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Background: Ion channel dysfunction in the brain can lead to impairment of neuronal membranes and generate several neurological diseases, especially neurodevelopmental disorders. Methods: In this study, we set out to delineate the genotype and phenotype spectrums of 14 Iranian patients from 7 families with intellectual disability (ID) and/or developmental delay (DD) in whom genetic mutations were identified by next-generation sequencing (NGS) in 7 channel-encoding genes: KCNJ10, KCNQ3, KCNK6, CACNA1C, CACNA1G, SCN8A, and GRIN2B. Moreover, the data of 340 previously fully reported ID and/or DD cases with a mutation in any of these seven genes were combined with our patients to clarify the genotype and phenotype spectrum in this group. Results: In total, the most common phenotypes in 354 cases with ID/DD in whom mutation in any of these 7 channel-encoding genes was identified were as follows: ID (77.4%), seizure (69.8%), DD (59.8%), behavioral abnormality (29.9%), hypotonia (21.7%), speech disorder (21.5%), gait disturbance (20.9%), and ataxia (20.3%). Electroencephalography abnormality (33.9%) was the major brain imaging abnormality. Conclusion: The results of this study broaden the molecular spectrum of channel pathogenic variants associated with different clinical presentations in individuals with ID and/or DD.

Background Neurodevelopmental and intellectual impairments are extremely heterogeneous disorders caused by a diverse variety of genes involved in different molecular pathways and networks. Genetic alterations in cilia, highly-conserved organelles with sensorineural and signal transduction roles can compromise their proper functions and lead to so-called "ciliopathies" featuring intellectual disability (ID) or neurodevelopmental disorders as frequent clinical manifestations. Here, we report several Iranian families affected with ID and other ciliopathy-associated features carrying known and novel variants in two ciliary genes; CEP104 and CEP290. Methods Whole exome and Targeted exome sequencing were carried out on affected individuals. Lymphoblastoid cell lines (LCLs) derived from the members of affected families were established for two families carrying CEP104 mutations. RNA and protein expression studies were carried out on these cells using qPCR and Western blot, respectively. Results A novel homozygous variant; NM_025114.3:c.7341_7344dupACTT p.(Ser2449Thrfs*8) and four previously reported homozygous variants; NM_025114.3:c.322C>T p.(Arg108*), NM_025114.3:c.4393C>T p.(Arg1465*), NM_025114.3:c.5668G>T p.(Gly1890*) and NM_025114.3:c.1666dupA p.(Ile556Asnfs*20) were identified in CEP290. In two other families, two novel homozygous variants; NM_014704:c.2356_2357insTT p.(Cys786Phefs*11) and NM_014704:c.1901_1902insT p.(Leu634Phefs*33) were identified in CEP104, another ciliary gene. qPCR and Western blot analyses showed significantly lower levels of CEP104 transcripts and protein in patients compared to heterozygous or normal family members. Conclusion We emphasize on the clinical variability and pleiotropic phenotypes due to variants of these genes. In conclusion, our findings support the pivotal role of these genes resulting in cognitive and neurodevelopmental features.

Mutations in adaptor protein complex‐4 (AP‐4) genes have first been identified in 2009, causing a phenotype termed as AP‐4 deficiency syndrome. Since then several patients with overlapping phenotypes, comprised of intellectual disability (ID) and spastic tetraplegia have been reported. To delineate the genotype‐phenotype correlation of the AP‐4 deficiency syndrome, we add the data from 30 affected individuals from 12 out of 640 Iranian families with ID in whom we detected disease‐causing variants in AP‐4 complex subunits, using next‐generation sequencing. Furthermore, by comparing genotype‐phenotype findings of those affected individuals with previously reported patients, we further refine the genotype‐phenotype correlation in this syndrome. The most frequent reported clinical findings in the 101 cases consist of ID and/or global developmental delay (97%), speech disorders (92.1%), inability to walk (90.1%), spasticity (77.2%), and microcephaly (75.2%). Spastic tetraplegia has been reported in 72.3% of the investigated patients. The major brain imaging findings are abnormal corpus callosum morphology (63.4%) followed by ventriculomegaly (44.5%). Our result might suggest the AP‐4 deficiency syndrome as a major differential diagnostic for unknown hereditary neurodegenerative disorders.

Neurodevelopmental delay and intellectual disability (ID) can arise from numerous genetic defects. To date, variants in the EXOSC gene family have been associated with such disorders. Using next-generation sequencing (NGS), known and novel variants in this gene family causing autosomal recessive ID (ARID) have been identified in five Iranian families. By collecting clinical information on these families and comparing their phenotypes with previously reported patients, we further describe the clinical variability of ARID resulting from alterations in the EXOSC gene family, and emphasize the role of RNA processing dysregulation in ARID.

Neuromuscular diseases (NMDs) include a broad range of disorders affecting muscles, nerves and neuromuscular junctions. Their overlapping phenotypes and heterogeneous genetic nature have created challenges in diagnosis which calls for the implementation of massive parallel sequencing as a candidate strategy to increase the diagnostic yield. In this study, total of 45 patients, mostly offspring of consanguineous marriages were examined using whole exome sequencing. Data analysis was performed to identify the most probable pathogenic rare variants in known NMD genes which led to identification of causal variants for 33 out of 45 patients (73.3%) in the following known genes: CAPN3, Col6A1, Col6A3, DMD, DYSF, FHL1, GJB1, ISPD, LAMA2, LMNA, PLEC1, RYR1, SGCA, SGCB, SYNE1, TNNT1 and 22 novel pathogenic variants were detected. Today, the advantage of whole exome sequencing in clinical diagnostic strategies of heterogeneous disorders is clear. In this cohort, a diagnostic yield of 73.3% was achieved which is quite high compared to the overall reported diagnostic yield of 25% to 50%. This could be explained by the consanguineous background of these patients and is another strong advantage of offering clinical exome sequencing in diagnostic laboratories, especially in populations with high rate of consanguinity.

The calcium channel, voltage-dependent, L-type, alpha 1S subunit (CACNA1S) gene encodes a skeletal Ca2+ channel which is involved in calcium-dependent processes such as muscle contraction and neurotransmitter release. Mutations in this gene have been accompanied by hypo- and normokalemic periodic paralysis, thyrotoxic periodic paralysis, and susceptibility to malignant hyperthermia. We report the clinical and genetic findings in a patient diagnosed with metabolic myopathy who had episodic attacks of muscle pain and weakness but with no family background of the disease. Next-generation sequencing (NGS) using a panel targeting metabolic myopathy and myotonia genes identified a de novo heterozygous pathogenic variant c.3724AG, p.Arg1242Gly, in exon 30 of CACNA1S. As the second report of this variant, this case may broaden the CACNA1S-related disease spectrum to include normokalemic periodic paralysis.

Fanconi anemia (FA) is a rare genetic syndrome characterized by developmental defects, bone marrow failure, and a high cancer risk. FA is usually inherited as an autosomal recessive condition. This disease is genetically heterogeneous and mutations in 16 different genes have been identified in FA patients to date. An accurate diagnosis needs detection of pathogenic variations in the FA genes along with positive results from chromosome breakage test.In this study, 48 families with at least 2 affected FA patients and positive chromosome breakage test were enrolled from the Iranian population. Molecular analysis of FA genes was performed using Next Generation Sequencing (NGS) method and Multiple Ligation Dependent Probe Amplification (MLPA).Causal mutations for 30 (63%) patients were identified in homozygous or compound heterozygous forms. FANCA had the highest mutation frequency rate (83%) followed by FANCG (10%), FANCD2 (3%) and FANCL (3%). A significant proportion (44%) of FANCA mutations were large rearrangements.Genetic testing for FA patients improves the accuracy of diagnosis and also will be essential for genetic counselling and prenatal diagnosis for future pregnancies in the family. Availability of NGS technology has made the screening of all known FA genes at once more practical and affordable.

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.

significant repigmentation in vitiligo was reported with tofacitinib citrate treatment (Craiglow et al., 2015). A case of reversal of alopecia areata has been observed with baricitinib treatment (Jabbari et al., 2015). In summary, we demonstrate a substantial benefit from ruxolitinib therapy in a case of chilblain LE.Our observation supports the idea that JAK/STAT inhibition provides a promising therapeutic approach for the treatment of cutaneous autoimmune diseases, particularly LE.

Calpain3 is a calcium-dependent intracellular protease involved in an autosomal recessive form of muscular dystrophy known as limb-girdle muscular dystrophy type 2A. Many pathogenic mutations have been identified in calpain3, encoded by the CAPN3 gene, which leads to weakness of the pelvic and shoulder girdle muscles. In the present study, whole exome sequencing was performed on six unrelated Iranian families who presented with progressive muscle weakness, with a strong suspicion of Calpainopathies. Genetic analysis of CAPN3 gene revealed five causative variants which had not been reported in the Iranian population before including a novel 6 bp deletion (c.795_800delCATTGA) and four previously reported mutations (c.1939G > T, c.2243G > A, c.2257delGinsAA, and c.2380 + 2T > G). Our findings indicate that exome sequencing can be a very effective and affordable method to diagnose heterogeneous muscular dystrophies, especially in consanguineous populations such as Iran.

Mutations in plectin, a widely expressed giant cytolinker protein can lead to different diseases mostly with signs of muscular dystrophy (MD) and skin blistering. The only report of plectin-related disease without skin involvement is limb-girdle muscular dystrophy type 2Q (LGMD2Q) phenotype, showing early-onset limb-girdle muscular dystrophy symptoms with progressive manner and no cranial muscle involvement. Here, we report a non-consanguineous Iranian family with two affected sisters showing progressive limb and ocular muscle weakness. Whole Exome Sequencing (WES) led to identification of a compound heterozygous mutations, p.Gln1022Ter (c.3064CT) and p.Gly3835Ser (c.11503GA), in PLEC gene. To the best of our knowledge, this would be the first report of a patient with LGMD and myasthenic symptoms without any skin involvement, caused by plectinopathy. This observation extends the phenotypic spectrum of PLEC related diseases and suggests a variable expression of the PLEC- related symptoms.

Background:Hearing defects are the most common sensory disorders, affecting 1 out of every 500 newborns. ATP6V1B mutations are associated with early sensorineural hearing loss, whereas ATP6V0A4 mutations are classically associated with either late-onset sensorineural hearing loss or normal hearing. ATP6V1B1 and ATP6V0A4 genetic mutations cause recessive forms of distal renal tubular acidosis.Method:Ten unrelated deaf Iranian families with distal renal tubular acidosis were referred to the Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran. All exons of the ATP6V1B1 and ATP6V0A4 genes were sequenced in affected family members.Results:We identified a previously reported ATP6V1B1 frameshift mutation (P385fsX441) in two families and a nucleotide substitution in exon 10 (P346R) in three families. In addition, one patient was homozygous for a novel nucleotide substitution in exon 3.Conclusion:ATP6V1B1 genetic mutations were detected in more than half of the families studied. Mutations in this gene therefore seem to be the most common causative factors in hearing loss associated with distal renal tubular acidosis in these families.

Background: Diagnosis of hereditary hearing loss (HHL) as a heterogeneous disorder is very important especially in countries with high rates of consanguinity where the autosomal recessive pattern of inheritance is prevalent. Techniques such as next-generation sequencing, a comprehensive genetic test using targeted genomic enrichment and massively parallel sequencing (TGE + MPS), have made the diagnosis more cost-effective. The aim of this study was to determine HHL variants with comprehensive genetic testing in our country. of this study was to determine HHL variants with comprehensive genetic testing in our country. Methods: Fifty GJB2 negative individuals with HHL were referred to the Kariminejad-Najmabadi Pathology and Genetics Center, Tehran, one of the reference diagnostic genetic laboratories in Iran, during a 3-year period between 2014 and 2017. They were screened with the OtoSCOPE test, the targeted genomic enrichment and massively parallel sequencing (TGE + MPS) platform after a detailed history had been taken along with clinical evaluation. Results: Among 32 out of 50 GJB2 negative patients (64%), 34 known pathogenic and novel variants were detected of which 16 (47%) were novel, identified in 10 genes of which the most prevalent were CDH23, MYO7A and MYO15A. Conclusion: These results provide a foundation from which to make appropriate recommendations for the use of comprehensive genetic testing in the evaluation of Iranian patients with hereditary hearing loss.