High genetic heterogeneity of leukodystrophies in Iranian children: the first report of Iranian Leukodystrophy Registry.

Leukodystrophies (LDs) are a heterogeneous group of progressive neurological disorders and characterized by primary involvement of white matter of the central nervous system (CNS). This is the first report of the Iranian LD Registry database to describe the clinical, radiological, and genomic data of Persian patients with leukodystrophies. From 2016 to 2019, patients suspicious of LDs were examined followed by a brain magnetic resonance imaging (MRI). A single gene testing or whole-exome sequencing (WES) was used depending on the neuroradiologic phenotypes. In a few cases, the diagnosis was made by metabolic studies. Based on the MRI pattern, diagnosed patients were divided into cohorts A (hypomyelinating LDs) versus cohort B (Other LDs). The most recent LD classification was utilized for classification of diagnosed patients. For novel variants, in silico analyses were performed to verify their pathogenicity. Out of 680 registered patients, 342 completed the diagnostic evaluations. In total, 245 patients met a diagnosis which in turn 24.5% were categorized in cohort A and the remaining in cohort B. Genetic tests revealed causal variants in 228 patients consisting of 213 variants in 110 genes with 78 novel variants. WES and single gene testing identified a causal variant in 65.5% and 34.5% cases, respectively. The total diagnostic rate of WES was 60.7%. Lysosomal disorders (27.3%; GM2-gangliosidosis-9.8%, MLD-6.1%, KD-4.5%), amino and organic acid disorders (17.15%; Canavan disease-4.5%, L-2-HGA-3.6%), mitochondrial leukodystrophies (12.6%), ion and water homeostasis disorders (7.3%; MLC-4.5%), peroxisomal disorders (6.5%; X-ALD-3.6%), and myelin protein disorders (3.6%; PMLD-3.6%) were the most commonly diagnosed disorders. Thirty-seven percent of cases had a pathogenic variant in nine genes (ARSA, HEXA, ASPA, MLC1, GALC, GJC2, ABCD1, L2HGDH, GCDH). This study highlights the most common types as well as the genetic heterogeneity of LDs in Iranian children.

Phenotype and genotype heterogeneity of PLA2G6-associated neurodegeneration in a cohort of pediatric and adult patients.

BACKGROUND: Phospholipase-associated neurodegeneration (PLAN) caused by mutations in the PLA2G6 gene is a rare neurodegenerative disorder that presents with four sub-groups. Infantile neuroaxonal dystrophy (INAD) and PLA2G6-related dystonia-parkinsonism are the main two subtypes. In this cohort, we reviewed clinical, imaging, and genetic features of 25 adult and pediatric patients harboring variants in the PLA2G6. METHODS: An extensive review of the patients' data was carried out. Infantile Neuroaxonal Dystrophy Rating Scale (INAD-RS) was used for evaluating the severity and progression of INAD patients. Whole-exome sequencing was used to determine the disease's underlying etiology followed by co-segregation analysis using Sanger sequencing. In silico prediction analysis based on the ACMG recommendation was used to assess the pathogenicity of genetic variants. We aimed to survey a genotype-genotype correlation in PLA2G6 considering all reported disease-causing variants in addition to our patients using the HGMD database and the chi-square statistical approach. RESULTS: Eighteen cases of INAD and 7 cases of late-onset PLAN were enrolled. Among 18 patients with INAD, gross motor regression was the most common presenting symptom. Considering the INAD-RS total score, the mean rate of progression was 0.58 points per month of symptoms (Standard error 0.22, lower 95% - 1.10, and upper 95% - 0.15). Sixty percent of the maximum potential loss in the INAD-RS had occurred within 60 months of symptom onset in INAD patients. Among seven adult cases of PLAN, hypokinesia, tremor, ataxic gate, and cognitive impairment were the most frequent clinical features. Various brain imaging abnormalities were also observed in 26 imaging series of these patients with cerebellar atrophy being the most common finding in more than 50%. Twenty unique variants in 25 patients with PLAN were detected including nine novel variants. Altogether, 107 distinct disease-causing variants from 87 patient were analyzed to establish a genotype-phenotype correlation. The P value of the chi-square test did not indicate a significant relationship between age of disease onset and the distribution of reported variants on PLA2G6. CONCLUSION: PLAN presents with a wide spectrum of clinical symptoms from infancy to adulthood. PLAN should be considered in adult patients with parkinsonism or cognition decline. Based on the current knowledge, it is not possible to foresee the age of disease onset based on the identified genotype.

Novel phenotype and genotype spectrum of WDR62 in two patients with associated primary autosomal recessive microcephaly.

BACKGROUND: Microcephaly is a prominent feature of patients with primary autosomal recessive microcephaly 2 (MCPH2) caused by mutations in the WD Repeat Domain 62 (WDR62; OMIM: 613,583). AIM: The study aimed to identify the underlying genetic factor(s) causing microcephaly in two patients in a consanguineous Iranian family. METHODS: Two male patients (11 and 27 years old) were noticed due to microcephaly, neurodevelopmental delay, and occasional seizures. The younger patient (the proband) was subjected to paired-end whole-exome sequencing followed by Sanger sequencing to detect any underlying genetic factor. RESULTS: Upon examination, both patients showed microcephaly as a prominent manifestation; they were under-weighted as well. The patients had a moderate gross motor impairment, severe cognitive disability and speech delay, increased deep tendon reflexes, flexible joint contractures, sensorineural hearing loss, and vertical nystagmus as a new ocular finding. The proband had more severe neurodevelopmental delay symptoms. The brain magnetic resonance imaging series revealed severe structural and cortical brain abnormalities in addition to hemiatrophy. Using Whole-exome Sequencing, a novel homozygous missense variant-NM_001083961.2; c.1598A > G: p.(His533Arg)-was identified in the WDR62. Subsequently, in silico analyses determined the possible impacts of the novel variant on the structure and function of WDR62 protein. CONCLUSIONS: Herein, we identified a novel homozygous missense variant in the WDR62 in two patients with MCPH2. Vertical nystagmus and sensorineural hearing loss were detected as novel neurological findings. The present study expands the phenotype and genotype spectrum of MCPH2.

A Homozygote Mutation in S-Antigen Visual Arrestin SAG Gene in an Iranian Patient with Oguchi Type One: A Case Report.

Oguchi disease is a rare autosomal recessive form of congenital stationary night blindness (CSNB) characterized by specific features such as golden-brown discoloration of the fundus called Mizuo-Nakamura phenomenon which is distinguishable by fundoscopy, and retinography. Clinical diagnosis is confirmed through genetic test. Two known genes in pathogenesis of Oguchi disease are SAG and GRK1. A 35-year-old Iranian male exhibiting the clinical features of congenital stationary night blindness, was referred to the genetic clinic of Dr. Farhud, Tehran, Iran in 2012 and examined. Ophthalmic examination including slit-lamp biomicroscopy, perimetry and funduscopy was performed. Additionally, the full-field electroretinography and molecular testing for congenital stationary night blindness were performed. Molecular genetic tests, including the analysis of GSK1 and SAG genes exon-intron boundaries were performed for this patient and his family. According to the sequencing results, we did not find any mutation in GSK1 gene. However, a new homozygote mutation at location chr2:233320735, c.517delC, p.P96LfsX28 was identified in exon four of SAG gene. This deletion causes a frame shift mutation, and premature stop codon that results in deletion of about 281 amino acid residues of S-antigen visual arrestin protein (from entire C-terminal). This mutation was also found in patient's parents and one of his sister as heterozygote form. This is the first molecular evidence for SAG gene mutation in an Iranian family affected with Oguchi disease type 1. The identification of the new c.517delC, p.P96LfsX28 mutation in this family with Oguchi disease can confirm the pathogenicity of this variant.

Novel imaging and clinical phenotypes of CONDSIAS disorder caused by a homozygous frameshift variant of ADPRHL2: a case report.

BACKGROUND: Stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS) is an autosomal recessive disorder caused by defects in the ADP-Ribosylhydrolase Like 2 (ADPRHL2; OMIM: 618170) gene. This gene encodes the ADP-ribosylhydrolase enzyme (ARH3) that eliminates the addition of poly-ADP ribose (PAR) in the cellular stress onto proteins in the ADP-ribosylation process in which adding one or more ADP-ribose moieties onto the target proteins in the post-translational modification have occurred. In this study, we report a new case of CONDSIAS in the Iranian population. A literature review of CONDSIAS is also included. CASE PRESENTATION: A four-year-old female patient, born to a consanguineous Iranian family, was referred with various clinical symptoms including impaired speech, variable ataxia, infrequent seizures, and gradual onset of truncal hypotonia. Over time, she developed complete motor and speech regression, bilateral sensorineural hearing loss, infrequent seizures, abdominal distension and gastrointestinal (GI) intolerance, and loss of consciousness. To better molecularly diagnose, trio-whole-exome sequencing (WES) was performed on the proband and her parents. Sanger sequencing was also applied to investigate co-segregation analysis. Using in silico predictive tools, the possible impacts of the variant on the structure and function of ADPRHL2 protein were predicted. All basic metabolic tests were normal, while serial coronal magnetic resonance imaging (MRI) showed progressive cerebral and cerebellar atrophy in addition to cerebral white matter signal changes as a novel neuroimaging finding. GI intolerance was another novelty of clinical scenarios in the patient. An auditory brainstem response test showed a severe bilateral sensorineural hearing loss. An electroencephalogram also confirmed focal seizures. From the molecular perspective, a novel homozygous frameshift variant in the ADPRHL2 gene (NM_017825.2; c.636_639del, p.(Leu212fs)) was identified by WES. CONCLUSIONS: CONDSIAS is an ultra-rare neurodegenerative disorder. In the present study, we introduced extra-neurological and neuroimaging findings of this disorder in a female child caused by a novel frameshift variation in the ADPRHL2 gene.

Association of Htra1 gene polymorphisms with the risk of developing AMD in Iranian population.

BACKGROUND: Half of the cases of vision loss in people under 60 years of age have been attributed to age-related macular degeneration (AMD). This is a multifactorial disease with late onset. It has been demonstrated that many different genetic loci are implicated in the risk of developing AMD in different populations. In the current study, we investigated the association of high-temperature requirement A-1 (HTRA1) gene polymorphisms with the risk of developing AMD in the Iranian population. METHODS: Genomic DNA samples were extracted from 120 patients with AMD and 120 healthy age- and sex-matched controls. A 385 base-pair fragment of the HTRA1 gene promoter region was amplified using the polymerase chain reaction (PCR) technique and sequenced. The frequencies of the alleles were calculated and statistical analysis was performed using SPSS software. RESULTS: Our study demonstrated that the rate of polymorphisms rs11200638 -625 G>A and rs2672598 -487T>C were significantly greater in AMD patients than in healthy controls from the Iranian population. CONCLUSIONS: The results of our study indicate that HTRA1 gene promoter region polymorphisms are associated with the risk of developing AMD in the Iranian population.

Complement Factor H Y402H and LOC387715 A69S Polymorphisms in Association with Age-Related Macular Degeneration in Iran.

PURPOSE: To determine the frequency of complement factor H (Y402H) and age related macular degeneration susceptibility gene 2 (A69S) single nucleotide polymorphisms in patients with age-related macular degeneration (AMD) and in matched non-AMD controls in an Iranian population. METHODS: Seventy patients with AMD and 86 age- and sex-matched controls were recruited and examined. Peripheral blood sample was obtained from all subjects for DNA extraction and direct sequencing of Y402H and A69S genes. Odds ratios (ORs) with 95% confidence intervals (CIs) for the association of Y402H and A69S polymorphisms with AMD were determined. RESULTS: The frequencies of both homozygous and heterozygous genotypes were significantly higher in cases than controls for both Y402H and A69S polymorphisms. In comparison to the wild genotypes, OR for AMD associated with Y402H and A69S polymorphisms were 1.9 (95% CI, 1.1-3.2) and 2.2 (95%CI, 1.6-3.1), respectively. Joint risk analysis considering both genes revealed a higher risk of AMD when polymorphisms were present for both genes. CONCLUSION: Y402H and A69S polymorphisms were strongly associated with AMD in this Iranian population.

Genetic polymorphisms in calcitonin receptor gene and risk for recurrent kidney calcium stone disease.

INTRODUCTION: In this study the full sequence of the calcitonin receptor gene (CALCR) in a group of Iranian males suffering from recurrent calcium urinary stones was compared with that of a control group. METHODS: Serum and urinary biochemistry related to urolithiasis were evaluated in 105 males diagnosed with recurrent kidney calcium stones and 101 age-matched healthy control males. The polymerase chain reaction single-strand conformation polymorphism method was used to detect new polymorphisms in the CALCR. RESULTS: Nine polymorphisms were detected; seven were in the non-coding and two in the coding region. The T allele associated with the 3'UTR+18C>T polymorphism was observed exclusively in the stone formers. The exact odds ratio for the T allele in this locus for those at risk of stone formation was 36.72 (95% CI 4.95-272.0) (p < 0.001). The mean (standard deviation) urine calcium concentration was 117 (60) mg/l in patients with the C allele and 152 (72) mg/l in those with the T allele (p = 0.03). In addition, IVS1-6T>C and IVS1insA polymorphisms in intron 1 were associated with kidney stone disease (p < 0.001). Regarding single nucleotide polymorphism 447, mean (standard deviation) of serum calcitonin levels were 16.7 (18.7) pg/ml, 10.5 (11.0) pg/ml and 9.94 (9.7) pg/ml in subjects with TT, TC and CC genotypes, respectively (p = 0.01). CONCLUSION: Our data indicate a potential association between 3'UTR+18C>T and intron 1 polymorphisms in the CALCR and the risk of kidney stone disease.

The effect of TGF-beta2 on MMP-2 production and activity in highly metastatic human bladder carcinoma cell line 5637.

Transforming growth factor-beta (TGF-beta) superfamily regulates matrix metalloproteinases (MMP), which intrinsically regulate various cell behaviors leading to metastasis. We investigated the effect of TGF-beta(2) on MMP-2 regulation in human bladder carcinoma cell line 5637. Zymography, ELISA, and real-time polymerase chain reaction revealed that TGF-beta(2) stimulated MMP-2 production, but the transcription of its gene remained unchanged. Wortmannin could not inhibit MMP-2 secretion and activity and conversely the amount of the protein and its enzymatic activity were increased. These data suggest that TGF-beta(2) increased MMP-2 at the posttranscriptional level and this upregulation was independent of phosphatidylinositol 3-kinase signaling pathway.