Identification of novel variants in retinitis pigmentosa genes by whole-exome sequencing

SUMMARY OBJECTIVE: Retinitis pigmentosa is an inherited degenerative disorder causing severe retinal dystrophy and visual impairment, mainly with onset in the first or second decades. The next-generation sequencing has become an efficient tool to identify disease-causing mutations in retinitis pigmentosa. The aim of this retrospective study was to investigate novel gene variants and evaluate the utility of whole-exome sequencing in patients with retinitis pigmentosa. METHODS: The medical records of 20 patients with retinitis pigmentosa at Eskişehir City Hospital between September 2019 and February 2022 were analyzed retrospectively. Peripheral venous blood was obtained, followed by the extraction of genomic DNAs. The medical and ophthalmic histories were collected, and ophthalmological examinations were performed. Whole-exome sequencing was performed to determine the genetic etiology of the patients. RESULTS: The proportion of genetically solved cases was 75% (15/20) in the patients with retinitis pigmentosa. Molecular genetic testing identified 13 biallelic and 4 monoallelic mutations in known retinitis pigmentosa genes, including 11 novel variants. According to in silico prediction tools, nine variants were predicted as pathogenic or possibly pathogenic. We identified six previously reported mutations to be associated with retinitis pigmentosa. The age of onset of the patients ranged from 3 to 19, with a mean age of onset of 11.6. All patients had a loss of central vision. CONCLUSION: As the first study of the application of whole-exome sequencing among patients with retinitis pigmentosa in a Turkish cohort, our results may contribute to the characterization of the spectrum of variants related to retinitis pigmentosa in the Turkish population. Future population-based studies will enable us to reveal the detailed genetic epidemiology of retinitis pigmentosa.

A novel mutation in PAX6 gene causing congenital iris coloboma with congenital cataract in a pedigree / 中华实验眼科杂志

Objective:To identify the pathogenic gene and inheritance pattern in a pedigree of congenital iris coloboma with congenital cataract.Methods:The method of pedigree investigation was adopted.A pedigree of congenital iris coloboma with congenital cataract was collected by Yunnan Disabled Rehabilitation Center and the 2nd Afliated Hospital of Kunming Medical University in February 2020.Ophthalmic examinations were carried out on the female proband, her parents, her children and her husband, and the clinical diagnosis was made.Genomic DNA was extracted from peripheral blood samples collected from the family members.The suspected pathogenic gene in the proband and her husband was screened by whole exome sequencing and was identified by bioinformatics analysis.The amino acid conservation was analyzed by UGENE software.The impact of the mutation on protein translation was predicted using MutationTaster software.The pathogenicity of the mutation was assessed according to the American College of Medical Genetics (ACMG) Standards and Guidelines.Pathogenic gene and mutations were verified by Sanger sequencing.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the 2nd Afliated Hospital of Kunming Medical University (No.PJ-2020-61).Written informed consent was obtained from each subject or custodian.Results:The proband showed large iris defects in both eyes with only a small amount of observable iris tissue in the periphery, lens cortical opacity and posterior capsule opacification, accompanied by nystagmus.A novel heterozygous frameshift variation c. 415dupA (p.R139fs) was located in exon 8 of PAX6 gene, and the variation was conservative across multiple species.The variation was in the highly conserved region of PAX6 gene and caused the dysfunction of PAX6 protein.The variation was graded as PVS1+ PM2+ PP1, a pathogenic variation, based on ACMG guidelines.The pedigree was consistent with co-segregation, indicating that the novel variation was pathogenic.The proband and her children were diagnosed, but her parents were phenotypically normal, in accordance with autosomal dominant inheritance. Conclusions:The novel frameshift variation c.415dupA (p.R139fs) on the exon 8 of PAX6 gene is responsible for congenital iris coloboma with congenital cataract in the pedigree.This is the first report of this novel variation in PAX6 gene.

Screening of pathogenic mutation in a family with Axenfeld-Rieger syndrome by whole exome sequencing / 中华实验眼科杂志

Objective:To identify disease-causing variation in a Chinese family with Axenfeld-Rieger syndrome (ARS) through the analysis of clinical symptoms and hereditary information.Methods:The method of pedigree investigation was adopted.A Chinese ARS family including 15 family members of 3 generations was recruited in the Second Affiliated Hospital of Harbin Medical University in 2018.There were 3 patients in the family.The family history and clinical data were collected.Ophthalmic and general examinations were carried out in all the members included.DNA and RNA were extracted from collected peripheral venous blood samples of 2-5 ml from each member.Whole exome sequencing was used to screen the variations in the proband.Suspected variations screened through searching population databases and bioinformatics analysis were verified by Sanger sequencing and real-time quantitative PCR.Conservation analysis and deleteriousness prediction of suspected variations were conducted.The pathogenecity of candidate rare variations were evaluated according to the American College of Medical Genetics and Genomics (ACMG) standards and guidelines.This study followed the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Second Affiliated Hospital of Harbin Medical University (No.KY2019-231).Written informed consent was obtained from each subject or custodian prior to entering the study cohort.Results:The 3 patients all had typical ARS clinical features in eyes, teeth and umbilicus, and carried the same heterozygous variant, c.525delC (p.Asp175Glufs *) in the PITX2 gene, which were not found in other members, indicating co-segregation.The relative expression of PITX2 mRNA was 0.672±0.063 in the patients, which was significantly lower than 1.015±0.179 in the healthy controls ( t=8.847, P<0.001).This variant was not recorded in dbSNP, 1000G, gnomeAD, ExAC, Korea1K and EVS databases, and it was labelled as deleterious by MutationTaster.The affected conservative amino acid sequences were found in 9 species.The variant was determined as pathogenic according to the ACMG standards and guidelines. Conclusions:The c.525delC (p.Asp175Glufs *) mutation of PITX2 gene is pathogenic in the pedigree.This is the first time that this mutation has been reported in Chinese family with ARS.

A novel mutation in the ALOX12B gene in hereditary ichthyosis: pedigree analysis for a female collodion baby / 中华皮肤科杂志

Objective:To investigate pathogenic genes and inheritance patterns in 3 consecutive collodion babies in a family.Methods:The proband was diagnosed as a collodion baby due to extensive dry and chapped skin all over the body at birth. Phenotypes of the proband's parents were normal, but their first and second children presented with dry and chapped skin at birth and died a few days after birth. DNA was extracted from peripheral blood samples of the patient and her parents for whole-exome capture sequencing, and candidate mutations were verified by Sanger sequencing.Results:Compound heterozygous mutations in the ALOX12B gene were identified in the infant, including a missense mutation c.1405 C>T (p.R469w) inherited from her father and a frameshift mutation c.68_69insC (p.L24fs) inherited from her mother.Conclusions:The infant was diagnosed with hereditary ichthyosis, which was inherited in an autosomal recessive manner. The missense mutation c.1405 C>T and frameshift mutation c.68_69insC in the ALOX12B gene may contribute to the clinical phenotype of this infant, and the frameshift mutation had not been reported in China or other countries.

Wiedemann-Steiner syndrome with a novel pathogenic variant in KMT2A: a case report / Síndrome de Wiedemann-Steiner por una nueva variante patogénica en KMT2A: reporte de un caso

Abstract Case Description: We report the case of a one-year-old girl who was diagnosed with Wiedemann-Steiner Syndrome based on the identification of a novel de novo frameshift mutation in the KMT2A gene by whole exome sequencing and supported by her clinical features. Clinical Findings: KMT2A mutations cause Wiedemann-Steiner Syndrome, a very rare genetic disorder characterized by congenital hypertrichosis, short stature, intellectual disability, and distinct facial features. Treatment and Outcome: Whole exome sequencing identified a novel frameshift variant: c. 4177dupA (p.Ile1393Asnfs * 14) in KMT2A; this change generates an alteration of the specific binding to non-methylated CpG motifs of the DNA to the protein. The genotype and phenotype of the patient were compared with those of earlier reported patients in the literature. Clinical Relevance: In diseases with low frequency, it is necessary to establish a genotype-phenotype correlation that allows the establishment of therapeutic and follow-up goals. The phenotype comparation with other reported cases did not show differences attributable to sex or age among patients with Wiedemann-Steiner Syndrome. Whole exome sequencing allows identifying causality in conditions with high clinical and genetic heterogeneity like hypertrichosis.

Resumen Descripción del caso: Se reporta el caso de una paciente femenina de un año de edad, diagnosticada con Síndrome de Wiedemann-Steiner basado en la identificación de una nueva variante patogénica de novo de tipo frameshift en el gen KMT2A Mediante secuenciación de exoma usando el enfoque de trio, sumado a sus características clínicas. Hallazgos clínicos: las mutaciones en KMT2A causan el Síndrome de Wiedemann-Steiner, un desorden genético muy raro caracterizado por hipertricosis congénita, talla baja, retardo mental variable y fenotipo facial distintivo, los cuales se encuentran en la paciente reportada. Resultado: La Secuenciación de exoma completo encontró una variante de tipo frameshift: c.4177dupA (p. Ile1393Asnfs * 14) en KMT2A, este cambio a nivel génico genera una alteración de la unión específica a motivos CpG no metilados del DNA a la proteína. El genotipo y el fenotipo de la paciente fue comparado con los pacientes reportados previamente en la literatura. Relevancia clínica: En enfermedades con baja frecuencia como la aquí reportada es necesario establecer correlaciones genotipo-fenotipo que permitan establecer planes terapéuticos y de seguimiento. El análisis realizado no evidenció diferencias atribuibles a sexo o edad entre los pacientes diagnosticados con Síndrome de Weidemann-Steiner. La secuenciación de exoma permitió identificar causalidad en este caso, cuya característica principal de hipertricosis se asocia con alta heterogeneidad clínica y genética.

A Novel RUNX2 Mutation in a Korean Family with Cleidocranial Dysplasia / 대한소아치과학회지

Cleidocranial dysplasia (CCD) is an autosomal-dominant disease characterized by the delayed closure of cranial sutures, defects in clavicle formation, supernumerary teeth, and delayed tooth eruption. Defects in the Runt-related transcription factor 2 (RUNX2), a master regulator of bone formation, have been identified in CCD patients. The aim of this study was to identify the molecular genetic causes in a CCD family with delayed tooth eruption.The 23-year-old female proband and her mother underwent clinical and radiographic examinations, and all coding exons of the RUNX2 were sequenced. Mutational analysis revealed a single nucleotide deletion mutation (NM_001024630.4 : c.357delC) in exon 3 in the proband and her mother. The single C deletion would result in a frameshift in translation and introduce a premature stop codon [p.(Asn120Thrfs*24)]. This would result in the impaired function of RUNX2 protein, which may be the cause of delayed eruption of permanent teeth in the family.

Genetic Analysis of A Familial Adenomatous Polyposis Pedigree / 胃肠病学

Background: The adenomatous polyposis coli (APC) gene mutation is closely related to the risk of familial adenomatous polyposis (FAP). Aims: To analyze the genetic etiology of a FAP pedigree. Methods: FAP was diagnosed in a patient with repeated hematochezia after the receiving of endoscopy, pathological analysis and family history investigation. Genetic analysis was conducted by new-generation sequencing (NGS) technique in the FAP family members. Results: A heterozygous mutation of APC gene c.2800_2803delACTT (p.T934fs) was existed in the family members, which led to the frame shifts of APC gene and resulted in the change of encoding amino acids sequence and formed the abnormal proteins. This mutation could lead to serious FAP symptoms with early onset of colorectal adenoma and carcinogenesis. Conclusions: NGS can diagnose the disease much earlier and more accurately, and provide a new detection method for the early prevention of genetic diseases. The heterozygous mutation of p.T934fs is the root etiology of the clinical phenotype of this FAP pedigree, and polypectomy should be considered in affected members for preventing the carcinogenesis of colon.

Founder Mutations for Early Onset Melanoma as Revealed by Whole Exome Sequencing Suggests That This is Not Associated with the Increasing Incidence of Melanoma in Poland / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Germline mutations within melanoma susceptibility genes are present only in minority of melanoma patients and it is expected that additional genes will be discovered with next generation sequence technology and whole-exome sequencing (WES). MATERIALS AND METHODS: Herein we performed WES on a cohort of 96 unrelated Polish patients with melanoma diagnosed under the age of 40 years who all screened negative for the presence of CDKN2A variants. A replication study using a set of 1,200 melanoma patient DNA samples and similarly large series of healthy controls was undertaken. RESULTS: We selected 21 potentially deleterious variants in 20 genes (VRK1, MYCT1, DNAH14, CASC3, MS4A12, PRC1, WWOX, CARD6, EXO5, CASC3, CASP8AP2, STK33, SAMD11, CNDP2, CPNE1, EFCAB6, CABLES1, LEKR1, NUDT17, and RRP15), which were identified by WES and confirmed by Sanger sequencing for an association study. Evaluation of the allele distribution among carriers and their relatives in available family trios revealed that these variants were unlikely to account for many familial cases of melanoma. Replication study revealed no statistically significant differences between cases and controls. CONCLUSION: Although most of the changes seemed to be neutral we could not exclude an association between variants in VRK1, CREB3L3, EXO5, and STK33 with melanoma risk.

Two Compound Heterozygous Were Identified in SLC26A4 Gene in Two Chinese Families With Enlarged Vestibular Aqueduct

OBJECTIVES: To investigate the genetic causes of hearing loss with enlarged vestibular aqueduct (EVA) in two children from unrelated two Chinese families. METHODS: Sanger sequencing of all coding exons in SLC26A4 (encoding Pendrin protein) was performed on the two patients, their sibling and parents respectively. To predict and visualize the potential functional outcome of the novel variant, model building, structure analysis, and in silico analysis were further conducted. RESULTS: The results showed that the proband from family I harbored a compound heterozygote of SLC26A4 c.1174A>T (p.N392Y) mutation and c.1181delTCT (p.F394del) variant in exon 10, potentially altering Pendrin protein structure. In family II, the proband was identified in compound heterozygosity with a known mutation of c.919-2A>G in the splice site of intron 7 and a novel mutation of c.1023insC in exon 9, which results in a frameshift and translational termination, consequently leading to truncated Pendrin protein. Sequence homology analysis indicated that all the mutations localized at high conservation sites, which emphasized the significance of these mutations on Pendrin spatial organization and function. CONCLUSION: In summary, this study revealed two compound heterozygous mutations (c.1174A>T/c.1181delTCT; c.919- 2A>G/c.1023insC) in Pendrin protein, which might account for the deafness of the two probands clinically diagnosed with EVA. Thus this study contributes to improve understanding of the causes of hearing loss associated with EVA and develop a more scientific screening strategy for deafness.

Case of D-Variant from a Frameshift Mutation RHD 711delC / 대한수혈학회지

D antigens are clinically significant, and routine tests on the D antigen requires the inclusion of weak D testing, which is performed using indirect antihuman immunoglobulin methods. On the other hand, exact typing of the D type of an individual can be done more precisely with RHD genotyping, which is a useful tool in cases where the RHD gene is intact. The majority of weak-D or partial-D cases are from single nucleotide changes or hybridization of RHD and RHCE genes. Nevertheless, frameshift mutations can also result in weak or partial-D. The characteristics of a frameshift mutation is typically a change in protein product after a problematic mutation and early termination of transcription, leading into truncated protein products. This paper reports a D-variant case with RHD 711delC along with a review of the relevant literature. In addition, the results of software analysis are reported.

Gene identification in a family of hereditary hemorrhagic telangiectasia / 中华血液学杂志

Objective@#To study the mutation of ENG, ACVRL1, and SMAD4 genes in one of a family of hereditary hemorrhagic telangiectasia (HHT) and explore its molecular pathogenesis. @*Methods@#A family spectrum of a patient with a clinical diagnosis of HHT was surveyed. Peripheral blood samples from proband and their eldest were collected, and ENG, ACVRL1 and SMAD4 gene analysis was performed by chip capture high-throughput sequencing. The mutation detected was verified by Sanger. @*Results@#9 of the 71 family members were diagnosed with HHT with the main manifestation of recurrent nasal bleeding. Genetic analysis showed that the proband and the eldest son of ENG gene exon 9 frameshift mutation: c.1502-1503insGG (p.Gly501GlyfsX18) , and mutations in ACVRL1 and SMAD4 genes were not detected. @*Conclusion@#The frameshift mutation c.1502-1503insGG (p.Gly501GlyfsX18) of the ENG gene is the genetic basis for the pathogenesis of this HHT family.

Detection and analysis of gene mutation in a case of child's renal coloboma syndrome / 中华眼底病杂志

Objective To analyze and identify the pathogenic mutation that caused a case of child's renal coloboma syndrome (RCS).Methods A child with congenital cataract in the right eye and optic disc defect in the left eye and his parents with normal phenotype were included in the study.The blood of the child and his parents were captured to extract DNA and make molecular test.The possible variants were screened through NGS sequencing using the ophthalmology gene panel on illumina NextSeq 500 platform,and proved the selected PAX2 mutation by Sanger sequencing.Pathogenicity report was retrieved through PubMed and related database.Pathogenicity analysis of the candidate mutated site has careful consideration of the patient's clinical presentations and sequencing result base on Standards and Guidelines for the Interpretation of Sequence Variants revised by ACMG.According to the results of gene diagnosis,the child was executed related clinical examinations on kidney.Results The sequence result showed that a heterozygous mutation in PAX2,c.70dupG (p.V26Gfs*28),which lead to truncated protein product that terminated after 28 amino acids of the mutated site.Both of his normal parents were not carriers of the heterozygous mutation.Sanger sequencing results of the child and his parents were consistent with the NGS sequencing.The autosomal dominant disease phenotype was inferred to be caused by the heterozygous mutation of c.70dupG (p.V26Gfs*28) of PAX2 gene.Renal color Doppler ultrasound results showed the child with small renal cysts on the left and mildly separated collecting system.Renal function tests showed the child with αl microglobulin index increased.Conclusion The heterozygous mutation c.70dupG (p.V26Gfs*28) in PAX2 is the genetic pathogenic cause for the patient with RCS.

Genetic analysis of a family with Usher syndrome / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To analyze the clinical features of a Usher syndrome family and explore the pathogenic gene of the disease. <p>METHODS: A Chinese family with Usher syndrome was involved in our study. After informed consent, careful clinical examinations were taken and 4mL blood were obtained. The whole genome DNA was extracted and target-captured next generation sequencing of the proband was performed to identify suspected mutations. We used Sanger sequencing to verify the detected mutations in all the members of the family, as well as in 100 normal controls. <p>RESULTS: In addition to typical retinitis pigmentosa, the patients suffered from mild to moderate sensorineural deafness. Sequencing results revealed compound heterozygous mutations(c.2310_2311insA and c.8559-2A>G)of <i>USH2A</i> gene in the patients, and either of the mutations was found in normal relatives that had consanguinity with the patients. Both of the mutations were not found in other members of the family and normal individuals. <p>CONCLUSION: <i>USH2A</i> is the pathogenic gene of the disease in this family. The mutation c.8559-2A>G(IVS42)is a previously reported mutation, while the mutation c.2310_2311 insA(p.E771Rfs*8)is a novel mutation. The study has expanded the mutation spectrum of <i>USH2A</i> gene resulting in Usher syndrome.

A novel PAX6 mutation in a Chinese family with congenital aniridia / 中华实验眼科杂志

Background Aniridia is a rare congenital hereditary eye disease.Studies determined that PAX6 gene mutation is closely associated with congenital aniridia,but the mutation locus are varied.Objective This study was to identify virulence mutation locus of PAX6 gene of a Chinese family pedigree with autosomal dominant aniridia.Methods A Chinese family affected with autosomal dominant aniridia was collected and examined in Affiliated First Hospital of Zhengzhou University in August 2014.Periphery blood of 10 ml was collected from all the families and 100 unrelated health controls.The genomic DNA was extracted by standardized phenol-chloroform method,and all exons and splicing junctions of PAX6 were amplified by PCR.Real-time fluorescence quantitative PCR was performed to examine the relative expression of PAX6 mRNA in patients and normal phenotype families and heahh controls.This study protocol was approved by Ethic Committee of Affiliated First Hospital of Zhengzhou University and complied with Helsinki Declaration.Written informed consent was obtained from subjects or custodian before any medical examination.Results This Chinese family inclued 3 generations and 9 members,with a classic autosomal dominant inheritance mode.Five patients were found,showing the absence of iris and cataract in 3 adult patients and only absence of the iris in 2 children,and other 4 members showed the normal phenotype.A novel heterozygous PAX6 deletion mutation c.796 del G (p.A266 fs) (GenBank ID:KP255960) in exon 10 was exclusively found in all affected individuals but not in any of the unaffected families or unrelated health controls.PAX6 mRNA level in lymphocytes was about 50％ lower in aniridia patients than in unaffected family members,indicating that this mutation caused nonsense-mediated mRNA decay.Conclusions A novel deletion mutation in PAX6 gene results in an abnormal PAX6 COOH-terminal extension in the Chinese aniridia family.This finding expands the mutation spectrum of PAX6 gene.

Birt-Hogg-Dubé syndrome / Sindrome de Birt-Hogg-Dube

A 45-year-old woman with a history of renal carcinoma was observed for facial, cervical and truncal flesh-colored papules. Relatives had similar skin findings and a brother had repeated episodes of pneumothorax. The computerized tomography scan revealed multiple cysts on both lungs. A skin biopsy revealed a perifollicular fibroma. The clinical diagnosis of Birt-Hogg-Dubé syndrome (BHDS) was corroborated by identification of a novel frameshift c.573delGAinsT (p.G191fsX31) mutation in heterozygosity on exon 6 of the folliculin gene. The presence of multiple and typical benign hair follicle tumors highlights the role of the dermatologist in the diagnosis of this rare genodermatosis that is associated with an increased risk of renal cell cancer and pulmonary cysts, warranting personal and familial follow-up and counseling.

Uma mulher de 45 anos com história de carcinoma renal foi observada por pápulas cor da pele, faciais, cervicais e tronculares. Referia história familiar de achados cutâneos semelhantes e irmão com episódios repetidos de pneumotórax. Identificaram-se múltiplos quistos pulmonares por tomografia computorizada. Uma biópsia cutânea revelou fibroma perifolicular. O diagnóstico clínico de síndrome de Birt-Hogg-Dubé (BHDS) foi contudo corroborado pela identificação de uma nova mutação frameshift c.573delGAinsT (p.G191fsX31) em heterozigotia no exão 6 do gene da foliculina. A presença de múltiplos e típicos tumores benignos do folículo piloso, realça o papel do dermatologista no diagnóstico desta rara genodermatose, que está associada a um risco aumentado de tumores de células renais e cistos pulmonares, exigindo seguimento e aconselhamento pessoal e familiar.

A Novel Frameshift Mutation of the USH2A Gene in a Korean Patient with Usher Syndrome Type II

Usher syndrome type II (USH2) is the most common form of Usher syndrome, characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa. It has been shown that mutations in the USH2A gene are responsible for USH2. The authors herein describe a 34-year-old Korean woman with the typical clinical manifestation of USH2; she had bilateral hearing disturbance and progressive visual deterioration, without vestibular dysfunction. Molecular genetic study of the USH2A gene revealed a novel frameshift mutation (c.2310delA; Glu771LysfsX17). She was heterozygous for this mutation, and no other mutation was found in USH2A, suggesting the possibility of an intronic or large genomic rearrangement mutation. To the best of our knowledge, this is the first report of a genetically confirmed case of USH2 in Korea. More investigations are needed to delineate genotype-phenotype correlations and ethnicity-specific genetic background of Usher syndrome.

Single Nucleotide Deletion Mutation of KCNH2 Gene is Responsible for LQT Syndrome in a 3-Generation Korean Family

Long QT syndrome (LQTS) is characterized by the prolongation of the QT interval in ECG and manifests predisposition to life threatening arrhythmia which often leads to sudden cardiac death. We encountered a 3-generation family with 5 affected family members in which LQTS was inherited in autosomal dominant manner. The LQTS is considered an ion channel disorder in which the type and location of the genetic mutation determines to a large extent the expression of the clinical syndrome. Upon screening of the genomic sequences of cardiac potassium ion channel genes, we found a single nucleotide C deletion mutation in the exon 3 of KCNH2 gene that co-segregates with the LQTS in this family. This mutation presumably resulted in a frameshift mutation, P151fs+15X. This study added a new genetic cause to the pool of mutations that lead to defected potassium ion channels in the heart.

A Novel PA-X Protein Translated from Influenza A Virus Segment 3

The pathogenicity of influenza A viruses is a multigenic trait, which is orchestrated by the global networks between eight viral genomic constituents and their cellular interacting partners. A recent report provided information on the finding of a new PA ribosomal frameshifting product, the PA-X protein, in the influenza A virus segment 3, and an endonuclease property was suggested for a possible role of the PA-X protein. In cultured cells, viral growth was not affected by the PA-X protein expression. However, the reduced pathogenicity of mice appeared to be closely associated with the PA-X protein expression. It was also revealed that the PA-X protein was able to modulate host gene expression. Considered together, the PA-X protein can be a cellular signaling modulator and subsequently control viral pathogenicity. By reviewing recent publications, we present new insights in the contribution of the PA-X protein to the cellular signaling network and the resultant viral pathogenicity.

A novel mutation (4040-4045 nt. delA) in exon 14 of the factor VIII gene causing severe hemophilia A.

Hemophilia A is an X-linked congenital bleeding disorder caused by Factor VIII deficiency. Different mutations including point mutations, deletions, insertions and inversions have been reported in the FVIII gene, which cause hemophilia A. In the current study, with the use of conformational sensitive gel electrophoresis (CSGE) analysis, we report a novel 1-nt deletion in the A6 sequence at codons 1328-1330 (4040-4045 nt delA) occurring in exon 14 of the FVIII gene in a seven-year-old Iranian boy with severe hemophilia A. This mutation that causes frameshift and premature stop-codon at 1331 has not previously been reported in the F8 Hemophilia A Mutation, Structure, Test and Resource Site (HAMSTeRS) database.

Identification of a novel mutation in DAX1/NR0B1A gene in two siblings with severe clinical presentation of adrenal hypoplasia congenita / Identificação de nova mutação no gene DAX1/NR0B1A em dois irmãos com forma clínica grave de hipoplasia adrenal congênita

OBJECTIVE: To search for mutations in DAX1/NR0B1A gene in siblings to establish the molecular etiology of the adrenal hypoplasia congenita (AHC), a rare potentially life-threatening disorder. CASE REPORT: We describe two siblings who presented with salt-wasting syndrome in the newborn period and received hormonal replacement for primary adrenal insufficiency. A diagnostic hypothesis of AHC was suspected because the children maintained, during hormonal treatment, low plasma 17-OH progesterone (17-OHP) and androgens, despite high ACTH levels. RESULTS: DAX1 gene was studied by molecular analysis, which showed a mutation, confirming the diagnosis in the siblings and a heterozygous state in the mother. Direct sequencing of DAX1 revealed an insertion of an adenine base (c1382-1383 A ins), which lead to a pMet461Asp substitution. CONCLUSION: A novel frameshift mutation of DAX1 gene, which established the molecular etiology of the AHC in the siblings, was identified. Obtaining a precise genetic diagnosis of this adrenal disorder, which, sometimes, cannot be confirmed only by clinical aspects, may have important implications for the long-term management of the disease.

OBJETIVO: Pesquisar mutações no gene DAX1/NR0B1A em dois irmãos com suspeita de hipoplasia adrenal congênita (HAC), rara doença potencialmente fatal, para estabelecer sua etiologia molecular. RELATO DOS CASOS: São apresentados os relatos de dois irmãos com síndrome perdedora de sal no período neonatal que receberam terapia de reposição hormonal para insuficiência adrenal primária. O diagnóstico de HAC foi suspeitado porque as crianças mantiveram, durante o tratamento hormonal, níveis plasmáticos reduzidos de 17-OH-progesterona e andrógenos ao lado de níveis elevados de ACTH. RESULTADOS: A análise molecular do gene DAX1 mostrou a mutação, confirmando o diagnóstico nos irmãos e o estado heterozigoto da mãe. No sequenciamento direto do DAX1 foi encontrada inserção de uma adenina (c1382-1383 A ins), levando à substituição pMet461Asp. CONCLUSÃO: Uma nova mutação da fase de leitura no gene DAX1 foi identificada, estabelecendo a etiologia molecular da HAC nos dois irmãos. Um diagnóstico genético preciso deste distúrbio adrenal, frequentemente não confirmado apenas pelos aspectos clínicos, pode ter importantes implicações para o manuseio em longo prazo da doença.