Extending and outlining the genotypic and phenotypic spectrum of novel mutations of NALCN gene in IHPRF1 syndrome: identifying recurrent urinary tract infection

Infantile hypotonia with psychomotor retardation and characteristic facies 1 (IHPRF1) is caused by biallelic mutations in the NALCN gene, the major ion channel responsible for the background Na + conduction in neurons. Through whole-exome sequencing (WES), we report three novel homozygous variants in three families, including c.1434 + 1G > A, c.3269G > A, and c.2648G > T, which are confirmed and segregated by Sanger sequencing. Consequently, intron 12's highly conserved splice donor location is disrupted by the pathogenic c.1434 + 1G > A variation, most likely causing the protein to degrade through nonsense-mediated decay (NMD). Subsequently, a premature stop codon is thus generated at amino acid 1090 of the protein as a result of the pathogenic c.3269G > A; p.W1090* variation, resulting in NMD or truncated protein production. Lastly, the missense mutation c.2648G > T; p.G883V can play a critical role in the interplay of functional domains. This study introduces recurrent urinary tract infections for the first time, broadening the phenotypic range of IHPRF1 syndrome in addition to the genotypic spectrum. This trait may result from insufficient bladder emptying, which may be related to the NALCN channelosome's function in background Na + conduction. This work advances knowledge about the molecular genetic underpinnings of IHPRF1 and introduces a novel phenotype through the widespread use of whole exome sequencing.

Megaconial congenital muscular dystrophy due to CHKB gene variants, the first report of thirteen Iranian patients

Megaconial congenital muscular dystrophy (OMIM: 602,541) related to CHKB gene mutation is a newly defined rare autosomal recessive disorder, with multisystem involvement presenting from the neonatal period to adolescence. Choline kinase beta, lipid transport enzyme, catalyzes the biosynthesis of phosphatidylcholine and phosphatidylethanolamine, two major components of the mitochondrial membrane, on which respiratory enzyme activities are dependent. CHKB gene variants lead to loss-of-function of choline kinase b and lipid metabolism defects and mitochondrial structural changes. To date, many megaconial congenital muscular dystrophy cases due to CHKB gene variants have been reported worldwide. We describe thirteen Iranian megaconial congenital muscular dystrophy cases related to CHKB gene variants, including clinical presentations, laboratory and muscle biopsy findings, and novel CHKB gene variants. The most common symptoms and signs included intellectual disability, delayed gross-motor developmental milestones, language skills problems, muscle weakness, as well as autistic features, and behavioral problems. Muscle biopsy examination showed the striking finding of peripheral arrangements of large mitochondria in muscle fibers and central sarcoplasmic areas devoid of mitochondria. Eleven different CHKB gene variants including six novel variants were found in our patients. Despite the rarity of this disorder, recognition of the multisystem clinical presentations combined with characteristic findings of muscle histology can properly guide to genetic evaluation of CHKB gene.

Motor planning is not restricted to only one hemisphere: evidence from ERPs in individuals with hemiplegic cerebral palsy

The evidence for the hemispheric specialization of motor planning reveals several inconsistencies between the left-lateralized hypothesis and a distributed system across the hemispheres. We compared participants with left hemiplegic cerebral palsy (HCP) to right-handed control subjects in this study's first experiment by inviting them to perform a motor planning task. Participants were required to release the start button, grasp a hexagon, and rotate it according to the instructions. In the second experiment, we compared left-HCP subjects with right-HCP subjects inviting them to perform the same task (we used the data for left-HCP subjects from the first experiment). P2 amplitude, as well as planning time, grasping time, releasing time, and initial grip selection planning patterns, were used as outcome measures in both experiments. The first experiment revealed that controls acted more quickly and chose more effective planning patterns. Also, the P2 amplitude was smaller in left-HCP subjects than in control subjects. No significant group effect was observed in the second experiment for any movement-related measure or P2. At the neural level, however, there was an interaction between 'region' and 'group,' indicating the distinction between the two groups in the right region. The results are discussed in terms of motor planning's hemispheric distribution and individual differences in the HCP group.

Identification of novel mutations among Iranian NPC1 patients: a bioinformatics approach to predict pathogenic mutations

Background

Niemann-Pick disease type C (NPC) is a rare lysosomal neurovisceral storage disease caused by mutations in the NPC 1 (95%) or NPC2 (5%) genes. The products of NPC1 and NPC2 genes play considerable roles in glycolipid and cholesterol trafficking, which could consequently lead to NPC disease with variable phenotypes displaying a broad spectrum of symptoms.

Materials

In the present study 35 Iranian NPC unrelated patients were enrolled. These patients were first analysed by the Filipin Staining test of cholesterol deposits in cells for NPC diagnostics. Genomic DNA was extracted from the samples of peripheral blood leukocytes in EDTA following the manufacturer's protocol. All exon–intron boundaries and coding exons of the NPC1gene were amplified by polymerase chain reaction (PCR) using appropriate sets of primers. Thereafter, the products of PCR were sequenced and analysed using the NCBI database (https://blast.ncbi.nlm.nih.gov/Blast.cgi). The variants were reviewed by some databases including the Human Gene Mutation Database (HGMD) (http://www.hgmd.cf.ac.uk/ac/index.php) and ClinVar (https://www.ncbi.nlm.nih.gov/clinvar (. Moreover, all the variants were manually classified in terms of the American College of Medical Genetics and Genomics (ACMG) guideline.

Results

The sequence analysis revealed 20 different variations, 10 of which are new, including one nonsense mutation (c.406C > T); three small deletions, (c.3126delC, c.2920_2923delCCTG, and c.2037delG); and six likely pathogenic missense mutations, (c.542C > A, c.1970G > A, c.1993C > G, c.2821 T > C, c.2872C > G, and c.3632 T > A). Finally, the pathogenicity of these new variants was determined using the ACMG guidelines.

Conclusion

The present study aimed to facilitate the prenatal diagnosis of NPC patients in the future. In this regard, we identified 10 novel mutations, and verified that the majority of them occurred in six NPC1 exons (5, 8, 9, 13, 19, and 21), that should be considered with a high priority for Iranian patients' cost-effective evaluation.

Epidemiology of Guillain-Barré Syndrome in Iranian Children Aged 0-15 Years (2008-2013)

Objective

Guillain-Barré Syndrome (GBS) is an acute inflammatory polyneuropathy characterized by a rapid progressive symmetric weakness. The GBS is the most common cause of acute flaccid paralysis (AFP) in most parts of the world. This study was carried out to investigate the epidemiological features of GBS in Iranian children.

Materials & Methods

The data were extracted using the AFP surveillance system that is a national screening program to detect all cases of AFP aged 0-15 years around the country. National Population Statistics data and AFP demographic data during 2008-2013 intervals were obtained from the relevant authorities in the Ministry of Health in Iran. The GBS cases were then extracted from the aforementioned database. The Chi-square test and Fisher’s exact test were used for statistical analysis.

Results

A total of 1884 cases of GBS were identified in the study period, and the average annual incidence rate was 1.72 per 100,000 individuals. The highest incidence rate was within the range of 0-5 years. There was no statistically significant relationship between the incidence of GBS and the season in the whole country.

Conclusion

High costs of GBS treatment, morbidity and occasional mortality, and number of new cases, which is estimated to be approximately 300 individuals per year, need the particular attention of the health system.

Analysis of the HEXA, HEXB, ARSA, and SMPD1 Genes in 68 Iranian Patients

Lysosomal storage diseases (LSDs) are known as genetic disorders with an overall prevalence of 1 per 7700 live births. Sphingolipidosis, which is a subgroup of LSDs, is resulted from mutations in the coding genes of specific enzymes of sphingolipid hydrolases. The current study aimed to provide additional knowledge on the genotype of sphingolipidoses disease among Iranian patients affected by the disease. In this research, we studied 68 unrelated Iranian patients diagnosed with one kind of sphingolipidoses from 2014 to 2019. Thereafter, genomic DNA was isolated from their peripheral blood leukocytes samples in EDTA in terms of the manufacturer's protocol. All the coding exons and exon-intron boundaries of the related genes were sequenced and then analyzed using the NCBI database. Finally, they were reviewed using some databases such as the Human Gene Mutation Database (HGMD) and ClinVar ( https://www.ncbi.nlm.nih.gov/clinva ). By studying 22 MLD patients, 18 different variations of the ARSA gene were found, one of which was new including, named as c.472 T > G p. (Cys158Gly). Out of 15 Sandhoff disease (SD) patients, 11 different variations of the HEXB gene were found. Correspondingly, the c.1083-2delA was not reported earlier. By investigating 21 Iranian patients with Tay-Sachs disease (TSD), one new variant was found as c.622delG. The study of 10 Niemann-Pick disease A/B (NPDA/B (patients has led to the identification of 9 different SMPD1 gene variations, among which 3 variations were novel mutations. The results of the present study can be expanded to the genotypic spectrum of Iranian patients with MLD, SD, TSD, and NPD diseases and also used to innovate more effective methods for the detection of genetic carriers as well as diagnosing and counseling of Iranian patients affected with these disorders.

Recurrent angioedema, Guillain-Barré, and myelitis in a girl with systemic lupus erythematosus and CD59 deficiency syndrome

Background

CD59 deficiency is a congenital mutation disorder in complement pathway which can present with various manifestations.

Case presentation

Herein, we presented an adolescent 16-years-old girl with recurrent attacks of Guillain-Barre in early childhood and then recurrent attacks of angioedema, paresthesia, and myelitis. Finally, she presented with quadriplegia, malar rash, proteinuria, lymphopenia, and high titer of antinuclear antibody. So, the patient developed systemic lupus erythematosus. Furthermore, we performed whole exome sequencing which revealed homozygote mutations in CD59 for the patient and heterozygote one for her parents. CD flow cytometry showed less than 1 percent expression of CD59 on the surface of the patient’s peripheral blood cells confirming the disorder. So, she had CD59 deficiency. The patient’s episodes were managed with plasma exchanges, corticosteroids, Cyclophosphamide, and Mycophenolate Mofetil which induced and maintained remission.

Conclusion

CD59 deficiency can be presented with various clinical features such as neurologic, hematologic, dermatologic, and rheumatologic problems including systemic lupus erythematosus.

Genetics of intellectual disability in consanguineous families

Autosomal recessive (AR) gene defects are the leading genetic cause of intellectual disability (ID) in countries with frequent parental consanguinity, which account for about 1/7th of the world population. Yet, compared to autosomal dominant de novo mutations, which are the predominant cause of ID in Western countries, the identification of AR-ID genes has lagged behind. Here, we report on whole exome and whole genome sequencing in 404 consanguineous predominantly Iranian families with two or more affected offspring. In 219 of these, we found likely causative variants, involving 77 known and 77 novel AR-ID (candidate) genes, 21 X-linked genes, as well as 9 genes previously implicated in diseases other than ID. This study, the largest of its kind published to date, illustrates that high-throughput DNA sequencing in consanguineous families is a superior strategy for elucidating the thousands of hitherto unknown gene defects underlying AR-ID, and it sheds light on their prevalence.

Novel mutations in the ciliopathy-associated gene CPLANE1 (C5orf42) cause OFD syndrome type VI rather than Joubert syndrome

Mutations in CPLANE1 (previously known as C5orf42) cause Oral-Facial-Digital Syndrome type VI (OFD6) as well as milder Joubert syndrome (JS) phenotypes. Seven new cases from five unrelated families diagnosed with pure OFD6 were systematically examined. Based on the clinical manifestations of these patients and those described in the literature, we revised the diagnostic features of OFD6 and include the seven most common characteristics: 1) molar tooth sign, 2) tongue hamartoma and/or lobulated tongue, 3) additional frenula, 4) mesoaxial polydactyly of hands, 5) preaxial polydactyly of feet, 6) syndactyly and/or bifid toe, and 7) hypothalamic hamartoma. By whole or targeted exome sequencing, we identified seven novel germline recessive mutations in CPLANE1, including missense, nonsense, frameshift and canonical splice site variants, all causing OFD6 in these patients. Since CPLANE1 is also mutated in JS patients, we examined whether a genotype-phenotype correlation could be established. We gathered and compared 46 biallelic CPLANE1 mutations reported in 32 JS and 26 OFD6 patients. Since no clear correlation between paired genotypes and clinical outcomes could be determined, we concluded that patient's genetic background and gene modifiers may modify the penetrance and expressivity of CPLANE1 causal alleles. To conclude, our study provides a comprehensive view of the phenotypic range, the genetic basis and genotype-phenotype association in OFD6 and JS. The updated phenotype scoring system together with the identification of new CPLANE1 mutations will help clinicians and geneticists reach a more accurate diagnosis for JS-related disorders.

Ryanodine receptor type 3 (RYR3) as a novel gene associated with a myopathy with nemaline bodies

BACKGROUND AND PURPOSE

Nemaline myopathy (NEM) has been associated with mutations in 12 genes to date. However, for some patients diagnosed with NEM, definitive mutations are not identified in the known genes, suggesting that there are other genes involved. This study describes compound heterozygosity for rare variants in ryanodine receptor type 3 (RYR3) gene in one such patient.

METHODS AND RESULTS

Clinical examination of the patient at 22 years of age revealed a long narrow face, high arched palate and bilateral facial weakness. She had proximal weakness in all four limbs, mild scapular winging but no scoliosis. Muscle biopsy revealed wide variation in fibre size with type 1 fibre predominance and atrophy. Abundant nemaline bodies were located in perinuclear and subsarcolemmal areas, and within the cytoplasm. No likely pathogenic mutations in known NEM genes were identified. Copy number variation in known NEM genes was excluded by NEM-targeted comparative genomic hybridization array. Next-generation sequencing revealed compound heterozygous missense variants in the RYR3 gene. RYR3 transcripts are expressed in human fetal and adult skeletal muscle as well as in human brain and cauda equina samples. Immunofluorescence of human skeletal muscle revealed a 'single-row' appearance of RYR3, interspersed between the 'double rows' of ryanodine receptor type 1 (RYR1) at each A-I junction.

CONCLUSION

The results suggest that variants in RYR3 may cause a recessive muscle disease with pathological features including nemaline bodies. We characterize the expression pattern of RYR3 in human skeletal muscle and brain, and the subcellular localization of RYR1 and RYR3 in human skeletal muscle.

Clinical and Epidemiological Aspects of Multiple Sclerosis in Children

OBJECTIVE

Overall, 2%-5% of patients with multiple sclerosis (MS) experienced the first episode of disease before the age 18 years old. Since the age of onset among children is not similar to that in general population, clinicians often fail to early diagnose the disease. This study aimed to determine the epidemiological and clinical patterns of MS among Iranian children.

MATERIALS & METHODS

In this cross-sectional study carried out in Iran in 2014-2015, information was collected using a checklist with approved reliability and validity. Method sampling was consensus. Data were analyzed using frequency, mean and standard deviation indices by means of SPSS ver. 20 software.

RESULTS

Totally, 177 MS children were investigated. 75.7% of them were female. Mean (SD), minimum and maximum age of subjects were 15.9 (2), 7 and 18 yr, respectively. The most reported symptoms were sensory (28.2%), motor (29.4%), diplopia (20.3%) and visual (32.8%). Primary MRI results showed 91.5% and 53.1% periventricular and spinal cord lesions, respectively.

CONCLUSION

MS is significantly more common among women. The most common age of onset is during the second decades. Sensory and motor problems are the most symptoms, while, periventricular and spinal cord lesions are the most MRI results.

CYP2U1 mutations in two Iranian patients with activity induced dystonia, motor regression and spastic paraplegia

Hereditary spastic paraplegia (HSP) is a heterogeneous condition characterized by progressive spasticity and weakness in the lower limbs. It is divided into two major groups, complicated and uncomplicated, based on the presence of additional features such as intellectual disability, ataxia, seizures, peripheral neuropathy and visual problems. SPG56 is an autosomal recessive form of HSP with complicated and uncomplicated manifestations, complicated being more common. CYP2U1 gene mutations have been identified as responsible for SPG56. Intellectual disability, dystonia, subclinical sensory motor neuropathy, pigmentary degenerative maculopathy, thin corpus callosum and periventricular white-matter hyperintensities were additional features noted in previous cases of SPG56. Here we identified two novel mutations in CYP2U1 in two unrelated patients by whole exome sequencing. Both patients had complicated HSP with activity-induced dystonia, suggesting dystonia as an additional finding in SPG56. Two out of 14 previously reported patients had dystonia, and the addition of our patients suggests dystonia in a quarter of SPG56 patients. Developmental regression has not been reported in SPG56 patients so far but both of our patients developed motor regression in infancy.

Linkage Study Revealed Complex Haplotypes in a Multifamily due to Different Mutations in CAPN3 Gene in an Iranian Ethnic Group

Calpainopathy is an autosomal recessive form of limb girdle muscular dystrophies which is caused by mutation in CAPN3 gene. In the present study, co-segregation of this disorder was analyzed with four short tandem repeat markers linked to the CAPN3 gene. Three apparently unrelated Iranian families with same ethnicity were investigated. Haplotype analysis and sequencing of the CAPN3 gene were performed. DNA sample from one of the patients was simultaneously sent for next-generation sequencing. DNA sequencing identified two mutations. It was seen as a homozygous c.2105C>T in exon 19 in one family, a homozygous novel mutation c.380G>A in exon 3 in another family, and a compound heterozygote form of these two mutations in the third family. Next-generation sequencing also confirmed our results. It was expected that, due to the rare nature of limb girdle muscular dystrophies, affected individuals from the same ethnic group share similar mutations. Haplotype analysis showed two different homozygote patterns in two families, yet a compound heterozygote pattern in the third family as seen in the mutation analysis. This study shows that haplotype analysis would help in determining presence of different founders.

Autosomal recessive mutations in THOC6 cause intellectual disability: syndrome delineation requiring forward and reverse phenotyping

THOC6 is a part of the THO complex, which is involved in coordinating mRNA processing with export. The THO complex interacts with additional components to form the larger TREX complex (transcription export complex). Previously, a homozygous missense mutation in THOC6 in the Hutterite population was reported in association with syndromic intellectual disability. Using exome sequencing, we identified three unrelated patients with bi-allelic mutations in THOC6 associated with intellectual disability and additional clinical features. Two of the patients were compound heterozygous for a stop and a missense mutation, and the third was homozygous for a missense mutation; the missense mutations were predicted to be pathogenic by in silico analysis and modeling. Clinical features of the three newly identified patients and those previously reported are reviewed; intellectual disability is moderate to severe, and malformations are variable including renal and heart defects, cleft palate, microcephaly, and corpus callosum dysgenesis. Facial features are variable and include tall forehead, short upslanting palpebral fissures +/- deep set eyes, and a long nose with overhanging columella. These subtle facial features render the diagnosis difficult to make in isolation with certainty. Our results expand the mutational and clinical spectrum of this rare disease, confirm that THOC6 is an intellectual disability causing gene, while providing insight into the importance of the THO complex in neurodevelopment.

Diagnosis and treatment of late-onset Pompe disease in the Middle East and North Africa region: consensus recommendations from an expert group

Background

Pompe disease is a rare autosomal recessive disorder caused by a deficiency of the lysosomal enzyme alpha-glucosidase responsible for degrading glycogen. Late-onset Pompe disease has a complex multisystem phenotype characterized by a range of symptoms.

Methods

An expert panel from the Middle East and North Africa (MENA) region met to create consensus-based guidelines for the diagnosis and treatment of late-onset Pompe disease for the MENA region, where the relative prevalence of Pompe disease is thought to be high but there is a lack of awareness and diagnostic facilities.

Results

These guidelines set out practical recommendations and include algorithms for the diagnosis and treatment of late-onset Pompe disease. They detail the ideal diagnostic workup, indicate the patients in whom enzyme replacement therapy should be initiated, and provide guidance on appropriate patient monitoring.

Conclusions

These guidelines will serve to increase awareness of the condition, optimize patient diagnosis and treatment, reduce disease burden, and improve patient outcomes.

Neurodegeneration with brain iron accumulation: an overview

OBJECTIVE

Neurodegeneration with brain iron accumulation (NBIA) is a group of neurodegenerative disorder with deposition of iron in the brain (mainly Basal Ganglia) leading to a progressive Parkinsonism, spasticity, dystonia, retinal degeneration, optic atrophy often accompanied by psychiatric manifestations and cognitive decline. 8 of the 10 genetically defined NBIA types are inherited as autosomal recessive and the remaining two by autosomal dominant and X-linked dominant manner. Brain MRI findings are almost specific and show abnormal brain iron deposition in basal ganglia some other related anatomical locations. In some types of NBIA cerebellar atrophy is the major finding in MRI.

Effects of miglustat on stabilization of neurological disorder in niemann-pick disease type C: Iranian pediatric case series

Niemann-Pick disease type C is a rare neurodegenerative disorder with autosomal recessive inheritance that can be broadly categorized into different forms dependent on age at disease onset: pre-/perinatal, early infantile, late infantile, juvenile, and adolescent/adult. This study was conducted to define the age at onset, clinical manifestations, neuroimaging findings and response to treatment in 21 patients diagnosed with Niemann-Pick disease type C and managed in the neurology departments of hospitals in Tehran, Iran. The effects of miglustat on patient ambulation, fine and gross motor function, swallowing, hearing, speech, seizures, psychomotor development, and ocular movements were evaluated for up to 26 months of treatment. Ambulation, fine and gross motor movements, swallowing, speech, and supranuclear gaze palsy were generally stabilized during therapy, and psychomotor delay appeared to be improved in early- and late-infantile onset patients. However, miglustat had no effect on organomegaly or other systemic manifestations of the disease. Miglustat was well tolerated.

A novel mutation in MCPH1 gene in an Iranian family with primary microcephaly

Primary microcephaly (MCPH) is a genetic disorder in which affected individuals present with a head circumference 3 standard deviations (SDs) below the age- and sex-related mean and is accompanied by mental retardation without further associated malformations. Here we report a patient with sporadic MCPH from Northwest of Iran who was investigated for MCPH1 locus. Clinical examination and karyotype analyses were performed and microsatellite based mapping was done by using flanking and intragenic short tandem repeat (STR) markers for MCPH1 locus. For these markers the affected individual was homozygote and the parents were heterozygote. According to this pattern of allele sharing and also the cytogenetic findings, mutation screening of Microcephalin gene was performed and subsequent sequencing revealed a novel mutation in Microcephalin gene.

Efficacy of the Atkins diet as therapy for intractable epilepsy in children

BACKGROUND AND AIMS

The ketogenic diet is an effective medical therapy for intractable childhood epilepsy. However, it has drawbacks in that it restricts calories, fluids and protein. The Atkins diet may also induce ketosis without those restrictions. Our objective was to evaluate the efficacy of a modified Atkins diet in children with intractable childhood epilepsy.

METHODS

This clinical trial was conducted in 51 epileptic children aged 1 - 16 years with refractory seizures from Feb. 2004 to Oct. 2006. Outcome measures included seizure frequency and adverse reactions. Twenty-seven patients left the study for various reasons, leaving 24 who continued the Atkins diet for a minimum of three months. Carbohydrates were initially limited to 10 g/day and fats constituted 60% of the total energy requirement. All participants received vitamin and calcium supplementation.

RESULTS

Following three months of treatment with the Atkins diet, 16 patients (67%) had >50% decrease in seizure frequency, and 6 (25%) had >90% improvement, of whom 5 were seizure-free. Mean seizure frequency after the first, second and third months of treatment were significantly lower than at baseline (P values <0.001, 0.001 and 0.002, respectively).

CONCLUSION

The Atkins diet can be considered as a safe and effective alternative therapy for intractable childhood epilepsy. Atkins diet was well tolerated in our patients with rare complications and it appears to demonstrate preliminary efficacy in childhood refractory epilepsy.

Two novel mutations in SCN1A gene in Iranian patients with epilepsy

BACKGROUND AND AIMS

Epilepsy as a common chronic neurological disorder is characterized by recurrent unprovoked seizures. Febrile seizures are the most common type of epilepsy in infants and children. Our aim was the molecular analysis of SCN1A gene in affected Iranian patients with GEFS+ and Dravet syndrome diagnosed clinically to explain genotype-phenotype correlation and exact classification.

METHODS

The 34 unrelated Iranian families with epilepsy were selected and screened for SCN1A mutations by MLPA, ARMS, and PCR-RFLP confirmed by direct sequencing.

RESULTS

MLPA analysis showed normal patterns, but direct sequencing revealed that generally 20/34 (0.588) probands have common reported single nucleotide polymorphisms (SNPs) (p.A1067G; rs2298771) with allelic frequency as 0.706/0.294 in patients and 0.515/0.485 in control group, respectively, for A/G. No significant differences between groups were observed. Moreover, four novel allelic variants as missense substitutions included two new sequence variation (p.F412 I, p.Y1274N) and two previously reported mutations (p.R101G, p.S103G) that were detected in 4/34 probands but not in control groups and other healthy normal family members.

CONCLUSIONS

Clinical diagnosis could nearly establish the classification, but mutation screening helps clinicians to confirm their data. We found mutation in four probands and confirmed the net diagnosis. Our data suggest that the clinical symptom variations could be also explained, considering the role of modifier genes such as mitochondrial mutations or other genes responsible for drug metabolism pathways including multiple drug resistance family genes (ABCB1) or MTHFR.

Neurocognitive effects of phenobarbital discontinuation in epileptic children

PURPOSE

Phenobarbital (PB) is the most widely used antiepileptic drug in the world, but its possible deleterious cognitive and behavioral side effects remain an important concern among physicians and patients.We therefore investigated whether discontinuation of PB in children with epilepsy is accompanied by improvement in cognitive function.

METHODS

Neuropsychiatric performance was evaluated with the Wechsler Intelligence Scale for Children-Revised (WISC-R), in two consecutive 7-month periods, in two groups of children with epilepsy 6-12 years old who had been seizure-free for at least 2 years and whose only antiepileptic drug was PB. The case group comprised 24 patients who discontinued PB, and the control group was comprised of the 21 children who continued to take PB.

RESULTS

Discontinuation of PB improved Total IQ in the case group compared to the control group (P = 0.027). This increase was mostly in performance (nonverbal) items; verbal items remained almost unchanged.

CONCLUSION

These findings suggest that PB affects cognitive function, and the performance (nonverbal) deficits are diminished after discontinuation of therapy.