[Genetic testing in neurological diseases: a practical guide]. / Pruebas genéticas en enfermedades neurológicas: guía práctica.

During the last decades, genomic medicine has made it possible to bring the knowledge of molecular genetics to the field of medical consultation. There are several studies that contribute to the diagnosis, the definition of prognoses, as well as the possibility of providing genetic counseling based on accurate scientific data. Advances in genomic sequencing have promoted the reclassification of entities according to an etiological criterion. Such is the case of epileptic encephalopathies, ataxias, dystonias, among many other neurological conditions. Its implementation requires strategies aimed at achieving the best diagnostic yield. This requires a greater understanding of the molecular bases of each of these practices, as well as their scope. They allow reducing the time until a certain diagnosis is made and the possibility, in some cases, of improving the quality of life of those affected with the use of tailored treatments. The objective of this article was to describe current laboratory studies, their scope and emphasize the algorithms for the study of genetic diseases in general, focusing the attention on those specific to neuropediatrics, in order to promote good practices, avoiding confusion, errors, and unnecessary expenditures of money and shortening the so-called "diagnostic odyssey".

Durante las últimas décadas la medicina genómica ha llevado al ámbito de la consulta médica los conocimientos de la genética molecular. Existe un número de estudios que contribuyen en el diagnóstico, la definición de pronósticos y posibilitan un asesoramiento genético basado en datos científicos certeros. En algunas enfermedades, los avances en la secuenciación genómica, ha promovido la reclasificación de entidades según un criterio etiológico, como las encefalopatías epilépticas, las ataxias, las distonías, entre muchas condiciones médicas. Su implementación requiere, por parte de los médicos, de estrategias tendientes a alcanzar el mejor rédito diagnóstico. Es necesario para ello, una mayor comprensión de las bases moleculares de estas prácticas, así como sus alcances. Permiten reducir los tiempos hasta la concreción de un diagnóstico de certeza y la posibilidad, en algunos casos, de mejorar la calidad de vida de los afectados con la utilización de tratamientos a la medida. El objetivo de este artículo fue describir las técnicas de laboratorio actuales, sus alcances y enfatizar los algoritmos de estudio de las enfermedades genéticas, haciendo hincapié en aquellas propias de la neuropediatría, a fin de propiciar las buenas prácticas, evitando confusiones, errores, erogaciones innecesarias de dinero y acortando la llamada "odisea diagnóstica".

Identifying Genetic Etiology in Patients with Intellectual Disability: An Experience in Public Health Services in Northeastern Brazil.

Intellectual disability (ID) is considered a common neuropsychiatric disorder that affects up to 3% of the population. The etiologic origin of ID may be genetic, environmental, and multifactorial. Chromosomopathies are relatively common among the genetic causes of ID, especially in the most severe cases and those associated with dysmorphic features. Currently, the application of new molecular cytogenetics technologies has increasingly allowed the identification of microdeletions, microduplications, and unbalanced translocations as causes of ID. The objective of this study was to investigate the etiology of ID in patients admitted to a public hospital in Northeastern Brazil. In total, 119 patients with ID who had normal karyotypes and fragile X exams participated in this study. The patients were initially physically examined for microdeletion syndromes and then tested using fluorescence in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA), methylation-sensitive polymerase chain reaction (MS-PCR), and chromosome microarray analysis (CMA), according to clinical suspicion. Patients with no diagnoses after FISH, MLPA, and/or MS-PCR evaluations were subsequently tested by CMA. The rate of etiologic diagnoses of ID in the current study was 28%. FISH diagnosed 25 out of 79 tested (31%), MLPA diagnosed 26 out of 79 tested (32%), MS-PCR diagnosed 7 out of 20 tested (35%), and the single nucleotide polymorphism array diagnosed 6 out of 27 tested (22%). Although the CMA is the most complete and recommended tool for the diagnosis of microdeletions, microduplications, and unbalance translocations in patients with ID, FISH, MLPA, and MS-PCR testing can be used as the first tests for specific syndromes, as long as the patients are first physically screened clinically, especially in the public health networks system in Brazil, where resources are scarce.

Changes in the Dentate Gyrus Gene Expression Profile Induced by Levetiracetam Treatment in Rats with Mesial Temporal Lobe Epilepsy.

Temporal lobe epilepsy (TLE) is one of the most common forms of focal epilepsy. Levetiracetam (LEV) is an antiepileptic drug whose mechanism of action at the genetic level has not been fully described. Therefore, the aim of the present work was to evaluate the relevant gene expression changes in the dentate gyrus (DG) of LEV-treated rats with pilocarpine-induced TLE. Whole-transcriptome microarrays were used to obtain the differential genetic profiles of control (CTRL), epileptic (EPI), and EPI rats treated for one week with LEV (EPI + LEV). Quantitative RT-qPCR was used to evaluate the RNA levels of the genes of interest. According to the results of the EPI vs. CTRL analysis, 685 genes were differentially expressed, 355 of which were underexpressed and 330 of which were overexpressed. According to the analysis of the EPI + LEV vs. EPI groups, 675 genes were differentially expressed, 477 of which were downregulated and 198 of which were upregulated. A total of 94 genes whose expression was altered by epilepsy and modified by LEV were identified. The RT-qPCR confirmed that LEV treatment reversed the increased expression of Hgf mRNA and decreased the expression of the Efcab1, Adam8, Slc24a1, and Serpinb1a genes in the DG. These results indicate that LEV could be involved in nonclassical mechanisms involved in Ca2+ homeostasis and the regulation of the mTOR pathway through Efcab1, Hgf, SLC24a1, Adam8, and Serpinb1a, contributing to reduced hyperexcitability in TLE patients.

Diagnostic yield of chromosomal microarray in the largest Latino clinical cohort.

Copy number variants (CNVs) remain a major etiological cause of neurodevelopmental delay and congenital malformations. Chromosomal microarray analysis (CMA) represents the gold standard for CNVs molecular characterization. We applied CMA throughout the patient's clinical diagnostic workup, as the patient's medical provider requested. We collected CMA results of 3380 patients enrolled for 5 years (2016-2021). We found 830 CNVs in 719 patients with potential clinical significance, that is, (i) pathogenic, (ii) likely pathogenic, and (iii) variants of uncertain significance (VUS), from which 10.6% (predominantly involving chromosomes 15 and 22) were most likely the final cause underpinning the patients' clinical phenotype. For those associated with neurodevelopmental phenotypes, the rate of pathogenic or likely pathogenic findings among the patients with CNVs was 60.75%. When considering epileptic phenotypes, it was 59%. Interestingly, our protocol identified two gains harbored in 17q21.31 and 9q34.3, internationally classified initially as VUS. However, because of their high frequency, we propose that these two VUS be reclassified as likely benign in this widely heterogeneous phenotypic population. These results support the diagnostic yield efficiency of CMA in characterizing CNVs to define the final molecular cause of genetic diseases in this cohort of Colombian patients, the most significant sample of patients from a Latino population, and define new benign polymorphic CNVs.

Cornelia de Lange Syndrome Caused by an Intragenic Heterozygous Deletion in RAD21 Detected through Very-High-Resolution Chromosomal Microarray Analysis.

Cornelia de Lange syndrome is a genetic and clinically heterogeneous entity, caused by at least five genes. It is characterized by short stature, gestalt facies, microcephaly, neurodevelopmental disorders, and other anomalies. In this report, we present a 13-year-old female patient with microcephaly, cleft palate, polydactyly, short stature, triangular facies, frontal bossing, a bulbous nose, an overfolded helix, limited pronosupination, and an anomalous uterus. No neurodevelopmental disorders were reported. A chromosomal microarray analysis of 6.5 million markers was performed in the proband and her parents. The results showed a de novo heterozygous microdeletion of exons 9-14 within RAD21, which confirmed the diagnosis of Cornelia de Lange syndrome type 4. Our patient did not show any neurologic phenotype (until the time of diagnosis), although neurodevelopmental disorders are frequently present in patients with Cornelia de Lange syndrome type 4, and despite carrying a deletion that was larger than previously reported. Therefore, unknown genetic modifiers or intrinsic mechanisms of RAD21 variants may exist and should be studied.

LRP5, SLC6A3, and SOX10 Expression in Conventional Ameloblastoma.

Cell proliferation and invasion are characteristic of many tumors, including ameloblastoma, and are important features to target in possible future therapeutic applications. OBJECTIVE: The objective of this study was the identification of key genes and inhibitory drugs related to the cell proliferation and invasion of ameloblastoma using bioinformatic analysis. METHODS: The H10KA_07_38 gene profile database was analyzed by Rstudio and ShinyGO Gene Ontology enrichment. String, Cytoscape-MCODE, and Kaplan-Meier plots were generated, which were subsequently validated by RT-qPCR relative expression and immunoexpression analyses. To propose specific inhibitory drugs, a bioinformatic search using Drug Gene Budger and DrugBank was performed. RESULTS: A total of 204 significantly upregulated genes were identified. Gene ontology enrichment analysis identified four pathways related to cell proliferation and cell invasion. A total of 37 genes were involved in these pathways, and 11 genes showed an MCODE score of ≥0.4; however, only SLC6A3, SOX10, and LRP5 were negatively associated with overall survival (HR = 1.49 (p = 0.0072), HR = 1.55 (p = 0.0018), and HR = 1.38 (p = 0.025), respectively). The RT-qPCR results confirmed the significant differences in expression, with overexpression of >2 for SLC6A3 and SOX10. The immunoexpression analysis indicated positive LRP5 and SLC6A3 expression. The inhibitory drugs bioinformatically obtained for the above three genes were parthenolide and vorinostat. CONCLUSIONS: We identify LRP5, SLC6A3, and SOX10 as potentially important genes related to cell proliferation and invasion in the pathogenesis of ameloblastomas, along with both parthenolide and vorinostat as inhibitory drugs that could be further investigated for the development of novel therapeutic approaches against ameloblastoma.

Consanguinidad no declarada en pacientes peruanos con trastorno del neurodesarrollo detectada a través de micromatrices

Introducción. La consanguinidad es la unión entre personas que comparten un ancestro en común, y cuya descendencia presenta un mayor riesgo de aparición de enfermedades autosómicas recesivas, manifestándose en algunos pacientes como trastornos del neurodesarrollo. Objetivos. Describir la consanguinidad parental no declarada en pacientes menores de 18 años con trastornos del neurodesarrollo, descubierta mediante el análisis cromosómico por micromatrices. Métodos. Se realizó el análisis cromosómico por micromatrices a 967 pacientes con trastorno del neurodesarrollo entre 2016 y 2021. Fueron seleccionados los pacientes con regiones de homocigosidad (ROH) con un valor superior a 0,5%. Resultados. Se evaluó a 288 pacientes, el 58,3% fueron varones y el 29,8% presentó una ROH mayor o igual a 0,5%. Se encontró que el 25,9% y el 0,83% de los pacientes tenían padres con un quinto y primer grado de consanguinidad no declarada, respectivamente. Los departamentos con mayor frecuencia relativa de consanguinidad no declarada por cada 10 000 habitantes fueron Huancavelica, Cajamarca y Apurímac. Conclusión. En Perú, existen regiones donde se evidencia uniones parentales consanguíneas, el cual es un factor de riesgo alto para la aparición de enfermedades recesivas autosómicas en su descendencia, como los trastornos del neurodesarrollo.

Introduction. Consanguinity is the union between people who share a common ancestor, and whose offspring have a higher risk of autosomal recessive diseases, manifesting in some patients as neurodevelopmental disorders. Objectives. To describe non-declared parental consanguinity of patients under 18 years of age with neurodevelopmental disorders, discovered by chromosomal microarray analysis. Methods. Chromosomal microarray analysis was performed on 967 patients with neurodevelopmental disorders between the years 2016-2021 and were selected to patients with regions of homozygosity (ROH) with a value greater than 0.5%. Results. 288 patients were evaluated, 58.3% of the patients were male and 29,8% presented an ROH greater than or equal to 0.5%. We found 25.9% and 0.83% of the patients had their parents of a fifth and first degree of consanguinity not previously declared, respectively. The most frequent neurodevelopmental disorder was delayed psychomotor development with 38.2%. The departments with the highest frequency relative of non declared consanguinity were Huancavelica, Cajamarca y Apurimac. Conclusions. In Peru, non-declared parental consanguinity is frequent, which is a high-risk factor for the appearance of autosomal recessive diseases in their offspring, how neurodevelopment disorders.

Overlapping Spectrum of Craniofacial Microsomia Phenotype in Cat-Eye Syndrome.

This study reports three patients with Cat-eye Syndrome (CES), two of which present a previous clinical diagnosis of Craniofacial microsomia (CFM). Chromosomal microarray analysis (CMA) revealed a tetrasomy of 1,7 Mb at the 22q11.2q11.21 region, which is the typical region triplicated in the CES, in all patients. The most frequent craniofacial features found in individuals with CFM and CES are preauricular tags and/or pits and mandibular hypoplasia. We reinforce that the candidate genes for CFM features, particularly ear malformation, preauricular tags/pits, and facial asymmetry, can be in the proximal region of the 22q11.2 region.

DNA rare copy number alterations in Reinke's Edema

Abstract Introduction: Reinke's Edema (RE) is a laryngeal lesion related to excessive tobacco smoking, voice overuse, and laryngopharyngeal reflux. Although the risk of malignancy has been considered low in literature, RE is classified among precancerous lesions. Objectives: We investigated DNA Copy Number Alterations (CNAs) in specimens of RE and its potential association with malignant progression. Methods: We used array-based comparative genomic hybridization (aCGH, Agilent 4 × 180 K platform) to study eight RE cases. All patients were heavy tobacco users for at least 30 years, and none of them progressed to cancer in the follow-up (>8 years). Two RE presented mild dysplasia, one moderate dysplasia, and no histological alterations were found in the remaining five cases. CNAs were compared with the Database of Genomic Variants (DGV) and genes mapped on altered regions had their functions annotated. Results: Six of eight patients showed different rare copy number alterations on chromosomes 2q37.3, 4q13.1, 4q13.3, 7q11.22, 10p14, and 13q34. A gain of the whole chromosome 8 were detected in one case. Of interest, four of eight RE cases showed copy number imbalances involving genes previously described in several tumor types (RASA3, COL6A3, LINC00707, LINP1, SMR3A, and SMR3B). Conclusion: The genomic imbalances herein found in RE have the potential to contribute to the phenotype but with limited or no risk of cancer. A long-term follow-up in a large series of patients could clarify the mechanisms involved in the malignant progression of RE. Level of evidence: 4.

SNPs Sets in Codifying Genes for Xenobiotics-Processing Enzymes Are Associated with COPD Secondary to Biomass-Burning Smoke.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide; the main risk factors associated with the suffering are tobacco smoking (TS) and chronic exposure to biomass-burning smoke (BBS). Different biological pathways have been associated with COPD, especially xenobiotic or drug metabolism enzymes. This research aims to identify single nucleotide polymorphisms (SNPs) profiles associated with COPD from two expositional sources: tobacco smoking and BBS. One thousand-five hundred Mexican mestizo subjects were included in the study and divided into those exposed to biomass-burning smoke and smokers. Genome-wide exome genotyping was carried out using Infinium Exome-24 kit arrays v. 1.2. Data quality control was conducted using PLINK 1.07. For clinical and demographic data analysis, Rstudio was used. Eight SNPs were found associated with COPD secondary to TS and seven SNPs were conserved when data were analyzed by genotype. When haplotype analyses were carried out, five blocks were predicted. In COPD secondary to BBS, 24 SNPs in MGST3 and CYP family genes were associated. Seven blocks of haplotypes were associated with COPD-BBS. SNPs in the ARNT2 and CYP46A1 genes are associated with COPD secondary to TS, while in the BBS comparison, SNPs in CYP2C8, CYP2C9, MGST3, and MGST1 genes were associated with increased COPD risk.

SOX3 duplication in a boy with 46,XX ovotesticular disorder of sex development and his 46,XX sister with atypical genitalia: Probable germline mosaicism.

Ovotesticular disorders of sex development (OT-DSD) are characterized by ovarian follicles and seminiferous tubules in the same individual, with a wide range of atypical genitalia. We report on two sibs with atypical genitalia and SRY-negative 46,XX DSD, OT-DSD was confirmed only in the boy, while the girl had bilateral ovaries. Chromosome microarray analysis (CMA) showed a 737-kb duplication at Xq27.1 including the entire SOX3 gene in both sibs, which was confirmed by quantitative real time PCR. Also, X chromosome inactivation assay showed random inactivation in both sibs. Whole exome sequencing revealed no pathogenic or likely pathogenic variant. CMA of the parents showed normal results for both, suggesting that germline mosaicism could be the reason of recurrence of this duplication in the siblings. Our results support a pathogenic role of SOX3 overexpression in 46,XX subjects leading to variable DSD phenotypes.

DNA rare copy number alterations in Reinke's Edema.

INTRODUCTION: Reinke's Edema (RE) is a laryngeal lesion related to excessive tobacco smoking, voice overuse, and laryngopharyngeal reflux. Although the risk of malignancy has been considered low in literature, RE is classified among precancerous lesions. OBJECTIVES: We investigated DNA Copy Number Alterations (CNAs) in specimens of RE and its potential association with malignant progression. METHODS: We used array-based comparative genomic hybridization (aCGH, Agilent 4 × 180 K platform) to study eight RE cases. All patients were heavy tobacco users for at least 30 years, and none of them progressed to cancer in the follow-up (>8 years). Two RE presented mild dysplasia, one moderate dysplasia, and no histological alterations were found in the remaining five cases. CNAs were compared with the Database of Genomic Variants (DGV) and genes mapped on altered regions had their functions annotated. RESULTS: Six of eight patients showed different rare copy number alterations on chromosomes 2q37.3, 4q13.1, 4q13.3, 7q11.22, 10p14, and 13q34. A gain of the whole chromosome 8 were detected in one case. Of interest, four of eight RE cases showed copy number imbalances involving genes previously described in several tumor types (RASA3, COL6A3, LINC00707, LINP1, SMR3A, and SMR3B). CONCLUSION: The genomic imbalances herein found in RE have the potential to contribute to the phenotype but with limited or no risk of cancer. A long-term follow-up in a large series of patients could clarify the mechanisms involved in the malignant progression of RE.

Conventional Ameloblastoma. A Case Report with Microarray and Bioinformatic Analysis.

Ameloblastoma is a rare benign epithelial odontogenic neoplasm, but with great clinical implications, as despite its benignity and slow growth, most cases are locally aggressive with a significant recurrence rate. Histological, cellular, or molecular analyses of its pathogenesis have confirmed the complexity of this neoplasm. We present the case of a 20-year-old patient with a suggestive clinical and radiographic diagnosis of ameloblastoma. An incisional biopsy was obtained confirming the diagnosis of conventional ameloblastoma. Left hemimandibulectomy and plate reconstruction were performed. Histopathological analysis of the surgical specimen confirmed the conventional ameloblastoma with a plexiform pattern and significant areas of cystic degeneration and amyloid-like-like deposits. Additionally, a microarray was carried out with bioinformatic analysis for the enrichment, protein interaction, and determination of eight hub genes (CRP, BCHE, APP, AKT1, AGT, ACTC1, ADAM10, and APOA2) related to their pathogenesis.

Characterization of Associated Nonclassical Phenotypes in Patients with Deletion in the WAGR Region Identified by Chromosomal Microarray: New Insights and Literature Review.

WAGR syndrome (Wilms' tumor, aniridia, genitourinary changes, and intellectual disability) is a contiguous gene deletion syndrome characterized by the joint deletion of PAX6 and WT1 genes, located in the short arm of chromosome 11. However, most deletions include other genes, leading to multiple associated phenotypes. Therefore, understanding how genes deleted together can contribute to other clinical phenotypes is still considered a challenge. In order to establish genotype-phenotype correlation in patients with interstitial deletions of the short arm of chromosome 11, we selected 17 patients with deletions identified by chromosomal microarray analysis: 4 new subjects and 13 subjects previously described in the literature with detailed clinical data. Through the analysis of deleted regions and the phenotypic changes, it was possible to suggest the contribution of specific genes to several nonclassical phenotypes, contributing to the accuracy of clinical characterization of the syndrome and emphasizing the broad phenotypic spectrum found in the patients. This study reports the first patient with a PAX6 partial deletion who does not present any eye anomaly thus opening a new set of questions about the functional activity of PAX6.

[Copy number variation and parental consanguinity elevated in newborns of high altitude with major congenital anomalies in Perú]. / Variantes en el número de copias y consanguinidad parental en neonatos de altura con anomalías congénitas en Perú.

Introduction: Congenital abnormalities could be caused by copy number variation or homozygous variants inherited of parental consanguineous. Purpose. Objetive: To show copy number variants and regions of homozygosity in neonates with malformative syndrome or one congenital anomaly major associated to facial dysmorphia or hypotonia. Methodology: Performed chromosomal microarray analysis (CGH/SNP) to 60 neonates with congenital anomalies born in Hospital Antonio Lorena and Hospital Regional Cusco. Results: 70% of the newborns had an abnormal test (n=42); 48,3% (n=29) patients had with regions of homozygosity above to 0,5% (endogamy coefficient up to 1/64). Pathogenic or likely pathogenic copy number variations with or without region of homozygosity were present in 14,2% (n=6) newborns with congenital abnormalities. We founded five patients with uncertain pathogenic copy number variations that have not been described previously and might correlate with phenotype. Conclusion: We founded a similar frequency of CNV in newborns with congenital abnormalities compared to previous reports. Nonetheless, parental consanguinity was increased compared to other countries of South America. This is the first report in Peru that showed to CMA as a useful diagnostic method in patients with congenital abnormalities and is pioneer in relation to other countries in Latinoamerica.

Introducción: Las variantes en el número de copias son un tipo de cambios en el genoma provocan anomalías congénitas. Objetivo: Determinar las variantes en el número de copias y el grado de consanguinidad parental en neonatos con síndromes malformativos o una anomalía congénita mayor asociado a dismorfia facial o hipotonía. Materiales y métodos: Se realizó el análisis cromosómico por micromatrices a 60 neonatos con anomalías congénitas evaluados en los Hospitales Antonio Lorena y Regional de Cusco. Resultados: Del total de pacientes estudiados, el 70% tuvo un resultado anómalo; de los cuales en el 14,2% de los recién nacidos se encontraron variantes en el número de copias patogénicas o probablemente patogénicas asociadas o no a regiones de homocigosidad que tuvieron relación con las anomalías congénitas descritas. En el 48,3% de los recién se encontró regiones de homocigosidad mayores a 0,5% (coeficiente de endogamia superior a 1/64). Por otro lado, encontramos cinco variantes en el número de copias de patogenicidad desconocida que no se han descrito anteriormente y podrían estar relacionadas con el fenotipo. Conclusión: Nuestra tasa de detección de las variantes en el número de copias está en relación con los reportes internacionales previos. Sin embargo, el porcentaje de neonatos con consanguinidad parental se encuentra por encima de lo reportado previamente, siendo superior a otras regiones de Sudamerica. Este es el primer reporte en el Perú, y es pionero en Latinoamérica al utilizar el análisis cromosómico por micromatrices en esta cohorte específica de pacientes.

Gene Expression Profile Induced by Two Different Variants of Street Rabies Virus in Mice.

Pathogenicity and pathology of rabies virus (RABV) varies according to the variant, but the mechanisms are not completely known. In this study, gene expression profile in brains of mice experimentally infected with RABV isolated from a human case of dog rabies (V2) or vampire bat-acquired rabies (V3) were analyzed. In total, 138 array probes associated with 120 genes were expressed differentially between mice inoculated with V2 and sham-inoculated control mice at day 10 post-inoculation. A single probe corresponding to an unannotated gene was identified in V3 versus control mice. Gene ontology (GO) analysis revealed that all of the genes upregulated in mice inoculated with V2 RABV were involved in the biological process of immune defense against pathogens. Although both variants are considered pathogenic, inoculation by the same conditions generated different gene expression results, which is likely due to differences in pathogenesis between the dog and bat RABV variants. This study demonstrated the global gene expression in experimental infection due to V3 wild-type RABV, from the vampire bat Desmodus rotundus, an important source of infection for humans, domestic animals and wildlife in Latin America.

Phenotypic and mutational spectrum of ROR2-related Robinow syndrome.

Robinow syndrome is characterized by a triad of craniofacial dysmorphisms, disproportionate-limb short stature, and genital hypoplasia. A significant degree of phenotypic variability seems to correlate with different genes/loci. Disturbances of the noncanonical WNT-pathway have been identified as the main cause of the syndrome. Biallelic variants in ROR2 cause an autosomal recessive form of the syndrome with distinctive skeletal findings. Twenty-two patients with a clinical diagnosis of autosomal recessive Robinow syndrome were screened for variants in ROR2 using multiple molecular approaches. We identified 25 putatively pathogenic ROR2 variants, 16 novel, including single nucleotide variants and exonic deletions. Detailed phenotypic analyses revealed that all subjects presented with a prominent forehead, hypertelorism, short nose, abnormality of the nasal tip, brachydactyly, mesomelic limb shortening, short stature, and genital hypoplasia in male patients. A total of 19 clinical features were present in more than 75% of the subjects, thus pointing to an overall uniformity of the phenotype. Disease-causing variants in ROR2, contribute to a clinically recognizable autosomal recessive trait phenotype with multiple skeletal defects. A comprehensive quantitative clinical evaluation of this cohort delineated the phenotypic spectrum of ROR2-related Robinow syndrome. The identification of exonic deletion variant alleles further supports the contention of a loss-of-function mechanism in the etiology of the syndrome.

A Novel Look at Dosage-Sensitive Sex Locus Xp21.2 in a Case of 46,XY Partial Gonadal Dysgenesis without NR0B1 Duplication.

A region of 160 kb at Xp21.2 has been defined as dosage-sensitive sex reversal (DSS) and includes the NR0B1 gene, considered to be the candidate gene involved in XY gonadal dysgenesis if overexpressed. We describe a girl with 46,XY partial gonadal dysgenesis carrying a 297 kb duplication at Xp21.2 upstream of NR0B1 initially detected by chromosomal microarray analysis. Fine mapping of the breakpoints by whole-genome sequencing showed a tandem duplication of TASL (CXorf21), GK and partially TAB3, upstream of NR0B1. This is the first description of an Xp21.2 duplication upstream of NR0B1 associated with 46,XY partial gonadal dysgenesis.

Duplication of 12q24.21q24.33 in a Girl with Epilepsy, Expanding the Phenotype.

Introduction: Duplication of 12q is characterized by craniofacial dysmorphia, growth failure, occasional brain malformations, abnormalities of the extremities, skeletal and thoracic malformations, cardiovascular defects, anogenital abnormalities like cryptorchidism, psychomotor delay, and intellectual disability. Case presentation: We describe a female patient with typical manifestations of duplication 12q and epilepsy. She had a normal 46,XX karyotype. The microarray assay exhibited a 19.35-Mb gain at 12q24.21q24.33 due to ins(21;12)(p11.2;q24.21q24.33)mat. Discussion and Conclusion: The duplicated region in the patient encompasses 219 genes, 24 considered as pathological. No relation between epilepsy and the genes reported as pathological has been reported.

Congenital chromoanagenesis in the routine postnatal chromosomal microarray analyses.

Chromosomal microarray analyses (CMA) have greatly increased both the yield and diagnostic accuracy of postnatal analysis; it has been used as a first-tier cytogenetic test in patients with intellectual disability, autism spectrum disorder, and multiple congenital abnormalities. During the last 15 years, we performed CMA in approximately 8,000 patients with neurodevelopmental and/or congenital disorders, of which 13 (0.16%) genetically catastrophic complex chromosomal rearrangements were identified. These ultrarare rearrangements showed clustering of breakpoints, characteristic of chromoanagenesis events. Al1 13 complex events display underlying formation mechanisms, originating either by a synchronization of the shattering of clustered chromosome regions in which regional asynchrony of DNA replication may be one of the main causes of disruption. We provide an overview of the copy number profiling in these patients. Although several previous studies have suggested that chromoanagenesis is often a genetic disease source in postnatal diagnostic screening, due to either the challenge of clinical interpretation of these complex rearrangements or the limitation of microarray resolution relative to the small size and complexity of chromogenic induced chromosome abnormalities, bringing further attention and to study its occurrence in the clinical setting is extremely important.