Next-generation sequencing-based genetic testing and phenotype correlation in retinitis pigmentosa patients from India

Purpose: Inherited retinal dystrophies (IRD) are a heterogeneous group of retinal diseases leading to progressive loss of photoreceptors through apoptosis. Retinitis pigmentosa (RP) is considered the most common form of IRD. Panel?based testing in RP has proven effective in identifying the causative genetic mutations in 70% and 80% of the patients. This is a retrospective, observational, single?center study of 107 RP patients who had undergone next?generation sequencing?based targeted gene panel testing for IRD genes. These patients were inspected for common phenotypic features to arrive at meaningful genotype–phenotype correlation. Methods: Patients underwent complete ophthalmic examination, and blood was collected from the proband for DNA extraction after documenting the pedigree. Targeted Next Generation Sequencing (NGS) was done by panel?based testing for IRD genes followed by co?segregation analysis wherever applicable. Results: Of the 107 patients, 72 patients had pathogenic mutations. The mean age of onset of symptoms was 14 ± 12 years (range: 5–55). Mean (Best Corrected Visual Acuity) BCVA was 6/48 (0.9 logMAR) (range 0.0–3.0). At presentation, over one?third of eyes had BCVA worse than 6/60 (<1 logMAR). Phenotype analysis with the gene defects showed overlapping features, such as peripheral well?defined chorioretinal atrophic patches in patients with CERKL, PROM1, and RPE65 gene mutations and large macular lesions in patients with RDH12 and CRX gene mutations, respectively. Nummular or clump?like pigmentation was noted in CRB1, TTC8, PDE6A, and PDE6B. Conclusion: NGS?based genetic testing can help clinicians to diagnose RP more accurately, and phenotypic correlations can also help in better patient counselling with respect to prognosis and guidance regarding ongoing newer gene?based therapies.

Novel PAX9 compound heterozygous variants in a Chinese family with non-syndromic oligodontia and genotype-phenotype analysis of PAX9 variants

Abstract Studies have reported that >91.9% of non-syndromic tooth agenesis cases are caused by seven pathogenic genes. Objective To report novel heterozygous PAX9 variants in a Chinese family with non-syndromic oligodontia and summarize the reported genotype-phenotype relationship of PAX9 variants. Methodology We recruited 28 patients with non-syndromic oligodontia who were admitted to the Hospital of Stomatology Hebei Medical University (China) from 2018 to 2021. Peripheral blood was collected from the probands and their core family members for whole-exome sequencing (WES) and variants were verified by Sanger sequencing. Bioinformatics tools were used to predict the pathogenicity of the variants. SWISS-MODEL homology modeling was used to analyze the three-dimensional structural changes of variant proteins. We also analyzed the genotype-phenotype relationships of PAX9 variants. Results We identified novel compound heterozygous PAX9 variants (reference sequence NM_001372076.1) in a Chinese family with non-syndromic oligodontia: a new missense variant c.1010C>A (p.T337K) in exon 4 and a new frameshift variant c.330_331insGT (p.D113Afs*9) in exon 2, which was identified as the pathogenic variant in this family. This discovery expands the known variant spectrum of PAX9; then, we summarized the phenotypes of non-syndromic oligodontia with PAX9 variants. Conclusion We found that PAX9 variants commonly lead to loss of the second molars.

Cellular consequences of small supernumerary marker chromosome derived from chromosome 12: mosaicism in daughter and father

Constitutional genomic imbalances are known to cause malformations, disabilities, neurodevelopmental delay, and dysmorphia and can lead to dysfunctions in the cell cycle. In extremely rare genetic conditions such as small supernumerary marker chromosomes (sSMC), it is important to understand the cellular consequences of this extra marker, as well the factors that contribute to their maintenance or elimination through successive cell cycles and phenotypic impact. The study of chromosomal mosaicism provides a natural model to characterize the effect of aneuploidy on genome stability and compare cells with the same genetic background and environment exposure, but differing in the presence of sSMC. Here, we report the functional characterization of different cell lines from two familial patients with mosaic sSMC derived from chromosome 12. We performed studies of proliferation dynamics, stability, and variability of these cells using fluorescent in situ hybridization (FISH), sister chromatid exchanges (SCE), and conventional staining. We also quantified the telomere-related genomic instability of sSMC cells using 3D telomeric profile analysis by quantitative-FISH. sSMC cells exhibited differences in the cell cycle dynamics compared to normal cells. First, the sSMC cells exhibited lower proliferation index and higher frequency of SCE than normal cells, associated with a higher level of chromosomal instability. Second, sSMC cells exhibited more telomeric-related genomic instability. Lastly, the differences of sSMC cells distribution among tissues could explain different phenotypic repercussions observed in patients. These results will help in our understanding of the sSMC stability, maintenance during cell cycle, and the cell cycle variables involved in the different phenotypic manifestations.

Mutation Analysis of the CYP4F22 Gene in a Family with Autosomal Recessive Congenital Ichthyosis / 罕见病研究

Autosomal recessive congenital ichthyosis (ARCI) is a rare hereditary cornification disorder presented with abnormal skin scaling. In this paper, we used next-generation sequencing to determine the variants in a Chinese ARCI patient. We used sanger sequencing to verify bidirectionally the DNA from the proband and her parents. Results showes that two compound heterozygous variants (c.235G > T and c.641delG) in CYP4F22 gene, and both of the mutations are novel. The parents were heterozygous carriers. The two variants are classified as pathogenic variants based on interpretation guidelines. The compound heterozygous mutations in CYP4F22 gene were the causative mutations responsible for ARCI in proband.

Clinical, Pathological and Genetic Analysis of Alport Syndrome in Children / 罕见病研究

  Objective  To explore the phenotype-genotype correlation of Alport syndrome in children.  Methods  Retrospectively analyze the clinical and pathological features of 55 patients with Alport syndrome with COL4A mutations detected by second-generation sequencing, who were treated at Beijing Children's Hospital from January 2016 to December 2020.  Results  A total of 55 children with Alport syndrome were included. All cases had hematuria, including 31 cases (56.4%) with gross hematuria and 24 cases (43.6%) with microscopic hematuria. A total of 39 (70.9%) patients also had proteinuria. Extrarenal manifestations were pres- ent in 12 patients (21.8%). 36(65.4%) patients had a family history of Alport syndrome. 32 patients underwent pathological examination and 23 of them had the specific pathological changes of Alport syndrome. In 55 cases, 36 (65.4%) were diagnosed as X-linked Alport syndrome, 5(9.1%) were diagnosed as autosomal recessive Alport syndrome, 10(18.2%) were diagnosed as autosomal dominate Alport syndrome, and 4(7.3%) were diagnosed as digenic Alport syndrome. Missense mutations in COL4A genes accounted for 62.5%, 67.5% of missense mutations resulted in glycine substitution. There were statistical significances in proteinuria degree and hearing loss between male and female patients with XLAS (P < 0.05) as well as statistical significance in the degree of proteinuria between autosomal recessive Alport syndrome and autosomal dominate Alport syndrome (P=0.044), and there was critical statistical significance in the age of onset. There was statistical significance in hearing loss between children with renal impairment and children with normal renal function (P=0.001).  Conclusions  Most of the pathogenic variants in COL4A genes that cause Alport syndrome result in glycine substitutions. The degree of proteinuria and hearing loss of males with XLAS were greater than those of females. The degree of proteinuria in autosomal recessive Alport syndrome was greater than that of children with autosomal dominate Alport syndrome, and the age of onset was earlier than that of autosomal dominate Alport syndrome. Renal manifestation was more severe in children with hearing loss. The early clinical manifestations of Alport syndrome are diverse and pathological manifestations may be atypical. The application of next-generation sequencing can reduce misdiagnosises of Alport syndrome.

Reporte de caso: síndrome de Schaaf Yang / Case report: Schaag Yang síndrome

RESUMEN Introducción: El síndrome Schaaf Yang (SHFYNG) constituye un desorden multisistémico caracterizado por un grupo de signos y síntomas relacionados con alteraciones genéticas, congénitas y de expresión clínica multivariable. Fue descrito por primera vez por el Dr. Schaaf y la Dra. Yaping, profesores de Genética Molecular y Humana de la Universidad de Houston y Baylor, respectivamente, en 2013 (1). El síndrome SHFYNG tiene una herencia autosómica dominante con una mutación presente en el alelo paterno, ya que el gen MA-GEL2 tiene una impronta materna y solo se expresa el alelo paterno. A diferencia de otras patologías autosómicas dominantes clásicas, el síndrome SHFYNG puede saltar varias generaciones siempre que la mutación resida en el cromosoma materno. Presentación del caso. Preescolar femenina, con antecedente de estancia en UCIN por hipotonía neonatal y pobre succión, bronquitis y neumonía. Su fenotipo está caracterizado por facies hipotónicas, frente prominente, epicanto interno, pómulos prominentes, puente nasal bajo, nariz ancha, labio superior delgado, orejas aladas, cuello corto y obesidad central. Presenta retraso en el neurodesarrollo, lenguaje y psicomotor. Estudios genéticos: cariotipo 46,XX e hibridación genómica comparativa con patrón genómico normal, sexo femenino, en exoma trío se identifica una variante patogénica: c.1996dupC (p.Gln666Profs*47) en el gen MAGEL2 asociada con SHFYNG. Conclusión. Se informa el primer reporte de este síndrome a nivel nacional con una incidencia mundial muy baja, estimándose aproximadamente <1/1.000.000 de nacidos vivos, lo que permite ampliar el conocimiento y sospechar patologías de difícil diagnóstico como esta.

ABSTRACT Introduction: Schaaf Yang Syndrome (SHFYNG) is a multisystemic disorder characterized by a group of signs and symptoms related to genetic, congenital, and multivariate clinical alterations. It was first described by Dr. Schaaf and Dr. Yaping, professors of Molecular and Human Genetics at the University of Houston and Baylor, respectively, in 2013 (1). SHFYNG has an autosomal dominant inheritance with a mutation located in the paternal allele, since the MAGEL2 gene has a maternal imprint and only the paternal allele is expressed. Unlike other classic autosomal dominant pathologies, SHFYNG syndrome can skip several generations, as long as the mutation resides on the maternal chromosome. Presentation of the case: Female preschooler, with a history of stay in the Neonatal Intensive Care Unit, due to neonatal hypotonia and poor suction, bronchitis, and pneumonia. Her phenotype is distinguished by hypotonic facies, prominent forehead, internal epican-thus, prominent cheekbones, low nasal bridge, broad nose, thin upper lip, winged ears, short neck, and central obesity. She presents neurodevelopmental, language, and psychomotor delay. Genetic studies: 46,XX karyotype, comparative genomic hybridization: normal genomic pattern, female sex, trio exam a pathogenic variant c.1996dupC (p.Gln666Profs*47) in the MAGEL2 gene associated with SHFYNG syndrome. Conclusion: It is reported to be the first national report of this syndrome, with a very low worldwide incidence, estimating approximately <1 / 1,000,000 live births, which allows us to expand knowledge and suspect difficult-to-diagnose pathologies like this one.

Progress in the pathogenesis and genotype-phenotype of Angelman syndrome / 中华实用儿科临床杂志

Angelman syndrome (AS) is a neurodevelopmental disorder characterized by severe developmental delay, intellectual disability, exuberant behavior with happy demeanor, speech impairment, and epileptic seizures.The loss of UBE3A allele on maternal chromosome 15q11-13 is the main cause of AS.However, the pathogenesis and genotype-phenotype of AS is not yet clear.This study aims to review the research progress of AS.

Síndrome de Silver-Russell. Aspectos clínicos y etiopatológicos de una entidad ejemplo de impronta genómica / Silver-Russell syndrome. Clinical and etiopathological aspects of a model genomic imprinting entity

El síndrome de Silver-Russell se caracteriza por retraso del crecimiento intrauterino asimétrico, con circunferencia craneal normal, barbilla pequeña y puntiaguda, que proporciona un aspecto de rostro triangular. Puede, además, presentar asimetría corporal, entre otros. Tiene una incidencia mundial estimada de 1 en 30 000-100 000 nacimientos, aunque este número es, probablemente, subestimado. En alrededor del 60 % de los casos, se puede identificar una causa molecular y la principal es la hipometilación del alelo paterno en la región de control de impresión 1 localizado en 11p15.5-p15.4. Realizar el diagnóstico de esta entidad, excluir los diagnósticos diferenciales y conocer las correlaciones (epi)genotipo-fenotipo son necesarios para realizar el adecuado seguimiento, brindar las opciones terapéuticas disponibles y el oportuno asesoramiento genético familiar. El objetivo del presente artículo es mostrar el estado actual del síndrome de Silver-Russell, un ejemplo de trastorno de impronta genómica.

Silver-Russell syndrome is characterized by asymmetrical intrauterine growth retardation, with normal head circumference and small, pointed chin, which results in a triangular face. It can also include body asymmetry, among other characteristics. Its global incidence is estimated at 1 in 30 000-100 000 births, even though this figure may be underestimated. In approximately 60 % of cases, a molecular cause can be identified, and the main one is hypomethylation of the paternal allele at the imprinting control region 1 located at 11p15.5-p15.4. It is necessary to make the diagnosis of this entity, exclude differential diagnoses, and know (epi)genotype-phenotype correlations in order to ensure an adequate follow-up, provide available therapeutic options, and offer a timely family genetic counseling. The objective of this article is to describe the current status of the Silver-Russell syndrome, a model of genomic imprinting disorder.

Genotype-Phenotype Variations of Renal Complications in Fabry Disease Q279X Mutation

Abstract In more than 800 GLA gene mutations causing Fabry Disease (FD), renal involvement vary according to the α-GAL A mutation. The aim is to describe the genotype/phenotype variations of renal complications in two siblings with confirmed FD with the mutation p.Q279X in exon 6. We present a retrospective study of two venezuelan male siblings, ages 34 (patient 1) and 33 (patient 2), evaluated by general lab tests, renal ultrasound, renal scintigram , and renal biopsy. Fabry disease diagnose was made by α-galactosidase A activity determined in dried blood spot. Genomic DNA was sequenced by Sanger method. Patient 1 developed CKD grade 5 and high blood pressure, treated by hemodialysis during 8 years. Patient 2 showed GFR >60 ml/min, and proteinuria less than 600 mg/24H. Renal biopsy showed segmental sclerotic lesions and hypertrophic podocytes with vacuolated cytoplasm. Both patients received ERT every two weeks since 2003. Patient 1 died because dialysis complications (hyperparathyroidism, cardiomyopathy). The genotype/phenotype variation of the c.835C>T mutation (p.Gln279Ter. Q279X) in exon 6 of the GLA gene can express an important renal variation with a wide range of clinical manifestations that cannot be predicted, therefore, an early nephrological evaluation and periodic follow-up of these patients are necessary.

Aspectos genómicos, transcriptómicos y del diagnóstico en el síndrome de Down / Genomic, transcriptomic, and diagnostic features of Down syndrome

El síndrome de Down es causado por la presencia de una tercera copia del cromosoma 21 y fue descrito por primera vez en 1838 por Jean-Etienne-Dominique, y más tarde por John Langdon Haydon Down en 1866, mientras trabajaba como superintendente médico en el Asilo Real de Earlswood. Desde ese momento, la comunidad científica puso grandes esfuerzos en tratar de elucidar diversos aspectos que influyen en la naturaleza de esta condición, y que determinan su incidencia y factores de riesgo. De igual manera, se ha puesto interés en los genes involucrados en esta enfermedad, la relación genotipo-fenotipo, la expresión del fenotipo, la variabilidad del material genético y las consecuencias transcripcionales que se producen al tener una tercera copia, ya sea parcial o total, del cromosoma 21. Además, se han invertido esfuerzos en identificar biomarcadores y en diseñar metodologías de diagnóstico prenatal no invasivo que sean altamente eficientes para un mejor diagnóstico del síndrome de Down, y así reducir su impacto negativo en las madres gestantes, al proveerlas de información neutral y precisa acerca de vivir con un hijo con síndrome de Down, y darles autonomía en la decisión de la continuación de su embarazo

Down syndrome is caused by the presence of a third copy of chromosome 21 and was first described by Jean-Etienne-Dominique in 1838, and later by John Langdon Haydon Down in 1866, while working as a medical superintendent in the Royal Earlswood Asylum. Since, the scientific community has placed great efforts in trying to elucidate different influencing features in the nature of this condition that determine their incidence and risk factors. In addition, especial attention has been given to the genes involved in this disease, the genotype-phenotype relationship, the expression of the phenotype, the variability of the genetic material and the transcriptional consequences that are produced by having a third copy, either partial or total, of chromosome 21. Additionally, efforts have been invested in identifying biomarkers and designing noninvasive prenatal methodologies that are highly efficient for a better diagnosis of Down syndrome, in order to reduce its negative impact in pregnant mothers, by providing them with neutral and accurate information about life with a child with Down syndrome, as well as providing the autonomy in the decision to continue their pregnancy

Clinical and molecular profile of newborns with confirmed or suspicious congenital adrenal hyperplasia detected after a public screening program implementation / Perfil clínico e molecular de recém-nascidos com suspeita ou confirmação de hiperplasia adrenal congênita após a implementação de um programa público de triagem neonatal

Abstract Objective: To describe the results obtained in a neonatal screening program after its implementation and to assess the clinical and molecular profiles of confirmed and suspicious congenital adrenal hyperplasia cases. Methods: A cross-sectional study was conducted. Newborns with suspected disease due to high 17-hydroxyprogesterone levels and adjusted for birth weight were selected. Classical congenital adrenal hyperplasia (salt-wasting and simple virilizing forms) was diagnosed by an increase in 17-hydroxyprogesterone levels as confirmed in the retest, clinical evaluation, and genotype determined by SNaPshot and multiplex ligation-dependent probe amplification. Results: After 24 months, 15 classic congenital adrenal hyperplasia cases were diagnosed in a total of 217,965 newborns, with an estimated incidence of 1:14,531. From 132 patients, seven non-classical and 14 heterozygous patients were screened for CYP21A2 mutations, and 96 patients presented false positives with wild type CYP21A2. On retest, increased 17-hydroxyprogesterone levels were found in classical congenital adrenal hyperplasia patients and showed significant correlation with genotype-related classical genital adrenal hyperplasia. The most frequent mutations were IVS2-13A/C>G followed by gene deletion or rearrangement events in the classical form. In non-classical and heterozygous diseases, p.Val282Leu was the most common mutation. Conclusions: The results underscore the effectiveness of congenital adrenal hyperplasia neonatal screening in the public health system and indicate that the adopted strategy was appropriate. The second sample collection along with genotyping of suspected cases helped to properly diagnose both severe and milder cases and delineate them from false positive patients.

Resumo Objetivo: Descrever os resultados obtidos em um programa de triagem neonatal após sua implementação e avaliar os perfis clínicos e moleculares de casos confirmados e suspeitos de hiperplasia adrenal congênita. Métodos: Foi feito um estudo transversal. Recém-nascidos com suspeita da doença devido aos altos níveis de 17-alfa-hidroxiprogesterona e ajustados pelo peso ao nascer foram selecionados. A hiperplasia adrenal congênita clássica (forma perdedora de sal e forma virilizante simples) foi diagnosticada por um aumento nos níveis de 17-alfa-hidroxiprogesterona confirmado no reteste, avaliação clínica e genótipo determinado com o uso do ensaio SNaPshot e amplificação multiplex de sondas dependente de ligação. Resultados: Após 24 meses, 15 casos clássicos de hiperplasia adrenal congênita foram diagnosticados em 217.965 recém-nascidos, com uma incidência estimada de 1:14.531. De 132 pacientes, sete não clássicos e 14 heterozigotos foram submetidos à triagem para mutações no gene CYP21A2 e 96 pacientes apresentaram resultados falso-positivos com CYP21A2 do tipo selvagem. No reteste, níveis aumentados de 17-alfa-hidroxiprogesterona foram encontrados em pacientes com hiperplasia adrenal congênita clássica e mostraram correlação significativa com HAC clássica relacionada ao genótipo. As mutações mais frequentes foram IVS2-13A/C>G, seguidas de deleção gênica ou eventos de rearranjo na forma clássica. Em casos de doenças não clássicas e heterozigose, a mutação p.Val282Leu foi a mais comum. Conclusões: Os resultados ressaltam a eficácia da triagem neonatal para a hiperplasia adrenal congênita no sistema público de saúde e indicam que a estratégia adotada foi adequada. A segunda coleta de amostras, juntamente com a genotipagem dos casos suspeitos, ajudou a diagnosticar adequadamente os casos graves e mais leves e diferenciá-los de pacientes com resultado falso-positivo.

Special AT-rich binding protein 2-associated syndrome: a case report and literature review / 中华神经科杂志

Objective@#To retrospectively analyse the genetic characteristics, diagnosis, treatment and prognosis of special AT-rich binding protein 2 (SATB2)-associated syndrome.@*Methods@#Clinical data of one case of SATB2-associated syndrome diagnosed in Children′s Hospital Affiliated to Zhengzhou University in January 2018, were collected including clinical test, treatment plan, follow-up outcomes. The clinical characteristics of SATB2-associated syndrome were analyzed, and literature review was conducted.@*Results@#The female proband, eight-year-old, were admitted with the clinical manifestations including epilepsy seizures, delayed language development, sparse hair, long face, prominent forehead, long nose, lower eyelid cleft oblique, low ear, smooth philtrum, small mandible, sparse teeth arrangement, and lack of some teeth. The intelligence quotient score was 49. The brain magnetic resonance imaging showed myelinated dysplasia. Long-range video-electroencephalography showed spike-wave activity, slow spike-wave discharges in the bilateral middle and posterior temporal regions. The trio whole exome sequencing (trio WES) test showed that the proband carried a heterozygous nonsense mutation c.1300 C>T (p.Gln434Ter) in the SATB2 gene, and the muation was de novo comfirmed by pedigree analysis. Thirty-seven literatures relevant to SATB2-associated syndrome, from January 1989 to June 2019, were retrieved. Threre were 23 overseas literatures and one domestic report, including a total number of 158 cases. There were 49 missense mutations, 38 nonsense mutations, 32 frameshift mutations, seven splicing-site mutations, six translocation mutations, one insertion mutation, 22 gene-deletions and three gene-duplications. Among the 158 reported cases, 90 were male and 62 female, sex was not described in six cases. One hundred and fifty-eight (100.0%) patients had mental retardation, 44 (30.6%) with growth retardation, 107 (84.3%) with facial deformities, 70 (45.5%) with cleft palate, 135 (98.5%) with dental abnormalities, 66 (43.4%) with language retardation, 29 (20.0%) with epileptic seizures, and 50 (46.3%) with neuroimaging abnormalities.@*Conclusions@#The main clinical manifestations of SATB2-related syndromes are severe developmental retardation, low intelligence, delayed language development, language deficiency, high palatal arch and cleft palate, rare epilepsy seizures, dental anomalies and scant hair. The study identified a novel nonsense mutation c. 1300 C>T (p. Gln434Ter) in the SATB2 gene, which is responsible for the development of SATB2-associated syndrome.

Primary Hyperoxaluria in Korean Pediatric Patients

BACKGROUND: Primary hyperoxaluria (PH), a rare inborn error of glyoxylate meta bolism causing overproduction of oxalate, is classified into three genetic subgroups: type 1–3 (PH1–PH3) caused by AGXT, GRHPR , and HOGA1 gene mutations, respectively. We performed a retrospective case series study of Korean pediatric patients with PH.METHODS: In total, 11 unrelated pediatric patients were recruited and their phenotypes and genotypes were analyzed by a retrospective review of their medical records.RESULTS: Mutational analyses revealed biallelic AGXT mutations (PH1) in nine patients and a single heterozygous GRHPR and HOGA1 mutation in one patient each. The c.33dupC was the most common AGXT mutation with an allelic frequency of 44%. The median age of onset was 3 months (range, 2 months-3 years), and eight patients with PH1 presented with end stage renal disease (ESRD). Patients with two truncating mutations showed an earlier age of onset and more frequent retinal involvement than patients with one truncating mutation. Among eight PH1 patients presenting with ESRD, five patients were treated with intensive dialysis followed by liver transplantation (n=5) with/without subsequent kidney transplantation (n=3).CONCLUSION: Most patients presented with severe infantile forms of PH. Patients with two truncating mutations displayed more severe phenotypes than those of patients with one truncating mutation. Sequential liver and kidney transplantation was adopted for PH1 patients presenting with ESRD. A larger nation-wide multicenter study is needed to confirm the genotype-phenotype correlations and outcomes of organ transplantation.

Abordaje de las cardiopatías familiares desde la Medicina genómica / Approach to familial heart diseases from Genomic Medicine

Resumen Las cardiopatías familiares son un grupo de enfermedades con alta heterogeneidad clínica y genética. Debido a que pueden heredarse y a su asociación con la muerte súbita, se recomienda efectuar un estudio clínico y genético del individuo afectado y su familia a través de una unidad especializada. Con la implementación de la secuenciación masiva se ha facilitado el acceso a los estudios genéticos en la práctica clínica de forma más rutinaria. Sin embargo, dada la gran cantidad de información obtenida se hacen necesarios el análisis y la interpretación adecuada de los resultados para garantizar un diagnóstico correcto. Este nuevo modelo de medicina amplía nuestra comprensión sobre estas patologías, gracias a que optimiza el diagnóstico, da una mejor aproximación pronóstica de los pacientes e identifica individuos asintomáticos en riesgo. Este artículo pretende realizar una revisión de la arquitectura genética de las enfermedades cardíacas hereditarias y proporcionar un enfoque práctico acerca de la utilidad de la Medicina genómica en el diagnóstico, la estratificación del riesgo y el estudio familiar en pacientes con este tipo de patologías.

Abstract The familial heart diseases are a group of diseases with high clinical and genomic heterogeneity. As they can be inherited and are associated with sudden death, it is recommended to perform a clinical and genetic study of the individual affected, as well as the family, in a specialised unit. The implementation of massive sequencing has meant that access to genetic studies is available in the most routine clinical practice. However, due to the large amount of information obtained, the results have to analysed and interpreted to ensure a correct diagnosis. This new medicine model widens the understanding of these diseases, as due to the diagnosis being optimised, it provides a more accurate prognosis for the patients, and identifies asymptomatic individuals at risk. A review is presented on the genetic architecture of heritable heart disease and provides a practical approach on the usefulness of Genomic Medicine in the diagnosis, risk stratification, and the familial study in patients with these types of heart diseases.

Nueva mutación del gen TSC2 en un paciente pediátrico con diagnóstico clínico de esclerosis tuberosa / Novel mutation in TSC2 gene in pediatric patient with clinical diagnosis of tuberous sclerosis

El complejo de esclerosis tuberosa es un desorden neurocutáneo autosómico dominante causado por mutaciones en los genes TSC1 o TSC2. El diagnóstico se basa en criterios clínicos o el criterio genético. La presentación clínica es altamente variable y las manifestaciones de la enfermedad pueden desarrollarse durante toda la vida. Se reporta el caso de un niño que cumple criterios clínicos para el diagnóstico de esclerosis tuberosa y cuyo estudio molecular identificó una variante nueva del gen TSC2. Se trata de una mutación sin sentido, esporádica, no reportada previamente (c.583_586dupATCG) localizada en el exón 6, que provoca un codón de parada temprano y altera la estructura de la proteína. Puede considerarse una variante patogénica por el tipo de mutación y permite ampliar el espectro de variantes del gen TSC2 como causa del complejo de esclerosis tuberosa.

Tuberous sclerosis complex (TSC) is a neurocutaneous autosomal dominant disorder that results from mutations within either the TSC1 gene or the TSC2 gene. Diagnosis is based on well-established clinical criteria or genetic criteria. Clinical features are highly variable and could be developing over the life. We present a case of TSC with a molecular test that identified a novel variant in TSC2 gene. It is a sporadic missense mutation which has not been previously reported in the literature. It is caused by premature termination of protein translation and results in the production of truncated and non-functional proteins. This mutation is considered as a pathogenic variant and allows to broaden the spectrum of variants of TSC2 gene as a cause of TSC.

TSC1 and TSC2 gene mutations and their implications for treatment in Tuberous Sclerosis Complex: a review

Abstract Tuberous sclerosis complex is an autosomal dominant disorder characterized by skin manifestations and formation of multiple tumors in different organs, mainly in the central nervous system. Tuberous sclerosis is caused by the mutation of one of two tumor suppressor genes, TSC1 or TSC2. Currently, the development of novel techniques and great advances in high-throughput genetic analysis made mutation screening of the TSC1 and TSC2 genes more widely available. Extensive studies of the TSC1 and TSC2 genes in patients with TSC worldwide have revealed a wide spectrum of mutations. Consequently, the discovery of the underlying genetic defects in TSC has furthered our understanding of this complex genetic disorder, and genotype-phenotype correlations are becoming possible, although there are still only a few clearly established correlations. This review focuses on the main symptoms and genetic alterations described in TSC patients from 13 countries in three continents, as well as on genotype-phenotype correlations established to date. The determination of genotype-phenotype correlations may contribute to the establishment of successful personalized treatment for TSC.

The Challenge of Diagnosis and Indication for Treatment in Fabry Disease

Abstract Fabry disease, caused by deficient alpha-galactosidase A lysosomal enzyme activity, remains challenging to health-care professionals. Laboratory diagnosis in males is carried out by determination of alpha-galactosidase A activity; for females, enzymatic activity determination fails to detect the disease in about two-thirds of the patients, and only the identification of a pathogenic mutation in the GLA gene allows for a definite diagnosis. The hurdle to be overcome in this field is to determine whether a mutation that has never been described determines a ''classic'' or ''nonclassic'' phenotype, because this will have an impact on the decision-making for treatment initiation. Besides the enzymatic determination and GLA gene mutation determination, researchers are still searching for a good biomarker, and it seems that plasma lyso-Gb3 is a useful tool that correlates to the degree of substrate storage in organs. The ideal time for treatment initiation for children and nonclassic phenotype remains unclear.

Analysis of online Mendelian inheritance in man / 中国生化药物杂志

Objective To analyze the data from Online Mendelian Inheritance in Man (OMIM) to understand more about it, and provide reference to researchers using this database.Methods 19414 mutations which have definite relevant phenotypes from OMIM were obtained, then these mutations with three databases (1000 Genome Project,GO-ESP,ExAC) which record the mutation frequency in different population were compared.Results Most of the phenotype-related mutations from OMIM are rare mutations whose mutation frequency is less than 1%:18866 in 1000 Genome Project, 18981 in GO-ESP, 18979 in ExAC.The number of mutation whose frequency is more than 1% is 548433435 in 1000 Genome Project, GO-ESP, ExAC, respectively.And there are 320 mutations whose frequency is more than 1% in all databases.In all phenotypes, there are 127 polymorphism phenotypes, 584 susceptibility phenotypes, while in 320 ( 1.6%) phenotypes with common mutations, there are 62 polymorphism phenotypes, 88 susceptibility phenotypes and occupies 48.8%, 15.1%, respectively.Conclusion Approximately 97.5% mutations in OMIM are rare mutations.Polymorphism and susceptibility enrich in common mutations, especially in the mutation whose frequency is more than 10%.

The evolution of opsins and color vision: connecting genotype to a complex phenotype / Conectando el genotipo a un fenotipo complejo: evolución de las opsinas y la visión a color

Dissecting the genetic basis of adaptive traits is key to our understanding of evolutionary processes. A major and essential step in the study of evolutionary genetics is drawing link between genotype and phenotype, which depends on the difficult process of defining the phenotype at different levels, from functional to organismal. Visual pigments are a key component of the visual system and their evolution could also provide important clues on the evolution of visual sensory system in response to sexual and natural selection. As a system in which genotype can be linked to phenotype, I will use visual pigments and color vision, particularly in birds, as a case of a complex phenotype. I aim to emphasize the difficulties in drawing the genotype-phenotype relationship for complex phenotypes and to highlight the challenges of doing so for color vision. The use of vision-based receiver models to quantify animal colors and patterns is increasingly important in many fields of evolutionary research, spanning studies of mate choice, predation, camouflage and sensory ecology. Given these models impact on evolution and ecology, it is important to provide other researchers with the opportunity to better understand animal vision and the corresponding advantages and limitations of these models.

Entender la base genética de los rasgos adaptativos es un paso crítico en el estudio de los procesos evolutivos. Para estudiar la conexión entre genotipo y fenotipo es importante definir el fenotipo a diferentes niveles: desde las proteínas que se construyen con base en un gen, hasta las características finales presentes en un organismo. Las opsinas y los fotopigmentos son elementos primordiales de la visión y entender cómo han evolucionado es fundamental en el estudio de la visión en los animales como un caracter derivado de selección natural o sexual. Este artículo se enfoca en este sistema, en el que se pueden conectar genotipo y fenotipo, como ejemplo de fenotipo complejo para ilustrar las dificultades de establecer una relación clara entre genotipo y fenotipo. Adicionalmente, este artículo tiene como objetivo discutir el funcionamiento del sistema de fotorrecepción, con énfasis particular en las aves, con el fin de enumerar varios factores que deben ser tenidos en cuenta para predecir cambios en la visión a partir del estudio de los fotopigmentos. Dado que los modelos basados en la visión de aves son cada vez más usados en diversas áreas de la biología evolutiva tales como: selección de pareja, depredación y camuflaje; se hace relevante entender los fundamentos y limitaciones de estos modelos. Por esta razón, en este artículo discuto los detalles y aspectos prácticos del uso de los modelos de visión existentes para aves, con el fin de facilitar su uso en futuras investigaciones en diversas áreas de evolución.

Novel mutations of the arylsulphatase B (ARSB) gene in Indian patients with mucopolysaccharidosis type VI.

Background & objectives: Mucopolysaccharidosis type VI (MPS VI) is a rare, autosomal recessive lysosomal storage disorder caused by deficient enzymatic activity of N-acetyl galactosamine-4-sulphatase resulting from mutations in the arylsulphatase B (ARSB) gene. The ARSB gene is located on chromosome 5q11-q13 and is composed of eight exons. More than hundred ARSB mutations have been reported so far, but the mutation spectrum of MPS VI in India is still unknown. Hence, the aim of the present study was to identify the mutational spectrum in patients with MPS VI in India and to study the genotype-phenotype association and functional outcomes of these mutations. Methods: Molecular characterization of the ARSB gene by Sanger sequencing was done for 15 patients (aged 15 months to 11 yr) who were enzymatically confirmed to have MPS VI. Age of onset, clinical progression and enzyme activity levels in each patient were studied to look for genotype-phenotype association. Haplotype analysis performed for unrelated patients with the recurring mutation W450C, was suggestive of a founder effect. Sequence and structural analyses of the ARSB protein using standard software were carried out to determine the impact of detected mutations on the function of the ARSB protein. Results: A total of 12 mutations were identified, of which nine were novel mutations namely, p.D53N, p.L98R, p.Y103SfsX9, p.W353X, p.H393R, p.F166fsX18, p.I220fsX5, p.W450L, and p.W450C, and three were known mutations (p.D54N, p.A237D and p.S320R). The nine novel sequence variants were confirmed not to be polymorphic variants by performing sequencing in 50 unaffected individuals from the same ethnic population. Interpretation & conclusions: Nine novel mutations were identified in MPS VI cases from India in the present study. The study also provides some insights into the genotype-phenotype association in MPS VI.