYR1-related centronuclear myopathy by highlighting common and variable clinical, histological, and imaging findings in these patients.

Increased Wnt and Notch signaling: a clue to the renal disease in Schimke immuno-osseous dysplasia?

Background

Schimke immuno-osseous dysplasia (SIOD) is a multisystemic disorder caused by biallelic mutations in the SWI/SNF-related matrix-associated actin-dependent regulator of chromatin, subfamily A-like 1 (SMARCAL1) gene. Changes in gene expression underlie the arteriosclerosis and T-cell immunodeficiency of SIOD; therefore, we hypothesized that SMARCAL1 deficiency causes the focal segmental glomerulosclerosis (FSGS) of SIOD by altering renal gene expression. We tested this hypothesis by gene expression analysis of an SIOD patient kidney and verified these findings through immunofluorescent analysis in additional SIOD patients and a genetic interaction analysis in Drosophila.

Results

We found increased expression of components and targets of the Wnt and Notch signaling pathways in the SIOD patient kidney, increased levels of unphosphorylated β-catenin and Notch1 intracellular domain in the glomeruli of most SIOD patient kidneys, and genetic interaction between the Drosophila SMARCAL1 homologue Marcal1 and genes of the Wnt and Notch signaling pathways.

Conclusions

We conclude that increased Wnt and Notch activity result from SMARCAL1 deficiency and, as established causes of FSGS, contribute to the renal disease of most SIOD patients. This further clarifies the pathogenesis of SIOD and will hopefully direct potential therapeutic approaches for SIOD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0519-7) contains supplementary material, which is available to authorized users.

A Multinational Survey on Actual Diagnostics and Treatment of Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a chronic infection of the central nervous system caused by the measles virus (MV). Its prevalence remains high in resource poor countries and is likely to increase in the Northern Europe as vaccination rates decrease. Clinical knowledge of this devastating condition, however, is limited. We therefore conducted this multinational survey summarizing experience obtained from more than 500 patients treated by 24 physicians in seven countries. SSPE should be considered in all patients presenting with otherwise unexplained acquired neurological symptoms. In most patients, the diagnosis will be established by the combination of typical clinical symptoms (characteristic repetitive myoclonic jerks), a strong intrathecal synthesis of antibodies to MV and typical electroencephalogram findings (Radermecker complexes). Whereas the therapeutic use of different antiviral (amantadine, ribavirin) and immunomodulatory drugs (isoprinosine, interferons) and of immunoglobulins has been reported repeatedly, optimum application regimen of these drugs has not been established. This is partly due to the absence of common diagnostic and clinical standards focusing on neurological and psychosocial aspects. Carbamazepine, levetiracetam, and clobazam are the drugs most frequently used to control myoclonic jerks. We have established a consensus on essential laboratory and clinical parameters that should facilitate collaborative studies. Those are urgently needed to improve outcome.

The Paediatric migraine disability assessment score is a useful tool for evaluating prophylactic migraine treatment

AIM

There is a need for an objective assessment scoring system to evaluate the effectiveness of prophylactic drugs in paediatric migraine, and the aim of this study was to evaluate the Paediatric Migraine Disability Assessment Score (PedMIDAS).

METHODS

We recruited 88 children aged between 6 and 17 years of age with migraine. The 53 children in the treatment group were divided into three groups according to the prophylactic drug they received topiramate, flunarizine and propranolol and assessed using PedMIDAS before the start of treatment and 3 and 6 months after treatment. The 35 patients in the control group did not receive prophylactic treatment and were assessed with PedMIDAS on three occasions, 3 months apart.

RESULTS

Topiramate, propranolol and flunarizine treatments significantly decreased PedMIDASs and were shown to be effective in improving the patients' quality of life. Topiramate and propranolol were more effective than flunarizine. The number of days on analgesic treatment significantly decreased in the patients who had received topiramate and propranolol treatments (p < 0.05), but remained unchanged in the flunarizine prophylaxis group (p > 0.05).

CONCLUSION

The PedMIDAS scoring system is useful in evaluating the efficacy of prophylactic therapy in paediatric migraine. Topiramate and propranolol lowered the PedMIDASs better than flunarizine.

Effects of hyperglycemia on the developing brain in newborns

BACKGROUND

Hyperglycemia is a common problem in preterm neonates and is associated with increased risk of mortality and severe morbidities such as brain damage. However, available data about the effects of severity of hyperglycemia on the developing brain in the early life is limited. Therefore, we evaluated the effects of moderate and severe hyperglycemia on the developing brain.

METHOD

Thirty newborn Sprague-Dawley rats were randomly divided into three groups as control, moderate hyperglycemia (30% dextrose), and severe hyperglycemia (50% dextrose). Pups in the hyperglycemia groups were administered subcutaneous sterile dextrose solution at a dose of 4 mL/kg daily from the second day to the eleventh day of life. Blood glucose levels were measured every day in all study groups. Rat brain tissues were removed at the end of the study. Histopathologic and immunohistochemical (caspase-9, -8, and -3) examination and biochemical analysis including xanthine oxidase, total antioxidant status, total oxidant status, and malondialdehyde activities were performed.

RESULTS

Weight of the brain tissues in rats with hyperglycemia groups was significantly lower than the control group (P < 0.05). Weight of the brain tissues in rats with moderate hyperglycemia was lower than that of the severe hyperglycemia (P < 0.05). In the histopathologic and immunochemical evaluation, severity of brain damage and apoptosis were significantly higher in the severe hyperglycemia group, especially at the level of the hippocampus (P < 0.05). Tissue malondialdehyde, xanthine oxidase levels, and total oxidant status were significantly increased in the severe hyperglycemia group, whereas total antioxidant status was significantly decreased in the severe hyperglycemia group (P < 0.001).

CONCLUSION

Brain damaging effects of severe hyperglycemia were observed in the developing brains of the rat pups. It might be inferred that severe hyperglycemia can damage the developing brain especially in preterm infants.

Comparison of cranial magnetic resonance imaging findings and clinical features in patients with corpus callosum abnormalities

AIM

The aim of this study was to evaluate the relationship between clinical and cranial magnetic resonance imaging findings in patients with corpus callosum (CC) abnormalities.

PATIENTS AND METHODS

Between September 2010 and March 2012, patients with developmental CC abnormalities were included in the study. CC abnormalities were classified as total agenesis, partial agenesis, and callosal hypoplasia. Regarding the groups, the association between radiological abnormalities and clinical findings were evaluated.

RESULTS

A total of 62 patients (32 females [51.6%] and 30 males [48.4%]) with a mean age of 18.0 ± 32.1 months were enrolled in the study. Of them, 20 patients (32.3%) had total agenesis, 9 patients (14.5%) had partial agenesis, and 33 (53.2%) patients had hypoplasia of the CC. Thirty-five cases (56.7%) had abnormal physical examination, 47 cases (75.8%) had abnormal neurological examination, and 42 cases (67.7%) had psychomotor retardation. There were no significant differences between groups regarding physical examination, psychomotor retardation, seizures, or microcephaly. Seizures, psychomotor retardation, and neurological abnormalities were significantly more frequent in patients with associated other radiological abnormalities. Posterior segment of the CC was significantly thinner in patients with psychomotor retardation and the anterior part of the CC thinner in patients with abnormal physical examination. Patients with total agenesis were more prone to seizures at an early age than patients with partial agenesis or hypoplasia.

CONCLUSION

The neurological prognosis of patients with CC abnormalities is poorer in patients with an associated neuroradiological abnormality. Early development of seizures may be observed in cases with total agenesis of the CC.

Importance of diazepam administration during electroencephalography in the differential diagnosis of cortical visual loss

A 14-year-old boy presented with acute visual loss due to cortical blindness. Two weeks after the visual symptoms, the patient developed behavioral abnormalities. Brain magnetic resonance imaging (MRI) revealed hyperintense lesions at parieto-occipital lobes on T2-weighted and fluid attenuated inversion recovery images. Sleep and awake electroencephalography (EEG) were normal, but diazepam administration revealed bilateral periodic synchronous complexes occurring every 20 to 30 seconds. Elevated measles antibody titers in cerebrospinal fluid confirmed the diagnosis of subacute sclerosing panencephalitis. We conclude that visual loss due to cortical blindness is an important finding of subacute sclerosing panencephalitis. Diazepam administration during EEG should be a part of investigation in cases with unexplained cortical blindness.

The combination of thermal dysregulation and agenesis of corpus callosum: Shapiro's or/and reverse Shapiro's syndrome

Shapiro syndrome is an extremely rare condition consisting the clinical triad of recurrent hypothermia, hyperhydrosis and agenesis of the corpus callosum. On the other hand, reverse Shapiro's sydrome is characterized periodic hyperthermia and agenesis of the corpus callosum. Here, we describe a 3.5-year-old girl with complete agenesis of corpus callosum presenting with recurrent fever and vomiting. She also had hypothermia attacks with accompanying diaphoresis. To the best of our knowledge, there is no described case with episodes of hyperthermia, hypothermia, and vomiting associated with agenesis of the corpus callosum. Recurrent vomiting may be a newly defined symptom associated with these syndromes.

Coexistence of myositis, transverse myelitis, and Guillain Barré syndrome following Mycoplasma pneumoniae infection in an adolescent

Guillain-Barré syndrome (GBS) and transverse myelitis may occur coexistently in the pediatric population. This may be explained by a shared epitope between peripheral and central nervous system myelin. Coexistent transverse myelitis, myositis, and acute motor neuropathy in childhood have not been previously described. We describe a 14-year-old female patient with transverse myelitis, myositis, and GBS following Mycoplasma pneumoniae infection. She presented with weakness and walking disability. Weakness progressed to involve all extremities and ultimately, she was unable to stand and sit. Based on the clinical findings, a presumptive diagnosis of myositis was made at an outside institution because of high serum creatine kinase level. The patient was referred to our institution for further investigation. Magnetic resonance imaging of spine revealed enhancing hyperintense lesions in the anterior cervicothoracic spinal cord. The electromyography revealed acute motor polyneuropathy. Serum M. pneumoniae IgM and IgG were positive indicating an acute infection. Repeated M. pneumoniae serology showed a significant increase in Mycoplasma IgG titer. The patient was given intravenous immunoglobulin for 2 days and clarithromycin for 2 weeks. She was able to walk without support after 2 weeks of hospitalization. This paper emphasizes the rarity of concomitant myositis, transverse myelitis, and GBS in children.

Correlation between motor performance scales, body composition, and anthropometry in patients with Duchenne muscular dystrophy

The aim of this study is to investigate the relationship between body composition, anthropometry, and motor scales in patients with Duchenne muscular dystrophy (DMD). Twenty six patients with DMD were evaluated by Expanded Hammersmith Functional Motor Scale (HFMSE), gross motor function classification system (GMFCS), multifrequency bioelectrical impedance analysis, and anthropometric measurements. Seventeen healthy children served as control group. There were 26 patients with a mean age of 9.5 ± 4.8 years. Ages and anthropometric measurements did not differ between groups. Of the 26 patients, nine were level I, seven were level II, two were level III, seven were level IV, and one was level V, according to the GMFCS. Despite the similar percentage of total body water, extracellular water/intracellular water ratio was significantly elevated in DMD patients (p = 0.001). Increased values of fat percentage and body fat mass index (BFMI) correlated positively with elevated GMFCS levels (r = 0.785 and 0.719 respectively). Increased fat-free mass index (FFMI) correlated negatively with elevated GMFCS levels (r = -0.401). Increased fat percentage and BFMI correlated negatively with HFMSE scores (r = -0.779 and -0.698, respectively). Increased values of FFMI correlated positively with HFMSE scores. There was also a negative correlation between increased skin fold measurements from triceps and scapula and HFMSE scores (r = -0.618 and -0.683, respectively). Increased skin fold values from the same regions correlated positively with elevated GMFCS levels (r = 0.643 and 0.712, respectively). Significant body composition changes occur in patients with DMD. Anthropometric and multifrequency bioelectrical impedance analyses measurements show good correlation between motor function scales. These results may also be helpful to evaluate the effects of new treatment strategies.

Incidental white matter lesions in children presentıng with headache

AIM

We aimed to describe the prevalence and significance of white matter lesions detected on magnetic resonance imaging (MRI) in children with headache.

MATERIAL AND METHODS

Children who were admitted with the complaint of headache and had neuroimaging between December 2007 and June 2012 were included in the study. The clinical and neuroimaging data of the patients were retrospectively evaluated. MRI results of the patients were documented in detail. The patients with non-specific white matter lesions were called for a control visit, and current status of headache and neurological findings were determined.

RESULTS

A total of 941 patients were included in the study. Sixty-one percent of the patients received cranial neuroimaging. 8.2% had only cranial computed tomography (CT), 7.5% had cranial CT and cranial MRI, and 84.3% had only cranial MRI. 22.1% of the patients had abnormal cranial MRI findings. The rate of incidental non-specific white matter changes detected in our study group was 23/527 (4.4%). Among the 23 patients, 12 (52.2%) were male and 11 (47.8%) were female. Fourteen (60.9%) had migraine without aura, 8 (34.8%) had tension-type headache, and 1 (4.3%) had migraine with aura. Mean age of patients at the time of imaging was 12.1 ± 3.4 years (range 4.0-16.0 years). All patients with non-specific white matter changes on MRI showed normal psychomotor development, and there was no history of seizures or head trauma. The physical and neurological examinations of all patients were normal. The mean clinical follow-up period of the patients was 16.8 ± 17.3 months (range 6-80 months). No patients showed neurological deterioration during the follow up. The white matter lesions were supratentorial in all patients. The mean size of the lesions was 5.1 ± 4.5 mm (minimum, 2 mm; maximum, 24 mm). Repeated radiological evaluations were performed in 11 (47.8%) of the patients. No new white matter lesions were detected in control MRI during follow up.

CONCLUSION

Non-specific incidental white matter changes may be seen in children with headache. For normal clinical follow up, in the absence of evident benefits from repeated imaging studies, we suggest that repeated imaging studies are not warranted in every patient and should be tailored according to clinical course.

Molybdenum cofactor deficiency: review of 12 cases (MoCD and review)

Molybdenum cofactor deficiency is a rare inborn error of metabolism. The major clinical symptoms are intractable neonatal seizures, progressive encephalopathy, facial dysmorphic features and feeding difficulties. Most of the patients are misdiagnosed as hypoxic ischemic encephalopathy. The majority of patients have mutations in the MOCS1 and MOCS2 genes. Although the therapeutic treatment strategies have not been improved, genetic analysis is essential to elucidate the disease. Here, we report a review of 12 patients with Molybdenum cofactor deficiency reported from Turkey.

Defects in amphiphysin 2 (BIN1) and triads in several forms of centronuclear myopathies

Myotubular myopathy and centronuclear myopathies (CNM) are congenital myopathies characterized by generalized muscle weakness and mislocalization of muscle fiber nuclei. Genetically distinct forms exist, and mutations in BIN1 were recently identified in autosomal recessive cases (ARCNM). Amphiphysins have been implicated in membrane remodeling in brain and skeletal muscle. Our objective was to decipher the pathogenetic mechanisms underlying different forms of CNM, with a focus on ARCNM cases. In this study, we compare the histopathological features from patients with X-linked, autosomal recessive, and dominant forms, respectively, mutated in myotubularin (MTM1), amphiphysin 2 (BIN1), and dynamin 2 (DNM2). We further characterize the ultrastructural defects in ARCNM muscles. We demonstrate that the two BIN1 isoforms expressed in skeletal muscle possess the phosphoinositide-binding domain and are specifically targeted to the triads close to the DHPR-RYR1 complex. Cardiac isoforms do not contain this domain, suggesting that splicing of BIN1 regulates its specific function in skeletal muscle. Immunofluorescence analyses of muscles from patients with BIN1 mutations reveal aberrations of BIN1 localization and triad organization. These defects are also observed in X-linked and autosomal dominant forms of CNM and in Mtm1 knockout mice. In addition to previously reported implications of BIN1 in cancer as a tumor suppressor, these findings sustain an important role for BIN1 skeletal muscle isoforms in membrane remodeling and organization of the excitation-contraction machinery. We propose that aberrant BIN1 localization and defects in triad structure are part of a common pathogenetic mechanism shared between the three forms of centronuclear myopathies.

Fukutin mutations in non-Japanese patients with congenital muscular dystrophy: less severe mutations predominate in patients with a non-Walker-Warburg phenotype

Six genes including POMT1, POMT2, POMGNT1, FKRP, Fukutin (FKTN) and LARGE encode proteins involved in the glycosylation of α-dystroglycan (α-DG). Abnormal glycosylation of α-DG is a common finding in Walker-Warburg syndrome (WWS), muscle-eye-brain disease (MEB), Fukuyama congenital muscular dystrophy (FCMD), congenital muscular dystrophy types 1C and 1D and some forms of autosomal recessive limb-girdle muscular dystrophy (LGMD2I, LGMD2K, LGMD2M), and is associated with mutations in the above genes. FCMD, caused by mutations in Fukutin (FKTN), is most frequent in Japan, but an increasing number of FKTN mutations are being reported outside of Japan. We describe four new patients with FKTN mutations and phenotypes ranging from: severe WWS in a Greek-Croatian patient, to congenital muscular dystrophy and cobblestone lissencephaly resembling MEB-FCMD in two Turkish patients, and limb-girdle muscular dystrophy and no mental retardation in a German patient. Four of the five different FKTN mutations have not been previously described.

The relationship of neonatal subclinical electrographic seizures to neurodevelopmental outcome at 1 year of age

OBJECTIVE

To evaluate the influence of 'only electroencephalographic (EEG)' and 'EEG plus clinical' seizures during neonatal period on neurodevelopment of the infants.

PATIENTS AND METHODS

The long-term digital-video- EEG tracings of the first 3 days of life of 30 neonates were assessed. The babies were subdivided into three groups: Group 1 had neither EEG nor clinical seizures. Group 2 had EEG seizures but no clinical seizures. Group 3 experienced both EEG and clinical seizures. The groups were compared in regard to psychomotor retardation and epilepsy at corrected age of 1 year.

RESULTS

The mean birthweight was 1952.50 +/- 978.74 (685-4103) g. The mean gestational age was 32.53 +/- 4.26 (24-40) weeks. In regard to sex, gestational age and birth weight, there was no significant difference between the three groups. Ten percent of newborns in Group 1 and 53.8% of newborns in Group 3 had psychomotor retardation. No babies in Group 2 experienced psychomotor retardation. The differences between the Groups 1 and 3 and Groups 2 and 3 were found statistically significant. Only one baby in Group 3 had epilepsy. In Groups 1 and 2, no babies had epilepsy. The differences between the groups were not significant.

CONCLUSION

Neonatal seizures, but not silent EEG seizures are in relationship with poor neurodevelopmental outcome evaluated at corrected age of 1 year in newborns.

Metabolic alterations during valproic acid treatment: a prospective study

We prospectively examined the effects of valproic acid on the endocrine system and metabolic variables in epileptic children. Patients with newly diagnosed idiopathic epilepsy were included in the study. Laboratory and clinical variables were assessed before and after 6 and 12 months of treatment. In total, 30 patients (mean age, 8.6 +/- 4.4 years S.D.) were investigated. Body mass index and body mass index standard deviation scores of patients increased significantly during treatment. Although there was no statistical significance regarding fasting glucose, serum insulin, triglyceride, and high-density lipoprotein cholesterol levels and the insulin resistance index, a statistically significant increase in total and low-density lipoprotein cholesterol levels had occurred after 12 months of valproic acid treatment. At the end of the study period, four patients were obese, and six patients were overweight. There was a significant correlation between serum levels of valproic acid and body mass index at month 6 of treatment. There was no significant change in androgen hormone levels during treatment in the prepubertal group. Body mass index and body mass index standard deviation scores increased during the first 6 months of valproic acid treatment. Patients treated with valproic acid should be regularly followed for obesity.

Clinical, pathological and radiological survey of patients with Leigh syndrome

AIM

The aim of this study was to evaluate the clinical, pathological and radiological survey of patients affected by Leigh syndrome.

METHODS

Eleven patients with Leigh disease were evaluated at Dokuz Eylül University, School of Medicine, Department of Pediatric Neurology. All patients underwent neurological evaluation with detailed medical and family history. Muscle biopsy from quadriceps muscle, brain magnetic resonance imaging and brain magnetic spectroscopy were obtained.

RESULTS

The patients were aged between 1 month and 8 years (mean age: 2.29+/-2.58 years). The most common presentation findings were psychomotor retardation and acute metabolic encephalopathy. All patients had elevated lactate in the blood and/or cerebrospinal fluid. Except in two patients, brain magnetic resonance imaging revealed abnormal symmetrical lesions in the brainstem and basal ganglia. Brain magnetic resonance spectroscopy revealed abnormal lactate peak in all patients. The muscle biopsy of two patients showed cytocrom-c oxidase deficiency and measurement of respiratory chain complex in one patient revealed complex I and IV deficiency. One patient was found to carry mitochondrial T8993C mutation.

CONCLUSIONS

There are no specific markers for Leigh disease which lead to extensive work-up. The disease should be considered in patients who present progressive neurologic symptoms involving brainstem and basal ganglia.

Diagnostic value of proton MR spectroscopy and diffusion-weighted MR imaging in childhood inherited neurometabolic brain diseases and review of the literature

The purpose of this study is to evaluate parenchymal diffusion properties and metabolite ratios in affected brain tissues of inherited neurometabolic brain diseases with an overview of the current literature about the diagnostic data of both techniques in childhood inherited metabolic brain diseases. The study group was consisting, 19 patients (15 males, 4 females; mean age, 54 months (4.5 years); age range, 1-171 months (14.25 years)) diagnosed with inherited neurometabolic brain disease. Single- and multivoxel proton MRS was carried out and NAA/Cr, Cho/Cr, mI/Cr, Glx/Cr ratios were calculated. Presence of lactate peak and abnormal different peaks were noted. ADC values were calculated from brain lesions. Results are compared with age and sex matched normal subjects. Elevated NAA/Cr ratio (Canavan disease), galactitol peak (galactosemia) at 3.7 ppm, branched chain amino acids (Maple syrup urine disease-MSUD) at 0.9 ppm were seen on different diseases. In Leigh disease and MSUD restricted diffusion was detected. Different diffusion properties were seen only in one Glutaric aciduria lesions. NAA/Cr ratios and calculated ADC values were significantly different from normal subjects (p<0.05). DWI combined with MRS are complementary methods to routine cranial MRI for evaluating neurometabolic diseases which can give detailed information about neurochemistry of affected brain areas.