Epidemiology of type 1 diabetes mellitus in children and adolescents: A 50-year, single-center experience.

BACKGROUND: Global variations in epidemiology of type 1 diabetes mellitus (T1DM) exist. This study is designed to examine demographic and clinical features of T1DM over the past 3 decades as well as evolving trends in epidemiology over last 50 years. METHODS: Clinical characteristics of 925 patients with T1DM over last 30 years (1990-2019) were evaluated and compared to previously published data of 477 patients diagnosed between 1969 and 1990 from one of the major referral centers for diabetes in Turkey. RESULTS: Mean age at diagnosis decreased from 9.5 ± 4.0 to 7.1 ± 3.6 years within the past 50 years (p < .001). Age at diagnosis peaked at 12-14 years between 1969 and 1990, then fell to 10-11.9 years between 1990 and 1999, and to 4-5.9 years between 2000-2009 and 2010-2019 (p = .005). Although the percentage of patients diagnosed <6 years of age is gradually increasing, the percentage between the ages of 6 and 11.9 years is decreasing, and the percentage diagnosed ≥12 years remained stable. A total of 47.5% of patients had ketoacidosis, 38.2% had ketosis, and 14.3% had only hyperglycemia. 23% of patients had severe diabetic ketoacidosis (DKA), whereas 42% had moderate. Over last 3 decades, there has been no change in frequency of ketoacidosis at presentation, but there has been significant decline in severity (p = .865, and p < .001, respectively). Although the frequency of patients with mild DKA increased over time, frequency of patients with moderate DKA decreased; however, no significant difference was observed among patients with severe ketoacidosis. DKA was more frequent and severe in patients <6 years of age (p = .005, and p < .001, respectively). CONCLUSION: Age at diagnosis shifted to younger ages in T1DM in the past 50 years. Half of patients had ketoacidosis at diagnosis and frequency of presentation with DKA did not decrease, but severity decreased slightly. Increase in prevalence of T1DM in the younger age group and the fact that half of patients present with DKA indicate that awareness should be increased in terms of early diagnosis and treatment.

Electro-clinical features and long-term outcomes in guanidinoacetate methyltransferase (GAMT) deficiency.

OBJECTIVE: To evaluate clinical characteristics and long-term outcomes in patients with guanidinoacetate methyltransferase (GAMT) deficiency with a special emphasis on seizures and electroencephalography (EEG) findings. METHODS: We retrospectively analyzed the clinical and molecular characteristics, seizure types, EEG findings, neuroimaging features, clinical severity scores, and treatment outcomes in six patients diagnosed with GAMT deficiency. RESULTS: Median age at presentation and diagnosis were 11.5 months (8-12 months) and 63 months (18 months -11 years), respectively. Median duration of follow-up was 14 years. Global developmental delay (6/6) and seizures (5/6) were the most common symptoms. Four patients presented with febrile seizures. The age at seizure-onset ranged between 8 months and 4 years. Most common seizure types were generalized tonic seizures (n = 4) and motor seizures resulting in drop attacks (n = 3). Slow background activity (n = 5) and generalized irregular sharp and slow waves (n = 3) were the most common EEG findings. Burst-suppression and electrical status epilepticus during slow-wave sleep (ESES) pattern was present in one patient. Three of six patients had drug-resistant epilepsy. Post-treatment clinical severity scores showed improvement regarding movement disorders and epilepsy. All patients were seizure-free in the follow-up. CONCLUSIONS: Epilepsy is one of the main symptoms in GAMT deficiency with various seizure types and non-specific EEG findings. Early diagnosis and initiation of treatment are crucial for better seizure and cognitive outcomes. This long-term follow up study highlights to include cerebral creatine deficiency syndromes in the differential diagnosis of patients with global developmental delay and epilepsy and describes the course under treatment.

High diagnostic yield of targeted next-generation sequencing panel as a first-tier molecular test for the patients with myopathy or muscular dystrophy.

Muscular dystrophies are a heterogeneous group of neuromuscular disorders with a wide range of the clinical and genetic spectrum. Whole-exome sequencing (WES) has been on the rise to become the usual method of choice for molecular diagnosis in patients presenting with muscular dystrophy or congenital or metabolic myopathy phenotype. Here, we used a panel with 47 genes including not only muscular dystrophy but also myopathy-associated genes that had been used as a first-tier approach. A total of 146 patients who were referred to our clinic with the prediagnosis of muscular dystrophy and/or myopathy were included in the study. Dystrophin gene deletion/duplication was ruled out on the patients with a preliminary diagnosis of Duchenne muscular dystrophy. In this study, the molecular etiology of 67 patients was proved with the gene panel with a diagnostic yield of 46%. Causal variants were identified in 23 genes including CAPN3(11), DYSF(9), DMD(8), SGCA(5), TTN(4), LAMA2(3), LMNA(3), SGCB(3), COL6A1(3), DES (2), CAV3(2), FKRP(2), FKTN(2), ANO5, COL6A2, CLCN1, GNE, POMGNT1, POMGNT2, POMT2, SYNE1, TCAP, and FLNC with 16 novel variants. There were 27 patients with uncertain molecular results including the ones who had a variant of uncertain significance, who had only one heterozygous variant for an autosomal recessive disease, and the ones who had two variants in different genes. Molecular diagnosis in muscular dystrophy is essential to plan clinical management and choosing treatment options. Also, the results will affect the reproduction options. Targeted next-generation sequencing is a cost-effective method that reduces the WES requirements with a significant diagnostic rate.

FXR1-related congenital myopathy: expansion of the clinical and genetic spectrum.

BACKGROUND: Biallelic pathogenic variants in FXR1 have recently been associated with two congenital myopathy phenotypes: a severe form associated with hypotonia, long bone fractures, respiratory insufficiency and infantile death, and a milder form characterised by proximal muscle weakness with survival into adulthood. OBJECTIVE: We report eight patients from four unrelated families with biallelic pathogenic variants in exon 15 of FXR1. METHODS: Whole exome sequencing was used to detect variants in FXR1. RESULTS: Common clinical features were noted for all patients, which included proximal myopathy, normal serum creatine kinase levels and diffuse muscle atrophy with relative preservation of the quadriceps femoris muscle on muscle imaging. Additionally, some patients with FXR1-related myopathy had respiratory involvement and required bilevel positive airway pressure support. Muscle biopsy showed multi-minicores and type I fibre predominance with internalised nuclei. CONCLUSION: FXR1-related congenital myopathy is an emerging entity that is clinically recognisable. Phenotypic variability associated with variants in FXR1 can result from differences in variant location and type and is also observed between patients homozygous for the same variant, rendering specific genotype-phenotype correlations difficult. Our work broadens the phenotypic spectrum of FXR1-related congenital myopathy.

Clinical and laboratory features of children with tremor: a single-center experience.

AIM: Tremor is an involuntary, rhythmic, oscillatory movement of body parts around a central point or plane which arises from contraction of antagonist muscles. Evaluation of pediatric patients with tremor can be challenging due to limited population-based studies in children. The aim of this study is to evaluate the demographic, clinical and laboratory features of childhood tremor, retrospectively. MATERIALS AND METHODS: Patients under the age of 18 years presenting with tremor (n = 111) to the Pediatric Neurology Unit of Kecioren Research and Training Hospital between January 2014 and December 2019 were included in the study. Patients with neuromuscular disease, vertebral pathology or incomplete data in hospital records were not included. Also, benign tremor causes (jitteriness, shuddering attack, etc.) seen in the neonatal and infancy period were excluded from the study as the number of patients was insufficient. Demographic data, type and duration of tremor, accompanying symptoms, chronic diseases and medications, family history, physical and neurological examination, laboratory findings, neuroimaging findings were retrospectively analyzed and recorded. RESULTS: A total of 111 children (59 girls and 52 boys) were included in our study and the female to male ratio was 1.1. The mean age at tremor onset and age at admission to hospital were 13.2 ± 2.8 years (range 4-17 years), and 14.8 ± 2.0 years (range 6-17 years), respectively. The most common type of tremor was essential tremor (62.2%), followed by enhanced physiologic (18.9%). None of the patients had acute metabolic disorder. Diagnostic tests revealed the etiology in 12 patients. These were vitamin B12 deficiency in 11 patients and multiple sclerosis in one patient. Drug-induced and task-specific tremors were determined in 4 patients each. It was determined that in patients with a positive family history, tremor appeared or was noticed at a younger age. CONCLUSIONS: Most of the cases with tremor can be diagnosed accurately by a detailed medical history, physical and neurological examination. Essential tremor is the most common type of tremor in children. Laboratory tests and imaging methods have limited additional yield in elucidating the etiology. Early recognition of tremor and related signs and symptoms in childhood is important for the detection and treatment of the possible underlying cause.

Unraveling neuronal ceroid lipofuscinosis type 2 (CLN2) disease: A tertiary center experience for determinants of diagnostic delay.

OBJECTIVE: To evaluate the clinical phenotype, disease course, laboratory, and genetic features of patients with CLN2 disease over a 20 year period with a special emphasis on risk factors for diagnostic delay. METHODS: Thirty patients (23 families) with CLN2 disease, evaluated between 1996 and 2019 in a tertiary referral center in Turkey, were included. Clinical features, diagnostic pathway, disease course, genetic data, electrophysiological, and neuroimaging findings were analyzed, retrospectively. The patients diagnosed between 1996 and 2009, and 2010-2019 were defined as group 1 (G1), and group 2 (G2), respectively. Patients in these two groups were also compared. RESULTS: The median age at symptom-onset was 36 months (20 months-7 years). Most common presenting symptoms were seizures (70%), followed by language delay (43%), and psychomotor regression (27%). Median age at diagnosis was 5.2 years (1.6-11 years) with a median 27 months (1 month-7 years) of diagnostic delay. Age at diagnosis was earlier in G2 (4.6 years vs 7 years, p = 0.002), with a shorter time to diagnosis (21 months vs 39 months, p = 0.004). Median time between the onset of first symptoms and death was 8.3 years (SE 1.0). Electroencephalograms (EEG) revealed abnormal features predominantly in posterior hemispheral regions and a photoparoxysmal response to intermittent photic stimulation was detected in 53% of the patients. Cerebellar (96%)/cerebral atrophy (83%), and white matter changes (57%) were the most common radiological abnormalities. CONCLUSIONS: Most of our patients presented with late-infantile onset seizures. Despite increased availability of enzymatic and molecular testing, there is still a considerable diagnostic delay.

Selenoprotein N-related myopathy: a retrospective natural history study to guide clinical trials.

OBJECTIVE: To describe clinical features and disease progression of Selenoprotein N-related myopathy in a large multicenter cohort of patients. METHODS: Cross-sectional multicenter data analysis of 60 patients (53 families) with Selenoprotein N-related myopathy and single-center retrospective longitudinal analysis of 25 patients (21 families) over a median period of 5.3 years. RESULTS: The majority of patients (46/60, 77%) presented before age 2 years with hypotonia, poor head/neck control, and developmental delay. At last assessment (median age 14 years; range 2.5 to 36 years), 10/60 patients had minimal or no ambulation. Ventilatory support was initiated in 50/60 patients at a mean Forced Vital Capacity (FVC) of 38% and at a median age of 13 years. Forty-five/60 patients developed scoliosis (at median age 12.1 years) and 18 had scoliosis surgery at a median age of 13.6 years. Five children needed nasogastric feeds and/or gastrostomy. Longitudinal data analysis on 25 patients showed progressive decline of Hammersmith functional motor scores (estimated annual change -0.55 point), time to walk 10 meter, time standing from sitting, and from lying. Sixteen patients had weights < 2nd centile. The estimated change in FVC % per year was -2.04, with a 95% CI (-2.94, -1.14). CONCLUSIONS: This comprehensive analysis of patients with Selenoprotein N-related myopathy further describes the clinical course of this rare condition. The observed functional motor and respiratory data provide evidence of the slow decline patients experience over time which is useful when considering therapeutic intervention.

Long-term effects of vagus nerve stimulation in refractory pediatric epilepsy: A single-center experience.

INTRODUCTION: Vagus nerve stimulation (VNS) has been used as an adjunctive therapy for both children and adults with refractory epilepsy, over the last two decades. In this study, we aimed to evaluate the long-term effects and tolerability of VNS in the pediatric drug-resistant epilepsy (DRE) and to identify the predictive factors for responsiveness to VNS. METHODS: We retrospectively reviewed the medical records of pediatric patients who underwent VNS implantation between 1997 and 2018. Patients with ≥50% reduction of seizure frequency compared with the baseline were defined as "responders". The clinical characteristics of responders and nonresponders were compared. RESULTS: A total of 58 children (male/female: 40/18) with a mean follow-up duration of 5.7 years (3 months to 20 years) were included. The mean age at implantation was 12.4 years (4.5 to 18.5 years). Approximately half (45%) of our patients were responders, including 3 patients (5.8%) who achieved seizure freedom during follow-up. The age of seizure-onset, duration of epilepsy, age at implantation, and etiologies of epilepsy showed no significant difference between responders and nonresponders. Responders were more likely to have focal or multifocal epileptiform discharges (63%) on interictal electroencephalogram (EEG), when compared to nonresponders (36%) (p = .07). Vocal disturbances and paresthesias were the most common side effects, and in two patients, VNS was removed because of local reaction. CONCLUSION: Our series had a diverse etiological profile and patients with transition to adult care. Long-term follow-up showed that VNS is an effective and well-tolerated treatment modality for refractory childhood onset epilepsy. Age at implantation, duration of epilepsy and underlying etiology are not found to be predictors of responsiveness to VNS. Higher response rates were observed for a subset of patients with focal epileptiform discharges.

A novel case of MSTO1 gene related congenital muscular dystrophy with progressive neurological involvement.

Recessive mutations in the MSTO1 gene, encoding for a mitochondrial distribution and morphology regulator, have been recently described in a very limited number of patients with multisystem involvement, mostly characterized by myopathy or dystrophy, cerebellar ataxia, pigmentary retinopathy and raised creatine kinase levels. Here we report an additional patient with recessive MSTO1-related muscular dystrophy (MSTO1-RD), and clinical and radiological evidence of progressive cerebellar involvement. Whole-exome sequencing identified two novel MSTO1 missense variants, c.766C > T (p. (Arg256Trp) and c.1435C > T (p. (Pro479Ser), predicted as damaging by in silico tools. We also report a distinct pattern of selective involvement on muscle MRI in MSTO1-RD. This case confirms a consistent MSTO1-related neuromuscular phenotype and in addition suggests a progressive neurological component at least in some patients, in keeping with the mitochondrial role of the defective protein.

Clinical outcomes of two patients with a novel pathogenic variant in ASNS: response to asparagine supplementation and review of the literature.

Asparagine synthetase deficiency (ASNSD, OMIM #615574) is a rare autosomal recessive neurometabolic inborn error that leads to severe cognitive impairment. It manifests with microcephaly, intractable seizures, and progressive cerebral atrophy. Currently, there is no established treatment for this condition. In our pediatric cohort, we discovered, by whole-exome sequencing in two siblings from Turkey, a novel homozygous missense mutation in asparagine synthetase at NM_133436.3 (ASNS_v001): c.1108C>T that results in an amino acid exchange p.(Leu370Phe), in the C-terminal domain. After identification of the metabolic defect, treatment with oral asparagine supplementation was attempted in both patients for 24 months. Asparagine supplementation was well tolerated, and no further disease progression was observed during treatment. One of our patients showed mild developmental progress with increased levels of attention and improved nonverbal communication. These results support our hypothesis that asparagine supplementation should be further investigated as a treatment option for ASNSD. We further reviewed all previously reported ASNSD cases with regard for their clinical phenotypes and brain imaging findings to provide an essential knowledge base for rapid diagnosis and future clinical studies.

Diagnostic Pathway to Nonsense Mutation Dystrophinopathy: A Tertiary-Center, Retrospective Experience.

Up to 15% of Duchenne's muscular dystrophy (DMD) is caused by nonsense mutations (nm-DMD). In this study, we aimed to evaluate the age at diagnosis, presentations, and diagnostic approach in 43 nm-DMD boys. The mean age at presentation and diagnosis was 3 years and 4 years, respectively. Presenting signs or symptoms were asymptomatic creatine kinase (CK) elevation (40%), muscle weakness (30%), motor delay (18%), and walking difficulties (12%). Multiplex polymerase chain reaction (PCR) of the most commonly deleted exons were negative (n = 17), and muscle biopsy was consistent with dystrophinopathy (n = 24). In all patients, multiplex ligation-dependent probe amplification (MLPA) followed by direct sequencing of all exons, revealed nm-DMD. Mean age at genetic diagnosis was 6 years 8 months. Patients were evaluated in two-time periods, between 2006 and 2011 (Group I: n = 10) and 2011 and 2017 (Group II: n = 33). The mean age at diagnosis/genetic confirmation in Group I and in Group II was 3 years 9 months/10 years, and 4 years 1 month/5 years 9 months, respectively. Most frequently performed first step diagnostic tests in Group I and Group II were muscle biopsy and MLPA.Our study reflects the change in the age at genetic diagnosis and diagnostic approach to nm-DMD depending on the advances and availability of genetic testing.

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.

Congenital mirror movements in a patient with alpha-dystroglycanopathy due to a novel POMK mutation.

Dystroglycanopathies are a heterogeneous group of muscular dystrophies often associated with variable brain and eye involvement. Glycosylated alpha-dystroglycan (ADG) plays a key role in the development and stability of basement membranes as well as organizing axon guidance in the central nervous system. Congenital mirror movements, either isolated or in association with several genetic syndromes, are defined as inability to perform unimanual movements. We report an adolescent boy with limb-girdle muscular dystrophy due to ADG deficiency and coexisting congenital mirror movements. Genetic work-up revealed a novel homozygous missense mutation in the protein O-mannose kinase (POMK) gene. To our knowledge, this is the first patient in the literature with POMK mutation and congenital mirror movements.

Reversible Hypertensive Myelopathy-The Spinal Cord Variant of Posterior Reversible Encephalopathy Syndrome.

The posterior reversible encephalopathy syndrome (PRES) is a well-known clinical and radiologic entity mainly affecting the territory of the posterior cerebral circulation. Spinal cord involvement is extremely rare, and as of yet, only a few cases have been reported in the literature. The present case describes a reversible, longitudinal spinal cord lesion in a patient with high blood pressure. We discuss the differential diagnosis of longitudinal myelopathy and focus on the clinical presentation, diagnosis, and management of the "spinal cord variant of PRES."

Variants in the Oxidoreductase PYROXD1 Cause Early-Onset Myopathy with Internalized Nuclei and Myofibrillar Disorganization.

This study establishes PYROXD1 variants as a cause of early-onset myopathy and uses biospecimens and cell lines, yeast, and zebrafish models to elucidate the fundamental role of PYROXD1 in skeletal muscle. Exome sequencing identified recessive variants in PYROXD1 in nine probands from five families. Affected individuals presented in infancy or childhood with slowly progressive proximal and distal weakness, facial weakness, nasal speech, swallowing difficulties, and normal to moderately elevated creatine kinase. Distinctive histopathology showed abundant internalized nuclei, myofibrillar disorganization, desmin-positive inclusions, and thickened Z-bands. PYROXD1 is a nuclear-cytoplasmic pyridine nucleotide-disulphide reductase (PNDR). PNDRs are flavoproteins (FAD-binding) and catalyze pyridine-nucleotide-dependent (NAD/NADH) reduction of thiol residues in other proteins. Complementation experiments in yeast lacking glutathione reductase glr1 show that human PYROXD1 has reductase activity that is strongly impaired by the disease-associated missense mutations. Immunolocalization studies in human muscle and zebrafish myofibers demonstrate that PYROXD1 localizes to the nucleus and to striated sarcomeric compartments. Zebrafish with ryroxD1 knock-down recapitulate features of PYROXD1 myopathy with sarcomeric disorganization, myofibrillar aggregates, and marked swimming defect. We characterize variants in the oxidoreductase PYROXD1 as a cause of early-onset myopathy with distinctive histopathology and introduce altered redox regulation as a primary cause of congenital muscle disease.

Cerebral Hyperperfusion in a Child with Stroke-Like Migraine Attacks after Radiation Therapy Syndrome.

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare complication of cranial radiotherapy characterized by migraine-like headache and transient neurological deficits with typical gyriform enhancement on magnetic resonance imaging (MRI). Potential underlying mechanisms are endothelial damage or dysfunction, vascular instability, vasospasm and, neuronal dysfunction.We report an 11-year-old girl with a primary diagnosis of medulloblastoma presented with acute-onset severe headache and left-sided weakness, 20 months after completing cranial radiotherapy. MRI demonstrated unilateral cortical swelling and concomitant leptomeningeal, gyral contrast enhancement, and MR perfusion imaging showed increased cortical perfusion in the right temporo-parieto-occipital region. Her symptoms resolved spontaneously over several days.SMART syndrome appears to be a reversible, long-term complication of cranial radiotherapy. So far, a limited number of pediatric patients with SMART syndrome have been reported. Prompt recognition of clinical signs and radiological imaging of SMART syndrome may help prevent unnecessary interventions and initiate appropriate diagnostic workup and management.

Clinical characteristics of type 1 diabetes over a 40 year period in Turkey: secular trend towards earlier age of onset.

UNLABELLED: OBJective: To determine the demographic and clinical characteristics of type 1 diabetes (T1D) in the past two decades, and to analyze changing trends over the past 40 years. METHODS: Patients with a diagnosis of T1D in 1990-2010 were included. Patients diagnosed in the first half of the period comprised Period I, and those from the second half comprised Period II. Age at onset, gender, seasonal distribution, infectious etiology, and clinical picture at onset are analyzed and compared in two periods. In addition, we compared these data with that of the preceding two decades (1969-1991), which was reported in a previous publication. RESULTS: A total of 354 children with T1D were included in the study. The median age at diagnosis of T1D was 7 years in the period 1990-2010 in comparison to 9.5 years during the period 1969-1991. Patients were diagnosed mostly in winter and autumn, and 32.3% of the children had an infection at the time of diagnosis. Frequency of diabetic ketoacidosis was 50.8% at diagnosis. The peak age at onset was 4 to 6 years. CONCLUSIONS: Our study provides substantial information about the clinical characteristics of Turkish children. The age of onset of T1D decreased in the past 20 years, as observed in other parts of the world. Our findings also suggest seasonality at onset of T1D. This study shows the changes of demographic and clinical characteristics of T1D in central and northeastern parts of our country over a 40 year period.