OTX2 mutations contribute to the otocephaly-dysgnathia complex

BACKGROUND

Otocephaly or dysgnathia complex is characterised by mandibular hypoplasia/agenesis, ear anomalies, microstomia, and microglossia; the molecular basis of this developmental defect is largely unknown in humans.

METHODS AND RESULTS

This study reports a large family in which two cousins with micro/anophthalmia each gave birth to at least one child with otocephaly, suggesting a genetic relationship between anophthalmia and otocephaly. OTX2, a known microphthalmia locus, was screened in this family and a frameshifting mutation was found. The study subsequently identified in one unrelated otocephalic patient a sporadic OTX2 mutation. Because OTX2 mutations may not be sufficient to cause otocephaly, the study assayed the potential of otx2 to modify craniofacial phenotypes in the context of known otocephaly gene suppression in vivo. It was found that otx2 can interact genetically with pgap1, prrx1, and msx1 to exacerbate mandibular and midline defects during zebrafish development. However, sequencing of these loci in the OTX2-positive families did not unearth likely pathogenic lesions, suggesting further genetic heterogeneity and complexity.

CONCLUSION

Identification of OTX2 involvement in otocephaly/dysgnathia in humans, even if loss of function mutations at this locus does not sufficiently explain the complex anatomical defects of these patients, suggests the requirement for a second genetic hit. Consistent with this notion, trans suppression of otx2 and other developmentally related genes recapitulate aspects of the otocephaly phenotype in zebrafish. This study highlights the combined utility of genetics and functional approaches to dissect both the regulatory pathways that govern craniofacial development and the genetics of this disease group.

Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

INTRODUCTION

Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN).

METHODS

The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period.

RESULTS

In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05).

CONCLUSIONS

This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

Combined genetic mutations have remarkable effect on deep venous thrombosis and/or pulmonary embolism occurence

PURPOSE

Although deep vein thrombosis and thromboembolic diseases differ among various races, they are still important in our day. The difficulties in treatment and following-up of these diseases are caused by secret genetic mutations rather than predisposing factors.

METHODS

Between January 2011 and May 2013, patients who were traced for deep vein thrombosis and/or pulmonary embolism were evaluated retrospectively. 84 patients (53.6% males and 46.4% females) were included in the study. Their family histories, predisposing factors and treatments were researched. Factor V Leiden (G 1691A), Factor II G20210A, Plasminogen Activator Inhibitor-Type 1 (4G/5G), and Methylene Tetrahydrofolate Reductase (C677T, A1298C) mutations were investigated from peripheral venous blood.

RESULTS

Among the genetic mutations we searched, the incidence of single mutation rate was observed at 11.9%, double mutation collocation at 44%, triple mutation collocation at 29.8%, quadruple mutation collocation at 13.1%, and finally, quintuplet mutation collocation at 1.2%. Our approximate mutation number was found as 2.47 ± 0.91.

CONCLUSION

We observed that multiple mutations were high in number compared to single genetic mutations. The patients who have multiple mutations should be more in the front line considering their diagnosis, treatment and following up, and also in terms of decreasing mortality, morbidity and recurrence.

The effects of oral carvacrol treatment against H2O2 induced injury on isolated pancreas islet cells of rats

Pancreatic islet transplantation is an alternative treatment of insulin replacement therapy in diabetes mellitus, but the islets are exposed to many chemical, mechanical damages, and oxidative stress before transplantation. Carvacrol is a well-known essential oil for its antioxidant, antimicrobial, antifungal and antiinflammatory properties. The aim of this study was to investigate the possible protective effects of carvacrol against H 2O 2 induced cellular injury on isolated pancreas islets. After carvacrol (20, 40 and 80 mg/kg/day) treatment, the pancreas islets were isolated by enzyme digestion. The isolated islets were incubated within 0, 150 and 300 µM H 2O 2 containing medium at +4°C for 15 min. Then, the islets were examined with fluorescein diacetate and propidium iodide mixture stains for viability. A number of islets were stored for lipid peroxidation, protein oxidation and DNA fragmentation analysis. The cell viability ratio of Carvacrol 20 mg/kg/day group was increased in comparison to control and vehicle (DMSO) groups. Additionally, carvacrol application protected the cells from lipid peroxidation and protein oxidation induced by H 2O 2. H 2O 2 caused tissue injury and DNA fragmentation. There was only one DNA fragmentation band from islet cells of 20 mg/kg/day carvacrol treated group, however there were more than one bands from control and DMSO groups. In conclusion, carvacrol treatment ameliorates islet cell injury induced by H 2O 2. However, the dose of carvacrol is important and our results suggest that 20 mg/kg/day dose is more effective than doses of 40 or 80 mg/kg/day.

Primary hypogonadism, partial alopecia, and Mullerian hypoplasia: report of a third family and review

Two sisters presented with partial alopecia, primary hypergonadotropic hypogonadism and Mullerian hypoplasia associated with mild mental retardation, microcephaly, flat occiput, sparse eyebrows, absence of breast tissue, absent ovaries, mild-moderate dorsal kyphosis, thin upper lip and unilateral sensorioneural deafness in one of them. They were the product of a Turkish consanguineous marriage. The clinical course for our patients is similar to two families reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622] and Megarbane et al. [Megarbane et al. (2003) Am J Med Genet Part A 119A:214-217]. This report supports the literature by proposing an autosomal recessive syndrome which was firstly reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622]. This condition may be due to a founder mutation.

Assisted reproductive treatment applications in men with normal phenotype but 45,X/46,XY mosaic karyotype: clinical and genetic perspectives

OBJECTIVE

The 45,X/46,XY mosaic karyotype is expressed by a spectrum of genital phenotypes, ranging from normal males through to ambiguous genitalia and to normal females.

CASE REPORTS

We present three cases of men with azoospermia or severe oligozoospermia, and a 45,X/46,XY mosaic karyotype and two with a Y-chromosome microdeletion. Phenotypically, they appeared as normal males, with normal penis, scrotum and secondary sex characteristics. Testicular sperm extraction and aspiration were applied to patients, and couples were prepared for assisted reproductive therapy. All men with azoospermia or severe oligozoospermia were evaluated for karyotype and Y-chromosome microdeletion even if they had normal phenotypes.

CONCLUSION

Possibilities for finding sperm and the biologic paternity in subjects with 45,X/46,XY karyotype should be considered. Furthermore, the increased risk for testicular neoplasia with mosaic karyotypes should be taken into consideration.

The protective effect of erdosteine on radiocontrast induced nephrotoxicity in rats

Acute renal failure resulting from radiocontrast-induced nephrotoxicity (RIN) is suggested to occur via medullary ischemia coupled with the generation of free radicals and oxidative injury to tubular cells. The aim of the present study was to assess the effects of erdosteine on prevention of RIN. Thirty-three Wistar-albino rats were divided into five groups: control (group 1, n = 6), radiocontrast media (group 2, n = 6), erdosteine (group 3, n = 7), erdosteine four doses before radiocontrast application (group 4, n = 7) and erdosteine one dose at the same day with radiocontrast application (group 5, n = 7). RIN was induced by administration of intravenous high osmolar contrast media amidotrizoate (6 mL/kg). Total RNA was extracted from the kidney, and the expression levels of Lipocalin 2 (Lcn2) and secreted phosphoprotein 1 (Spp1) genes were evaluated by real time reverse transcription polymerase chain reaction (real-time RT-PCR). Total antioxidant status (TAS) and total oxidant status (TOS) were measured in kidney homogenates and serum samples. Serum creatinine, BUN (Blood Urea Nitrogen) and cystatin-C levels were measured from serum samples. The kidneys were evaluated histopathologically. The expression levels of Spp1 and Lcn2 genes in group 2 were significantly higher than groups 1, 3, 4, and 5. The expression levels of Spp1 and Lcn2 genes in group 4 were four and two times lower than group 5, respectively. Kidney TOS levels in group 2 were significantly higher than groups 1, 3, 4, and 5. Kidney TAS levels in group 3 were higher than group 2. Kidney oxidative stress index (OSI) levels in group 2 were significantly higher than groups 4 and 5. All rats in contrast media group developed tubular necrosis, proteinaceous casts, medullary congestion although these changes were significantly reduced in groups 4 and 5. This study demonstrated that multiple doses of erdosteine before application may have higher protective effects against RIN.

Genotoxic effect of albendazole in pediatric patients with hepatic hydatid disease

OBJECTIVE

Hydatid disease occurs throughout the world and is treated with both surgery and medical administration of albendazole. Some adverse effects of albendazole are known. However, its genotoxic effect on humans has not been reported yet. In this study, we aimed to investigate the genotoxic effect of albendazole on human lymphocytes in vivo.

METHODS

The study involved 14 children (eight males and six females) who had undergone operations for hepatic hydatid disease. The ages of the patients ranged from 6 to 13 years. Genotoxicity of albendazole was evaluated as the frequency of sister chromatid exchange (SCE) and micronucleated cells in the patient's lymphocytes. Prior to and after albendazole treatment, blood samples were obtained from these patients for SCE and micronucleus (MN) studies. SCE and MN frequencies of the patients were measured separately before and after albendazole treatment.

RESULTS

All patient SCE values increased significantly after albendazole administration (p<0.001). Similarly, MN frequencies in all the patients increased significantly following albendazole treatment (p<0.001).

CONCLUSION

This study revealed that both SCE and MN frequencies are higher after albendazole treatment. The results suggest that albendazole may be genotoxic to human lymphocytes in vivo.

A retrospective analysis of amniocenteses performed for advanced maternal age and various other indications in Turkish women

OBJECTIVE

Prenatal cytogenetic diagnostic methods for the diagnosis of fetal chromosomal anomalies have been used reliably over the last 40 years. Advanced maternal age has become a basic indication for amniocentesis.

METHODS

We examined the results of the chromosome analyses of 3485 women that had amniocentesis for any reason during their antenatal care in our perinatology clinic in 2007-2009. Amniocentesis was performed for advanced maternal age in 1456 women (41.8%) and for other reasons in the remaining 2029 women (58.2%). Chromosomal anomalies were examined numerically and structurally.

RESULTS

When the amniocentesis results of the patients were reviewed as numerically normal or abnormal; 40 (2.7%) of 1456 amniocentesis procedures performed for advanced maternal age, 5 (0.9%) of 531 procedures performed for an increased double-test risk and 14 (1.3%) of 1095 procedures performed for an increased triple test risk were found to have chromosomal aneuploidy.

CONCLUSIONS

Maternal age is still the most prevalent indication for genetic amniocentesis other than positive prenatal screening tests. Among women with advanced maternal age, prenatal ultrasonography for soft markers of chromosomal aneuploidy accompanied with maternal serum biochemical screening tests should be evaluated during the decision making process of genetic amniocentesis.

Association between pre-eclampsia and inherited thrombophilias

OBJECTIVE

The aim was to determine whether inherited thrombophilia increases the risk of pre-eclampsia (PE) or interferes with its clinical course.

MATERIAL AND METHODS

We included 50 patients with severe PE and 50 healthy pregnant women. Patients were evaluated for inherited thrombophilia.

RESULTS

Fourteen patients in the study group was factor V Leiden (FVL) carrier while it was 12% in the control group. In women with PE, FVL and other inherited thrombophilic factors were not more prevalent than in the controls.

CONCLUSION

The present study failed to demonstrate an association between the inherited thrombophilias and PE.

Maturity Onset Diabetes of the Young due to Glucokinase, HNF1-A, HNF1-B, and HNF4-A Mutations in a Cohort of Turkish Children Diagnosed as Type 1 Diabetes Mellitus

BACKGROUND/AIMS

Maturity onset diabetes of the young (MODY) is a rare condition often misdiagnosed as type 1 diabetes (T1D). The purposes of this study were: to identify any patients followed in a large Turkish cohort as T1D, with an atypical natural history, who may in fact have MODY, and to define the criteria which would indicate patients with likely MODY as early as possible after presentation to allow prompt genetic testing.

METHODS

Urinary C-peptide/creatinine ratio (UCPCR) was studied in 152 patients having a diagnosis of T1D for at least 3 years. Those with a UCPCR ≥0.2 nmol/mmol were selected for genetic analysis of the Glucokinase (GCK), Hepatocyte nuclear factor 1a (HNF1A), Hepatocyte nuclear factor 4a (HNF4A), and Hepatocyte nuclear factor 1b (HNF1B) genes. This UCPCR cut-off was used because of the reported high sensitivity and specificity. Cases were also evaluated using a MODY probability calculator.

RESULTS

Twenty-three patients from 152 participants (15.1%) had a UCPCR indicating persistent insulin reserve. The mean age ± SD of the patients was 13.6 ± 3.6 years (range 8.30-21.6). Of these 23, two (8.7%) were found to have a mutation, one with HNF4A and one with HNF1B mutation. No mutations were detected in the GCK or HNF1A genes.

CONCLUSION

In Turkish children with a diagnosis of T1D but who have persistent insulin reserve 3 years after diagnosis, up to 9% may have a genetic mutation indicating a diagnosis of MODY.

Homozygous SQSTM1 nonsense variant identified in a patient with brainstem involvement

In recent years, with advances in molecular genetics, many new mutations with various ataxic syndromes have been identified. Recently, homozygous sequestosome 1 (SQSTM1) gene variant with a progressive childhood-onset cerebellar ataxia, dystonia and gaze palsy was described. Here we describe a patient with progressive cerebellar ataxia and gaze palsy, as well as myoclonus, cognitive impairment and growth retardation with a homozygous SQSTM1 variant NM_003900.5:c.55G > T (p.Glu19*). Our case had brainstem lesions on brain magnetic resonance imaging that have not been previously reported. This novel finding expands the SQSTM1 gene-associated neuroradiologic spectrum. Homozygous SQSTM1 variant should be considered in the differential diagnosis in patients presenting with cerebellar findings, gaze palsy, and cognitive impairment to facilitate early diagnosis and genetic counseling.

Thyroid hormone resistance in two patients with papillary thyroid microcarcinoma and their BRAFV600E mutation status

Resistance to thyroid hormone (RTH) is a rare autosomal dominant hereditary disorder. Here in, we report two patients with RTH in whom differentiated thyroid cancer was diagnosed. Two patients were admitted to our clinic and their laboratory results were elevated thyroid hormone levels with unsuppressed TSH. We considered this situation thyroid hormone resistance in the light of laboratory and clinical datas. Thyroid nodule was palpated on physical examination. Thyroid ultrasonography showed multiple nodules in both lobes. Total thyroidectomy was performed. The pathological findings were consistent with papillary thyroid microcarcinoma. BRAFV600E mutation analysis results were negative. RTH is very rare and might be overlooked. There is no consensus on how to overcome the persistently high TSH in patients with RTH and differentiated thyroid cancer (DTC). Further studies are needed to explain the relationship between RTH and DTC which might be helpful for the treatment of these patients.

TRAPPC9-Related Intellectual Disability: Report of Two New Cases and Review of the Literature

Introduction

Hereditary forms of intellectual disability (ID), an estimated prevalence ranging between 1% and 3% in the general population, are among the most important problems in health care. Especially, autosomal-recessive ID has a very heterogeneous molecular basis and a lack of specific phenotypic features.

Methods

Here, we report on two unrelated patients with autosomal-recessive ID, microcephaly, and autistic features and review the patients with TRAPPC9-related ID. Whole-exome sequencing and array CGH were performed for molecular diagnosis of the patients.

Results

The first case has a microdeletion on chromosome 8q24.23-q24.3 region which is 1.7 Mb in length and includes the last 5 exons of TRAPPC9, and c.3435delG [p.Thr1146Profs*8] deletion. The second case has a homozygous missense c.623A>C (p.His208Pro) variant in TRAPPC9 which is detected by means of whole-exome sequencing study of the proband. We also reviewed the clinical findings and mutation spectrum of all patients with TRAPPC9-related ID reported so far.

Conclusions

Our study showed that the most consistent clinical findings for TRAPPC9-related ID are ID, microcephaly, and some structural brain MRI abnormalities. The mutations in the TRAPPC9 are scattered throughout all exons of TRAPPC9 indicating there is no hot spot mutation region in this gene.

Bi-allelic truncating variants in CASP2 underlie a neurodevelopmental disorder with lissencephaly

Lissencephaly (LIS) is a malformation of cortical development due to deficient neuronal migration and abnormal formation of cerebral convolutions or gyri. Thirty-one LIS-associated genes have been previously described. Recently, biallelic pathogenic variants in CRADD and PIDD1, have associated with LIS impacting the previously established role of the PIDDosome in activating caspase-2. In this report, we describe biallelic truncating variants in CASP2, another subunit of PIDDosome complex. Seven patients from five independent families presenting with a neurodevelopmental phenotype were identified through GeneMatcher-facilitated international collaborations. Exome sequencing analysis was carried out and revealed two distinct novel homozygous (NM_032982.4:c.1156delT (p.Tyr386ThrfsTer25), and c.1174 C > T (p.Gln392Ter)) and compound heterozygous variants (c.[130 C > T];[876 + 1 G > T] p.[Arg44Ter];[?]) in CASP2 segregating within the families in a manner compatible with an autosomal recessive pattern. RNA studies of the c.876 + 1 G > T variant indicated usage of two cryptic splice donor sites, each introducing a premature stop codon. All patients from whom brain MRIs were available had a typical fronto-temporal LIS and pachygyria, remarkably resembling the CRADD and PIDD1-related neuroimaging findings. Other findings included developmental delay, attention deficit hyperactivity disorder, hypotonia, seizure, poor social skills, and autistic traits. In summary, we present patients with CASP2-related ID, anterior-predominant LIS, and pachygyria similar to previously reported patients with CRADD and PIDD1-related disorders, expanding the genetic spectrum of LIS and lending support that each component of the PIDDosome complex is critical for normal development of the human cerebral cortex and brain function.

Association of vitamin D receptor gene FokI and TaqI polymorphisms and risk of RDS

Background: Vitamin D and its receptor (VDR) have important roles in perinatal lung development. The objective of this study was to investigate the possible association between VDR FokI and TaqI polymorphism and development of respiratory distress syndrome (RDS) in preterm infants.Method: A total of 173 premature infants <34 weeks: 82 with RDS and 91 without RDS were enrolled. Genotyping of VDR polymorphisms was assayed by real-time PCR. Serum 25-hydroxyvitamin D (25-OHD) levels were measured by ELISA in blood samples that were obtained at the time of admission to the neonatal intensive care unit.Results: Gestational age (GA) was significantly lower in the RDS group compared with the controls. In univariate analysis, VDR TaqI CT and CC genotypes were associated with the increased risk of RDS (OR = 3.264, p = .001, 95% CI = 1.597-6.672 and OR = 5.222, p < .001, 95% CI = 2.165-12.597, respectively); while VDR FokI showed no association with RDS. In multivariate logistic regression analysis, variant TaqI genotype increased risk of RDS (p = 0.001, OR = 3.464, 95% CI = 1.655-7.251) independent of gestational age, birth weight and gender. 25-OHD levels in the RDS group were significantly lower compared with those in without the RDS group (p = .002). Serum 25-OHD levels were not significantly different among the different FokI and TaqI genotypes in RDS group.Conclusions: This is the first report of association of VDR polymorphism with RDS development in preterm neonates. Current study suggests that VDR TaqI polymorphism may be involved in predisposition to RDS in premature neonates. Further studies are needed to assess the contribution of vitamin D and VDR signaling to the pathogenesis RDS.

A Witteveen-Kolk Syndrome Patient with Reflux Disease and a de novo Deletion of the SIN3A Gene

Introduction

The Witteveen-Kolk syndrome (WITKOS) (OMIM: 613406) is a heterogeneous emerging disorder caused by pathogenic variants or microdeletions encompassing the SIN3A gene (SIN3 Transcription Regulator Family Member A). It is characterized by distinctive facial features, developmental delay, intellectual disability, microcephaly, short stature, and subtle anomalies on brain magnetic resonance imaging (MRI). To date, about 50 patients have been reported in the medical literature.

Patient Presentation

In this article, we reported a patient with classic findings of WITKOS including global developmental delay, microcephaly, hypotonia, vomiting, malnutrition, autistic and dysmorphic facial features, and cardiac abnormalities. Also, a barium esophagogram suggested severe motility disorder and gastroesophageal reflux disease. Affymetrix CytoScan 750K microarray showed a de novo 1.6-Mb deletion at 15q24.1q24.2, including the whole SIN3A gene. We have also summarized the clinical features of WITKOS patients in the medical literature and cardiac abnormalities detected in 4 out of 10 patients in studies that clearly state that cardiac examination was performed in the patients.

Conclusion

Our findings showed that cardiac defects are not uncommon findings in WITKOS. Physicians should also be aware of reflux disease and motility disorder in patients with feeding difficulty together with early cardiac examination in terms of an improved quality of life in WITKOS patients.

Squamous cell carcinoma of the vulva in a virgin patient with Turner syndrome

Two types of gynecologic tumors are commonly described in the Turner syndrome, the first one is gonadoblastoma, which occurs in patients with Y chromosome abnormalities, and the second one is endometrial carcinoma which is mostly related with exogenous estrogen usage. Here, we describe an extremely rare case of squamous cell carcinoma of the vulva in a virgin woman with Turner syndrome. A 35-years old single, virgin woman referred to our Oncology Department with warty, necrotized, exophytic 6-7 cm vulvar mass. She had a history of primary amenorrhea and mosaic Turner syndrome was determined in her karyotype analysis. Biopsy specimen of the vulvar mass revealed squamous cell carcinoma of the vulva, and total vulvectomy with inguinal femoral lymphadenectomy was performed. The postoperative course was uneventful and there has been no recurrence of the disease up to date. Women with Turner syndrome have streak ovaries that produce very low estrogen and the squamous cell carcinoma of the vulva may have developed at an early age with Turner syndrome because of this low estrogen value similar to postmenopausal women. The current case is a special case due to its age of occurrence, virgin and Turner syndrome status.

The effects of commonly used intravitreal steroids on proliferation index of ciliary body-derived mesenchymal stem cells: an in vitro study

AIM

To investigate the effects of commonly used intravitreal steroids on survival and proliferation (namely, proliferation index) of ciliary body-derived mesenchymal stem cells (CB-MSC).

METHODS

CB-MSCs were isolated from newborn rats' eye, and they were expanded in the medium. Commonly used intravitreal steroids such as dexamethasone (Dex) and triamcinolone acetonide (TA) were added into the medium at commonly used concentration in clinical practice (0.1 mg/mL) and at lower concentration (0.01 mg/mL). Proliferation indexes of CB-MSCs were analyzed with the xCELLigence system at nine consecutive times (at 3rd, 6th, 21th, 30th, 45th, 60th, 75th, 90th and 100th h).

RESULTS

Both TA and Dex at both 0.01 mg/mL and 0.1 mg/mL concentrations had negative effect on proliferation indexes of CB-MSC. Although negative effect of TA on proliferation index of CB-MSC at both concentrations was not statistically significant, statistically significant negative effect of Dex at 0.01 mg/mL concentration started 60th h (p = 0.017) and 0.1 mg/mL concentration started 30th h (p = 0.014).

DISCUSSION

Even therapeutic doses of intravitreal corticosteroid agents might have negative effects on limited numbers of stem cells. Especially, Dex caused statistically significant toxic effects on CB-MSCs even at lower concentrations of those used clinically. These novel findings deserve further in vivo investigations.

Evaluation of the etiology of epilepsy and/or developmental delay in children via next-generation sequencing: a single-center experience

Background

We aimed to understand the genetic etiology in children presenting with epilepsy and/or developmental delay by using next-generation sequencing (NGS).

Materials and methods

We included children presenting to our pediatric neurology clinic with a diagnosis of epilepsy and/or developmental delay between January 2019 and December 2021. We evaluated the patients using the NGS equipment in our genetic laboratory.

Results

In total, 90 patients were included in the study. Twenty (34.4%) out of 58 patients who had undergone whole-exome sequencing (WES) had pathogenic or likely pathogenic (P/LP) variants and 11 (18.9%) had variants of unknown significance (VUS). Five (41.6%) out of 12 patients who had undergone whole-genome sequencing had P/LP variants and 5 (41.6%) had VUS. Eleven (55%) out of 20 patients who had undergone WES and chromosomal microarray had P/LP variants and 2 (10%) had VUS. Twenty-six novel variants were described. Twelve patients (13.3%) were diagnosed using a known specific treatment.

Conclusion

NGS aids in precisely diagnosing children with epilepsy and/or developmental delay. Furthermore, it provides a correct prognosis, specific treatment methods, and a multidisciplinary approach.

EEFSEC deficiency: A selenopathy with early-onset neurodegeneration

Inborn errors of selenoprotein expression arise from deleterious variants in genes encoding selenoproteins or selenoprotein biosynthetic factors, some of which are associated with neurodegenerative disorders. This study shows that bi-allelic selenocysteine tRNA-specific eukaryotic elongation factor (EEFSEC) variants cause selenoprotein deficiency, leading to progressive neurodegeneration. EEFSEC deficiency, an autosomal recessive disorder, manifests with global developmental delay, progressive spasticity, ataxia, and seizures. Cerebral MRI primarily demonstrated a cerebellar pathology, including hypoplasia and progressive atrophy. Exome or genome sequencing identified six different bi-allelic EEFSEC variants in nine individuals from eight unrelated families. These variants showed reduced EEFSEC function in vitro, leading to lower levels of selenoproteins in fibroblasts. In line with the clinical phenotype, an eEFSec-RNAi Drosophila model displays progressive impairment of motor function, which is reflected in the synaptic defects in this model organisms. This study identifies EEFSEC deficiency as an inborn error of selenocysteine metabolism. It reveals the pathophysiological mechanisms of neurodegeneration linked to selenoprotein metabolism, suggesting potential targeted therapies.

A Homozygous MYH1 Variant Underlies Autosomal Recessive Isolated Recurrent Rhabdomyolysis

Rhabdomyolysis is a severe condition involving the breakdown of skeletal muscle fibers, leading to the release of muscle components into the bloodstream, which can lead to potential complications such as acute kidney injury and electrolyte imbalances. The etiology of rhabdomyolysis is multifactorial, encompassing traumatic, exertional, metabolic, infectious, toxic, and genetic causes. Genetic causes, including variants in LPIN1, RYR1, and CACNA1S, are increasingly recognized as significant contributors to recurrent rhabdomyolysis. MYH1 has recently been identified as a candidate gene for recurrent rhabdomyolysis with limited evidence originating from a single patient. In this report, we describe a 35-year-old male, born to consanguineous parents, who presented with recurrent rhabdomyolysis attacks, beginning at age 28, characterized by muscle pain, weakness, and episodes of acute kidney injury requiring dialysis. During attacks, the patient exhibited remarkably elevated markers of muscle breakdown and mildly elevated creatine kinase levels between episodes. A muscle biopsy revealed non-specific myopathic changes. Exome sequencing analysis was carried out and revealed a novel homozygous variant (NM_005963.4: c.1825G>A [p.Val609Met]) in MYH1 segregating in a manner compatible with an autosomal recessive pattern. In summary, this case provides confirmatory support for the role of pathogenic MYH1 variants in the pathogenesis of recurrent rhabdomyolysis and emphasizes the importance of comprehensive genetic testing in patients with unexplained recurrent episodes of muscle breakdown. Further cases are necessary to fully elucidate the genotypic and phenotypic spectrum of MYH1-related muscle disorders.

Bi-allelic variants in MRPL49 cause variable clinical presentations, including sensorineural hearing loss, leukodystrophy, and ovarian insufficiency

Combined oxidative phosphorylation deficiency (COXPD) is a rare multisystem disorder that is clinically and genetically heterogeneous. Genome sequencing identified bi-allelic MRPL49 variants in individuals from nine unrelated families with presentations ranging from Perrault syndrome (primary ovarian insufficiency and sensorineural hearing loss) to severe childhood onset of leukodystrophy, learning disability, microcephaly, and retinal dystrophy. Complexome profiling of fibroblasts from affected individuals revealed reduced levels of the small mitochondrial ribosomal subunits and a more pronounced reduction of the large mitochondrial ribosomal subunits. There was no evidence of altered mitoribosomal assembly. The reductions in levels of oxidative phosphorylation (OXPHOS) enzyme complexes I and IV are consistent with a form of COXPD associated with bi-allelic MRPL49 variants, expanding the understanding of how disruption of the mitochondrial ribosomal large subunit results in multisystem phenotypes.