The Complex Genetic Landscape of Hereditary Ataxias in Turkey and Implications in Clinical Practice

BACKGROUND

The genetic and epidemiological features of hereditary ataxias have been reported in several populations; however, Turkey is still unexplored. Due to high consanguinity, recessive ataxias are more common in Turkey than in Western European populations.

OBJECTIVE

To identify the prevalence and genetic structure of hereditary ataxias in the Turkish population.

METHODS

Our cohort consisted of 1296 index cases and 324 affected family members. Polymerase chain reaction followed by Sanger sequencing or fragment analysis were performed to screen for the trinucleotide repeat expansions in families with a dominant inheritance pattern, as well as in sporadic cases. The expansion in the frataxin (FXN) gene was tested in all autosomal recessive cases and in sporadic cases with a compatible phenotype. Whole-exome sequencing was applied to 251 probands, selected based on the family history, age of onset, and phenotype.

RESULTS

Mutations in known ataxia genes were identified in 30% of 1296 probands. Friedreich's ataxia was found to be the most common recessive ataxia in Turkey, followed by autosomal recessive spastic ataxia of Charlevoix-Saguenay. Spinocerebellar ataxia types 2 and 1 were the most common dominant ataxias. Whole-exome sequencing was performed in 251 probands with an approximate diagnostic yield of 50%. Forty-eight novel variants were found in a plethora of genes, suggesting a high heterogeneity. Variants of unknown significance were discussed in light of clinical data.

CONCLUSION

With the large sample size recruited across the country, we consider that our results provide an accurate picture of the frequency of hereditary ataxias in Turkey. © 2021 International Parkinson and Movement Disorder Society.

Extreme delta brush activity: Could it be a marker for early diagnosis and prognosis of anti- NMDA (N-methyl-D-aspartate) encephalitis?

Autoimmune encephalitis should be excluded in unexplained encephalitis. A significant portion of autoimmune encephalitis in childhood is anti- NMDA encephalitis. However, neuroimaging and routine diagnostic tests are inadequate, diagnosis sholud be confirmed by the demonstration of autoantibodies. The treatment may be delay in this process. Extreme delta brush waves are unique electroencephalography pattern, seen in some of Anti-NMDA encephalitis, useful for early diagnosis. Extreme delta brush activity is associated with prolonged hospitalization and illness. Despite of these, the specificity and sensitivity of this pattern is not-known clearly. We present a five years old boy with the loss of consciousness, involuntary movements, intermittant generalized tonic clonic seizures and extreme delta brush activity in electroencephalography.

Prevalence and severity of malnutrition in pediatric neurology outpatients with respect to underlying diagnosis and comorbid nutrition and feeding related problems

Tekin H, Tekgül H, Yılmaz S, Arslangiray D, Reyhan H, Serdaroğlu G, Gökben S. Prevalence and severity of malnutrition in pediatric neurology outpatients with respect to underlying diagnosis and co-morbid nutrition and feeding related problems. Turk J Pediatr 2018; 60: 709-717. This study aimed to determine prevalence and severity of malnutrition with respect to underlying diagnosis and co-morbid nutrition and feeding related problems in pediatric neurology outpatients. A total of 1,057 pediatric neurology outpatients (7.2±5.4 years, 56.9% males) were included. Data on patient demographics, neurological diagnosis, anthropometrics and Nutritional Questionnaire (NQ) for co-morbid feeding difficulties and nutritional problems were recorded. Epilepsy (45.2%) was the most common diagnosis, while prevalence of acute malnutrition was 17.7%. Nutritional support resulted in a significant decrease in the percentage of malnourished patients (from 17.1% to 6.7%, p˂0.001) and significant improvement in weight for height scores (increased to 81.42±8.17, p=0.045). In NQ-10 item assessment, at least one item was positive in 66.0% (gastrointestinal in 54.3%) of acutely malnourished patients, more commonly in severe acute malnutrition. NQ 4- item set of `red flags` revealed that prolonged meal time, meal time stressful to child or parent, lack of weight gain not just weight loss and cough during feeding were evident in 45.2%, 46.8%, 36.7% and 14.8% of patients with acute malnutrition, respectively; and more common in patients with severe malnutrition. NQ 4-item set of `red flags` was associated with high sensitivity (95%) and specificity (88%) in detection of malnutrition. In conclusion, our findings in a cohort of pediatric neurology outpatients revealed that 17.1% of overall patients were acutely malnourished along with higher prevalence of malnutrition in underlying diagnosis of cerebral palsy and higher likelihood of nutritional problems and feeding difficulties in severe malnutrition. Given the association of 6-month nutritional support with improved anthropometrics and decreased percentage of malnourished patients, our findings indicate that increased awareness of nutritional status and nutritional support is essential for the care of neurologically impaired children with potential benefit of identifying early feeding/swallowing related signs of malnutrition.

Characteristics of pediatric multiple sclerosis: The Turkish pediatric multiple sclerosis database

OBJECTIVE

To document the clinical and paraclinical features of pediatric multiple sclerosis (MS) in Turkey.

METHODS

Data of MS patients with onset before age 18 years (n = 193) were collected from 27 pediatric neurology centers throughout Turkey. Earlier-onset (<12 years) and later-onset (≥12 years) groups were compared.

RESULTS

There were 123 (63.7%) girls and 70 (36.3%) boys aged 4-17 years, median 14 years at disease onset. Family history of MS was 6.5%. The first presentation was polysymptomatic in 55.4% of patients, with brainstem syndromes (50.3%), sensory disturbances (44%), motor symptoms (33.2%), and optic neuritis (26.4%) as common initial manifestations. Nineteen children had facial paralysis and 10 had epileptic seizures at first attack; 21 (11%) were initially diagnosed with acute disseminated encephalomyelitis (ADEM). Oligoclonal bands were identified in 68% of patients. Magnetic resonance imaging revealed periventricular (96%), cortical/juxtacortical (64.2%), brainstem (63%), cerebellum (51.4%), and spinal cord (67%) involvement. Visual evoked potentials (VEP) were abnormal in 52%; serum 25-hydroxyvitamin D levels were low in 68.5% of patients. The earlier-onset group had a higher rate of infection/vaccination preceding initial attack, initial diagnosis of ADEM, longer interval between first 2 attacks, and more disability accumulating in the first 3 years of the disease.

CONCLUSION

Brainstem and cerebellum are common sites of clinical and radiological involvement in pediatric-onset MS. VEP abnormalities are frequent even in patients without history of optic neuropathy. Vitamin D status does not appear to affect the course in early disease. MS beginning before 12 years of age has certain characteristics in history and course.

Genetic Landscape of Congenital Myasthenic Syndromes From Turkey: Novel Mutations and Clinical Insights

Congenital myasthenic syndromes are clinically and genetically heterogeneous disorders of neuromuscular transmission. Most are treatable, but certain subtypes worsen with cholinesterase inhibitors. This underlines the importance of genetic diagnosis. Here, the authors report on cases with genetically proven congenital myasthenic syndromes from Turkey. The authors retrospectively reviewed their experience of all patients with congenital myasthenic syndromes, referred over a 5-year period (2011-2016) to the Child Neurology Department of Dokuz Eylül University, Izmir, Turkey. In addition, PubMed was searched for published cases of genetically proven congenital myasthenic syndromes originating from Turkey. In total, the authors identified 43 (8 new patients, 35 recently published patients) cases. Defects in the acetylcholine receptor (n = 15; 35%) were the most common type, followed by synaptic basal-lamina associated (n = 14; 33%) and presynaptic syndromes (n = 10; 23%). The authors had only 3 cases (7%) who had defects in endplate development. One patient had mutation GFPT1 gene (n = 1; 2%). Knowledge on congenital myasthenic syndromes and related genes in Turkey will lead to prompt diagnosis and treatment of these rare neuromuscular disorders.

Seizures due to high dose camphor ingestion

Camphor is a cyclic ketone of the hydro aromatic terpene group. Today it is frequently used as a prescription or non-prescription topical antitussive, analgesic, anesthetic and antipruritic agent. Camphor which is considered an innocent drug by parents and physicians is a common household item which can lead to severe poisoning in children even when taken in small amounts. Neurotoxicity in the form of seizures can ocur soon after ingestion. A two-year old female patient who presented with a complaint of generalized tonic-clonic seizures after oral ingestion of camphor is presented.

Turkish cases of early infantile epileptic encephalopathy: two novel mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene

Cyclin-dependent kinase-like 5 gene-related epileptic encephalopathy is gradually becoming better known in child neurology practice. The related gene mutations cause early infantile epileptic encephalopathy characterized by intractable epilepsy, severe mental retardation and, later, the development of Rett syndrome-like features. Herein, we report the first two Turkish cases of cyclin-dependent kinase-like 5 gene-related epileptic encephalopathy with novel mutations in exon 8, which is located in the catalytic domain of the gene.

Electrophysiologic assessment of spasticity in children using H-reflex

We investigated a possible correlation between Hoffmann's reflex (H-reflex) and the Modified Ashworth Scale (MAS) in children with spasticity. H-reflex latencies, amplitudes (H amplitude), Hmax/Mmax amplitude, and MAS were simultaneously measured in 30 children who had bilateral spasticity on the lower extremities. Children with MAS scores of 1 and +1 composed Group I (n=11), and children with MAS scores of 2 and 3 composed Group II (n=26) and Group III (n=23), respectively. The H-reflex latencies were significantly shorter and Hmax/Mmax ratios were significantly higher in patients with cerebral palsy than controls irrespective of the degree of the MAS. The H-reflex latencies in patients with MAS of 1 or +1 were significantly longer than in patients with MAS of 2. Other than between these two groups for H-reflex latencies, no significant differences were revealed among the three different MAS groups for either H-reflex latencies or Hmax/Mmax ratios. There is a positive correlation between spasticity assessed by MAS and H-reflex. We concluded that the H-reflex is a reliable electrophysiologic test for assessment of spasticity in children.

Changing views of cerebral palsy over 35 years: the experience of a center

In this study, it was aimed to evaluate the demographic and clinical characteristics of cerebral palsy (CP) cases over a 35-year period. Findings of 442 patients with CP followed from 1995 to 2006 (Group 2) were compared with 208 patients with CP followed between 1972 and 1994 (Group 1) in the same pediatric neurology division. Ratios of both prematurity (38% vs. 17.7%) and very low birth weight (VLBW) infants (13.8% vs. 1.5%) significantly increased in Group 2. There was also a four-fold increase in cesarean delivery in Group 2 (42.3% vs. 9.6%). A significant increase in the rate of early diagnosis during the first year was also found in this group (56.9% vs. 39.4%). The rate of spastic diparesis cases has significantly increased (33.7% vs. 7.7%), while the rate of spastic tetraparesis cases has significantly decreased (63.5% vs. 37.3%). It was seen that preventable risk factors continue today.

Syncope or seizure? The diagnostic value of synchronous tilt testing and video-EEG monitoring in children with transient loss of consciousness

Syncope and seizure are frequently encountered problems in daily neurology practice, and they also share common findings such as transient loss of consciousness and atonia. Sometimes, it is difficult to make a differentiation between the two entities using only clinical findings. In this study, nineteen patients aged between 5 and 20 years who had recurrent transient loss of consciousness and occasional atonic events were examined with synchronous tilt testing and video-EEG recordings. Eleven patients were initially diagnosed with epilepsy, and they were given antiepileptic drugs. Eight patients displayed neurally mediated syncope during examination. Four of the eight patients had cardioinhibitory syncope type 2B. Three-fourths of the patients with syncope had been initially diagnosed with epilepsy and were prescribed antiepileptic drugs. One patient with cardioinhibitory syncope who had prolonged asystole and frequent attacks needed a cardiac pacemaker. Following implantation, she had no new attacks. Synchronous tilt testing and video-EEG recordings give more information than doing them separately, and they are helpful in the differential diagnosis of syncope and seizure.

Use of buspirone and fluoxetine for breathing problems in Rett syndrome

Rett syndrome is a severe neurodevelopmental disease with a prevalence of 0.88 per 10,000 girls aged 5-18 years, and is often caused by mutations in methyl-cytosine-phosphate-guanine (CpG)-binding protein 2. Disorder of respiratory control is a prominent feature of Rett syndrome. Brainstem serotoninergic neurons are known to play an important role in the arrangement of breathing rhythm and pattern. We present a patient whose severe hyperventilation and apneic attacks resolved with the concomitant treatment of fluoxetine and buspirone. To our knowledge, we describe the first patient with Rett syndrome to receive fluoxetine for respiratory problems.

Video/EEG recording of myoclonic absences in GLUT1 deficiency syndrome with a hot-spot R126C mutation in the SLC2A1 gene

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is an inborn error of brain energy metabolism characterized by impaired glucose transport into the brain. A classic phenotype comprising epilepsy, mental retardation, an often paroxysmal disorder, and several subtypes has been described. Although typical absences are frequent in GLUT1DS, myoclonic absence seizures are rarely reported. Here we describe a novel Turkish patient with a hot-spot mutation (R126C) in the SLC2A1 gene who presented with unusual myoclonic absence epilepsy and paroxysmal shivering. The case is discussed in view of eight other cases carrying the R126C mutation.

An inherited nonsense R1645X mutation in neuronal sodium channel alpha1-subunit gene in a Turkish patient with severe myoclonic epilepsy of infancy

Severe myoclonic epilepsy of infancy (SMEI) is a well-known catastrophic epileptic syndrome. Several mutations of the sodium channel alpha 1 subunit (SCN1A ) gene were reported in patients with SMEI. Most of the mutations were DE NOVO. Inherited truncating mutations are very rare. Here a patient with a new nonsense mutation (c.4933 C>T; p.R1645X) of the gene is described. This mutation was inherited from the father who had only febrile seizures during childhood.

Chronic inflammatory demyelinating polyradiculopathy: an atypical pediatric case complicated with phrenic nerve palsy

An atypical form of chronic inflammatory demyelinating polyneuropathy (CIDP) complicated with phrenic nerve palsy is presented with clinical and electrophysiologic features. A seven-year-old girl had initial presentation mimicking Guillain-Barré syndrome based on electrophysiologic characteristics. Between 7-11 years of age, she had five recurrences of subacute onset of weakness which usually developed over at least 2-4 months and progressed to loss of ambulation and to respiratory insufficiency. Radiologic examinations revealed unilateral phrenic nerve palsy associated with CIDP. Our patient demonstrated the rare association of CIDP and phrenic nerve palsy, resulting in diaphragmatic paralysis and respiratory failure.

Miller Fisher syndrome: a case with pattern of pure sensory polyneuropathy concomitant with anti-GQ1B antibody

Miller Fisher syndrome is characterized by the acute onset of ophthalmoplegia, ataxia, and areflexia. Anti-GQ1b antibodies are useful markers for the differential diagnosis of Miller Fisher syndrome. We describe the case of a seven-year-old male who presented with a four-day history of diplopia and ophthalmoplegia following a febrile flu-like illness with sore throat. On examination he was found to have ataxia, areflexia and ophthalmoplegia, and a diagnosis of Miller Fisher syndrome was made after the exclusion of other conditions and concomitant with electrophysiological findings on electromyography. Although this disorder has a rare incidence, it should still be considered in the differential diagnosis in our country.

Severe juvenile dermatomyositis: two patients complicated with extra musculocutaneous involvement

Here we report two patients with severe juvenile dermatomyositis (JDM) complicated with extra musculocutaneous involvement. The first case (a 10-year-old boy) had unusual initial presentation of JDM complicated with interstitial lung disease documented with high-resolution computed tomography. He had a rapidly progressive course and died in 7 weeks after the onset of the disease despite steroid and immunosuppressive treatment. The second case (a 14-year-old boy) was presented with myositis complicated with hepatitis. He also had a chronic course of JDM with unfavorable outcome. It appears that the prognosis of patients with severe JDM is related with the degree of autoimmune vasculitis on extra musculocutaneous involvement.

Landau-Kleffner syndrome beginning with stuttering: case report

Landau-Kleffner syndrome is marked by an acquired aphasia in children who have had normal language and motor development. A 3.5-year-old girl was referred to our clinic with stuttering. She was diagnosed as having benign myoclonic epilepsy of infancy at 3.5 months of age and treated with valproic acid. Her electroencephalogram (EEG) returned to normal at the end of the first year. The therapy was stopped after a 2-year seizure-free period. She started to stutter prominently 3 months after the discontinuation of antiepilepsy drugs. She had no verbal agnosia. Her EEG revealed multiple spike and wave discharges. She was diagnosed as having Landau-Kleffner syndrome. Her previous epilepsy history had contributed to her having obtained an EEG in the early period. We suggest that if a child with normal language function starts to stutter, Landau-Kleffner syndrome must be considered in the differential diagnosis.

Dissection of aorta: a pediatric case report

We present a 15-year-old boy who developed sudden walking disability and sensory loss. He could not stand up on his feet and had no feeling following a sudden fall while playing basketball. He had been referred to a local hospital with these symptoms. In his physical examination absence of deep tendon reflexes and sensory loss were noted. His arterial blood pressure was 210/160 mmHg. He was transferred to our hospital with these findings and diagnosis of Guillain-Barré syndrome and hypertensive encephalopathy. There was sudden onset of sensory loss, walking disability and history of trauma. In the following hours hematuria, back pain and lower extremity ischemia developed. We suspected spinal artery injury based on the findings. Dissection of descending aorta was established with the help of magnetic resonance imaging of spinal region and contrasted aortography. The patient went to surgery immediately. He was lost on the second day after operation because of malperfusion. We report this case because dissecting aorta is very rare in the pediatric age group. High index of suspicion and early aortography are needed to diagnose aorta dissection.