Shared Biological Pathways and Processes in Patients with Intellectual Disability: A Multicenter Study.

BACKGROUND: Although the underlying genetic causes of intellectual disability (ID) continue to be rapidly identified, the biological pathways and processes that could be targets for a potential molecular therapy are not yet known. This study aimed to identify ID-related shared pathways and processes utilizing enrichment analyses. METHODS: In this multicenter study, causative genes of patients with ID were used as input for Disease Ontology (DO), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. RESULTS: Genetic test results of 720 patients from 27 centers were obtained. Patients with chromosomal deletion/duplication, non-ID genes, novel genes, and results with changes in more than one gene were excluded. A total of 558 patients with 341 different causative genes were included in the study. Pathway-based enrichment analysis of the ID-related genes via ClusterProfiler revealed 18 shared pathways, with lysine degradation and nicotine addiction being the most common. The most common of the 25 overrepresented DO terms was ID. The most frequently overrepresented GO biological process, cellular component, and molecular function terms were regulation of membrane potential, ion channel complex, and voltage-gated ion channel activity/voltage-gated channel activity, respectively. CONCLUSION: Lysine degradation, nicotine addiction, and thyroid hormone signaling pathways are well-suited to be research areas for the discovery of new targeted therapies in ID patients.

Clinical and genetic spectrum from a prototype of ciliopathy: Joubert syndrome.

OBJECTIVE: Joubert syndrome is a neurodevelopmental disorder with a distinctive hindbrain malformation called molar tooth sign, causing motor and cognitive impairments. More than 40 genes have been associated with Joubert syndrome. We aim to describe a group of Joubert syndrome patients clinically and genetically emphasizing organ involvement. METHODS: We retrospectively collected clinical information and molecular diagnosis data of 22 patients with Joubert syndrome from multiple facilities. Clinical exome or whole-exome sequencing were performed to identify causal variations in genes. RESULTS: The most common variants were in the CPLANE1, CEP290, and TMEM67 genes, and other causative genes were AHI1, ARMC9, CEP41, CSPP1, HYLS1, KATNIP, KIAA0586, KIF7, RPGRIP1L, including some previously unreported variants in these genes. Multi-systemic organ involvement was observed in nine (40%) patients, with the eye being the most common, including Leber's congenital amaurosis, ptosis, and optic nerve coloboma. Portal hypertension and esophageal varices as liver and polycystic kidney disease and nephronophthisis as kidney involvement was encountered in our patients. The HYLS1 gene, which commonly causes hydrolethalus syndrome 1, was also associated with Joubert syndrome in one of our patients. A mild phenotype with hypophyseal hormone deficiencies without the classical molar tooth sign was observed with compound heterozygous and likely pathogenic variants not reported before in the KATNIP gene. CONCLUSION: Some rare variants that display prominent genetic heterogeneity with variable severity are first reported in our patients. In our study of 22 Joubert syndrome patients, CPLANE1 is the most affected gene, and Joubert syndrome as a ciliopathy is possible without a classical molar tooth sign, like in the KATNIP gene-affected patients.

Homozygous exonic and intragenic NRXN1 deletion presenting as either West syndrome or autism spectrum disorder in two siblings.

Neurexins (NRXNs) are cell-adhesion molecules that play critical roles in establishing and maintaining synaptic connections. Humans have three NRXN genes (NRXN1, NRXN2, NRXN3) and heterozygous intragenic microdeletions involving NRXN1 have been associated with autism spectrum disorder, attention deficit hyperactivity disorder, intellectual disability, seizures, schizophrenia, and bipolar disorder. Bi-allelic loss in NRXN1 produces a recessive and severe phenotype. We would like to describe the clinical, electroencephalographic, and genetic findings of two siblings, one with a neurodevelopmental disorder with infantile spasms and the other with autism spectrum disorder, having homozygous exonic NRXN1 deletion. A suspicious variant was not detected in the whole exome-sequencing but copy number variation analysis revealed NRXN1 exon 2-5 homozygous deletion (chr2:51149007-51255411; 106.404 kb) in both siblings. Neurodevelopmental disorder with infantile spasms and autism spectrum disorder in two siblings with homozygous NRXN1 deletion display intrafamilial phenotypic variation. Bi-allelic/homozygous NRXN1 exonic deletions are responsible for a spectrum from significant intellectual disability to epileptic encephalopathy, even within the same family. Array comparative genomic hybridization should be the first genetic testing in epileptic encephalopathy although we reached the diagnosis with next-generation sequencing and later copy number variation analysis.

First afebrile seizures: Clinical and radiological view with emergent testing.

BACKGROUND: The first afebrile seizures in children are an important and common reason for emergency department admissions. We aim to examine the presentation, laboratory/neurodiagnostic investigation, and emergency management of children with first afebrile seizures. METHODS: The retrospective study included 333 patients aged 1 month to 18 years admitted with a first afebrile seizure to the pediatric emergency department of Prof. Dr. Cemil Tascioglu City Hospital between January 2017 and January 2020. Age, gender, seizure duration and type, treatments for seizures, laboratory, neurophysiological, and radiological investigations, ward or intensive care unit hospitalizations, and antiepileptic drugs on discharge were recorded. RESULTS: The average age of the patients was 81.6 ± 62.9 months; 187 (56.2%) were male and 146 (43.8%) were female. Two hundred and sixty-one (78.4%) patients had only one seizure. In 45 (13.5%) of the patients, the seizure recurred in the emergency department. Hypoglycemia, hyponatremia, and hypocalcemia were detected in 13 (3.9%) patients. Patients with clinically significant cranial computed tomography results were at an increased risk for seizures lasting longer than 5 min. Patients with focal seizures had more recurrences, were given more antiepileptic drugs during the emergency, had better known etiology, more intensive care unit hospitalization, and greater post-discharge antiepileptic drug prescription. CONCLUSIONS: Biochemical abnormalities remain in the background in the etiology of afebrile seizures. Patients with abnormal neuroimaging on cranial tomography tended to have longer seizures. Patients with focal seizures followed a more complicated course as they had more recurrences and more hospitalization in the intensive care unit.

Cytotoxic lesions of the corpus callosum in children: Etiology, clinical and radiological features, and prognosis.

OBJECTIVES: Cytotoxic lesions of the corpus callosum (CLOCCs) are secondary lesions associated with entities like infection manifested by restricted diffusion on diffusion-weighted cranial magnetic resonance imaging. Our objectives are to evaluate the clinic-radiological spectrum of pediatric patients with cytotoxic lesions of the corpus callosum (CC). METHODS: Children (0-18 years) admitted between February 2017 and May 2020 with splenial lesions showing diffusion restriction on MRI, either isolated or within involvement of other parts of the brain, were included retrospectively. The primary lesions of the CC (e.g. acute disseminated encephalomyelitis, acute ischemic infarction, and glioblastoma multiforme) were excluded. CLOCCs were divided into infection-associated, metabolic disorder-associated, and trauma-associated lesions, as well as CLOCCs involving other entities. Data were collected from the medical databases. RESULTS: Forty-one patients were determined to have CLOCCs. Twenty-five (61%) were infection-associated, nine (22%) were trauma-associated, and three (7%) were metabolic disorder-associated cases, including 2 inherited disorders of metabolism. There were four (10%) patients with other entities, three with epilepsy, and one had an apparent life-threatening event. Six patients had a known etiology among the infection-associated group; one had multisystem inflammatory syndrome caused by COVID-19 and one had been infected by COVID-19 without any complications. All the infection-associated patients with isolated splenial lesions recovered totally, although six patients required intensive care hospitalization. Four trauma-associated patients had sequela lesions. CONCLUSIONS: CLOCCs are associated with a spectrum of diseases, including the new coronavirus, COVID-19 infection. Infection-associated CLOCCs has the best prognosis, although severe cases may occur. Sequelae are possible based on the etiology.

The relationship between epileptic seizure and melatonin in children.

OBJECTIVE: Studies about the relationship between epileptic seizures (ESs) and melatonin are limited in children and have been performed in heterogeneous patient groups and with different methods. In this study, it was planned to investigate this relationship according to seizure and epilepsy characteristics. MATERIAL AND METHODS: In 91 children with ES, serum melatonin levels were measured within half an hour following the seizure and on a seizure-free day. Seizures were categorized according to the diagnosis, semiology, etiology, duration, electroencephalography (EEG) findings, and response to treatment. Melatonin levels were compared between each group and control group. In addition, basal melatonin levels of 21 patients with electrical status epilepticus in sleep (ESES) were compared with a control group. RESULTS: Basal melatonin levels were found to be lower in children with ESs and ESES group compared with the control group (p < 0.001, p < 0.001). Likewise, similar results were obtained in subgroups except for remote symptomatic etiology, severe EEG findings, and refractory epilepsy. No significant difference was observed between basal and postseizure levels of melatonin. CONCLUSION: This is the first study to reveal the relationship between ESs and basal melatonin levels according to all the characteristics of seizure and epilepsy in the largest patient group. It also demonstrates the need for more detailed studies on the role of melatonin in the pathogenesis of both ESs and ESES, which may provide a basis for a future treatment.

A case of juvenile Canavan disease with distinct pons involvement.

BACKGROUND: Canavan disease is a genetic neurodegenerative leukodystrophy that results in the spongy degeneration of the white matter. Its key clinical features in the infantile form are developmental delay, visual problems and macrocephaly. Congenital and juvenile forms have also been described. PATIENT DESCRIPTION: We report on a 13-year-old boy who is a high school student in a public school. He was diagnosed with juvenile Canavan disease, presenting with intentional tremor as the only clinical finding. RESULTS: Magnetic resonance imaging revealed mainly the involvement of the caudate nucleus and pons extending to the mesencephalon and also the putamen and the thalamus, with no apparent signal increase in the cerebral white matter. A homozygous p.Gly274Arg (c.820A>G) missense mutation was identified. CONCLUSION: Juvenile Canavan disease with mainly pons involvement has not been published before. Pons, caudate nucleus and basal ganglia involvement without any white matter being involved could be expected in juvenile Canavan disease as a rare form of the disease.

Predictive factors of drug-resistant epilepsy in children presenting under 2 years of age: experience of a tertiary center in Turkey.

Population-based studies report that children with epilepsy have relatively better prognosis than those with an onset at infancy, though studies about this period are limited. We aimed to evaluate the etiology in infant epilepsy less than 2 years of age and foreseeable risk factors for anti-epileptic drug resistance. We evaluated the patients who were presented to the division of pediatric neurology in our university hospital with seizures when they were between 1 and 24 months of age and diagnosed as epilepsy. Two hundred and twenty-nine patients (110 male and 119 female) who were diagnosed between the ages of 1-24 months were included in the study. The etiologies were structural (n = 55;24%), genetic (n = 29;12.7%), metabolic (n = 27;11.7%), and infectious (n = 8;3.5%), and it was unknown in 110 patients (48%). One-hundred and forty (61%) patients met the criteria for drug-resistant epilepsy (DRE). Multivariate logistic regression analysis showed that developmental delay at onset (OR 3.9, 95% CI 1.22, 12.47, p = 0.021), multifocal epileptiform discharges (OR 2.8, 95% CI 1.1, 7.44, p = 0.031), and history of status epilepticus (OR 32.9, 95% CI 3.8, 285.35, p = 0.001) were strong predictive factors for DRE. The epilepsy in children under 2 years of age is highly resistant to the anti-epileptic drugs, which could be related to the history of status epilepticus, developmental delay at onset, and multifocal epileptiform discharges.

Evaluation of fetal subarachnoid space using transabdominal ultrasonography and normal values during pregnancy.

OBJECTIVES: To determine the feasibility of evaluating the subarachnoid space by measuring two novel sonographic parameters in axial section using transabdominal ultrasound, in addition to the parameters previously defined in coronal section, and to construct a normal range for the subarachnoid space width in singleton healthy fetuses. METHODS: Healthy pregnant women between 20 and 29 weeks were scanned using transabdominal ultrasound. Four variables were measured for the evaluation of subarachnoid space width; sinocortical width and anterior craniocortical width in coronal plane, and lateral and posterior craniocortical width in axial plane. RESULT: The data of 154 patients were recorded. SCW could be measured in 87.6 % (135) of fetuses, while the same figure was 77.9 % (120), 96.1 % (151) and 98.1 % (148) for anterior, lateral and posterolateral CCW, respectively. The SCW and anterior CCW did not display a significant correlation with gestational age and head circumference. The mean of SCW was 1.55 ± 0.41 mm with a range of 0.85-3.87 mm. The mean anterior CCW was 1.63 ± 0.39 mm with a range of 0.85-2.82 mm. A linear regression line was plotted between gestational age and lateral CCW (r = 0.707; p < 0.0001) and posterolateral CCW (r = 0.437; p < 0.0001), and nomograms for these parameters are constructed. CONCLUSION: This study presents a novel approach for the in utero evaluation of the subarachnoid space with two measurements in axial plane using transabdominal ultrasound. The nomograms will be helpful when there is a suspicion of subarachnoid space dilatation during routine cranial scan.