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3. Biallelic loss of human CTNNA2, encoding αN-catenin, leads to ARP2/3 complex overactivity and disordered cortical neuronal migration.

Author

Schaffer, Ashleigh E, Breuss, Martin W, Caglayan, Ahmet Okay, Al-Sanaa, Nouriya, Al-Abdulwahed, Hind Y, Kaymakçalan, Hande, Yılmaz, Cahide, Zaki, Maha S, Rosti, Rasim O, Copeland, Brett, Baek, Seung Tae, Musaev, Damir, Scott, Eric C, Ben-Omran, Tawfeg, Kariminejad, Ariana, Kayserili, Hulya, Mojahedi, Faezeh, Kara, Majdi, Cai, Na, Silhavy, Jennifer L, Elsharif, Seham, Fenercioglu, Elif, Barshop, Bruce A, Kara, Bulent, Wang, Rengang, Stanley, Valentina, James, Kiely N, Nachnani, Rahul, Kalur, Aneesha, Megahed, Hisham, Incecik, Faruk, Danda, Sumita, Alanay, Yasemin, Faqeih, Eissa, Melikishvili, Gia, Mansour, Lobna, Miller, Ian, Sukhudyan, Biayna, Chelly, Jamel, Dobyns, William B, Bilguvar, Kaya, Jamra, Rami Abou, Gunel, Murat, and Gleeson, Joseph G

Subjects
Cerebral Cortex, Neurons, Animals, Mice, Inbred C57BL, Humans, Mice, Nerve Tissue Proteins, Pedigree, Cell Movement, Mutation, Genome, Human, alpha Catenin, Actin-Related Protein 2-3 Complex, Embryo, Mammalian, Neurosciences, Rare Diseases, Clinical Research, 2.1 Biological and endogenous factors, Neurological, Developmental Biology, Biological Sciences, Medical and Health Sciences
Abstract

Neuronal migration defects, including pachygyria, are among the most severe developmental brain defects in humans. Here, we identify biallelic truncating mutations in CTNNA2, encoding αN-catenin, in patients with a distinct recessive form of pachygyria. CTNNA2 was expressed in human cerebral cortex, and its loss in neurons led to defects in neurite stability and migration. The αN-catenin paralog, αE-catenin, acts as a switch regulating the balance between β-catenin and Arp2/3 actin filament activities1. Loss of αN-catenin did not affect β-catenin signaling, but recombinant αN-catenin interacted with purified actin and repressed ARP2/3 actin-branching activity. The actin-binding domain of αN-catenin or ARP2/3 inhibitors rescued the neuronal phenotype associated with CTNNA2 loss, suggesting ARP2/3 de-repression as a potential disease mechanism. Our findings identify CTNNA2 as the first catenin family member with biallelic mutations in humans, causing a new pachygyria syndrome linked to actin regulation, and uncover a key factor involved in ARP2/3 repression in neurons.

Published
2018

4. Inherited glycosylphosphatidylinositol defects cause the rare Emm-negative blood phenotype and developmental disorders

Author

Duval, Romain, Nicolas, Gaël, Willemetz, Alexandra, Murakami, Yoshiko, Mikdar, Mahmoud, Vrignaud, Cedric, Megahed, Hisham, Cartron, Jean-Pierre, Masson, Cecile, Wehbi, Samer, Koehl, Bérengere, Hully, Marie, Siquier, Karine, Chemlay, Nicole, Rotig, Agnes, Lyonnet, Stanislas, Colin, Yves, Barcia, Giulia, Cantagrel, Vincent, Le Van Kim, Caroline, Hermine, Olivier, Kinoshita, Taroh, Peyrard, Thierry, and Azouzi, Slim

Published
2021
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6. Wnt/Wg pathway activation in medulloblastoma and disease risk stratification

Author

Megahed, Hisham

Subjects
618.92
Abstract

Despite improvements in the diagnosis and therapy of medulloblastoma (MB), the most common malignant paediatric brain tumour, survival rates are still only 40-60% for high-risk patients, and surviving patients offer suffer life-long therapy-associated late effects. Improving the current clinical disease risk classification may provide opportunities to tailor therapy to disease-risk more accurately, aiming to improve survival whilst minimizing late effects. The overall aim of this study was to identify and validate clinicopathological and molecular markers of prognostic significance in a large cohort of cases derived from the PNET3 clinical trial, which could be used in improved disease stratification schemes. Initial investigations focussed on defects of chromosome 17, the most common chromosomal aberrations identified in MB, which have been associated with adverse outcome in some previous studies. During this initial study, methods for testing for regions of genetic loss in DNA samples extracted from routinely collected and stored pathology material were developed and validated. Using these methods, 17p loss was assessed in 284 cases overall, but did not show an association with poor prognosis. 17p loss was rare in patients <3 years at diagnosis (1/21 cases) compared to children aged >3 years (21/59, p=0.009), supporting the notion that infants with MB may represent a biologically distinct disease subgroup. During the course of this study, evidence of a microsatellite instability phenotype was also found in one case (1/29; 3.8%), suggesting a role for this phenomenon in a small subset of medulloblastomas. Previous studies have identified MBs with activation of the Wnt/Wg signalling pathway to be associated with a favourable outcome. Three independent molecular markers of Wnt/Wg activation in medulloblastoma (β-catenin nuclear localization, CTNNB1 mutation and chromosome 6 loss) have recently been identified, and were therefore assessed in the PNET3 cohort to examine their inter-relationships and relative prognostic utilities. β-catenin nuclear localization was detected in 34/207 (16.4%) cases, CTNNB1 mutation in 20/197 (10.1%), and chromosome 6 LOH in 20/190 (10.5%); all three markers were highly associated with each other (p=0.001). Univariate survival analysis showed significant associations between clinicopathological (gender, pathology, M stage and extent of tumour resection) and molecular variables (β-catenin nuclear localization and CTNNB1 mutation) with survival (all 'p' values <0.03) in the PNET3 cohort. Multivariate survival analysis and Cox proportional regression hazard analysis identified M stage, large cell / anaplastic pathology, gender and β-catenin nuclear staining to be significantly associated with prognosis (p<0.04), with hazard ratios of 1.924, 3.338, 0.57 and 0.215, respectively. Finally, combined models for disease risk prediction were constructed using the prognostically significant clinicopathological and molecular variables identified, including models to precisely classify the overall disease hazard for individual cases based on their clinical, pathological and molecular profile. In summary, Wnt/Wg pathway activation was associated with favourable outcome and can be most accurately identified using β-catenin nuclear staining. Combined models which incorporate Wnt/Wg status alongside other prognostically significant clinical and pathological indices validated in this study provide schemes for improved disease risk prediction in medulloblastoma, which should now be tested prospectively in large clinical trials.

Published
2010

8. Supplementary Data from Rapid Diagnosis of Medulloblastoma Molecular Subgroups

Author

Schwalbe, Ed C., primary, Lindsey, Janet C., primary, Straughton, Debbie, primary, Hogg, Twala L., primary, Cole, Michael, primary, Megahed, Hisham, primary, Ryan, Sarra L., primary, Lusher, Meryl E., primary, Taylor, Michael D., primary, Gilbertson, Richard J., primary, Ellison, David W., primary, Bailey, Simon, primary, and Clifford, Steven C., primary

Published
2023
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9. Exome Sequencing Links Corticospinal Motor Neuron Disease to Common Neurodegenerative Disorders

Author

Novarino, Gaia, Fenstermaker, Ali G., Zaki, Maha S., Hofree, Matan, Silhavy, Jennifer L., Heiberg, Andrew D., Abdellateef, Mostafa, Rosti, Basak, Scott, Eric, Mansour, Lobna, Masri, Amira, Kayserili, Hulya, Al-Aama, Jumana Y., Abdel-Salam, Ghada M. H., Karminejad, Ariana, Kara, Majdi, Kara, Bulent, Bozorgmehri, Bita, Ben-Omran, Tawfeg, Mojahedi, Faezeh, Mahmoud, Iman Gamal El Din, Bouslam, Naima, Bouhouche, Ahmed, Benomar, Ali, Hanein, Sylvain, Raymond, Laure, Forlani, Sylvie, Mascaro, Massimo, Selim, Laila, Shehata, Nabil, Al-Allawi, Nasir, Bindu, P.S., Azam, Matloob, Gunel, Murat, Caglayan, Ahmet, Bilguvar, Kaya, Tolun, Aslihan, Issa, Mahmoud Y., Schroth, Jana, Spencer, Emily G., Rosti, Rasim O., Akizu, Naiara, Vaux, Keith K., Johansen, Anide, Koh, Alice A., Megahed, Hisham, Durr, Alexandra, Brice, Alexis, Stevanin, Giovanni, Gabriel, Stacy B., Ideker, Trey, and Gleeson, Joseph G.

Published
2014

12. Biallelic loss of EMC10 leads to mild to severe intellectual disability

Author

Kaiyrzhanov, Rauan, primary, Rocca, Clarissa, additional, Suri, Mohnish, additional, Gulieva, Sughra, additional, Zaki, Maha S., additional, Henig, Noa Z., additional, Siquier, Karine, additional, Guliyeva, Ulviyya, additional, Mounir, Samir M., additional, Marom, Daphna, additional, Allahverdiyeva, Aynur, additional, Megahed, Hisham, additional, van Bokhoven, Hans, additional, Cantagrel, Vincent, additional, Rad, Aboulfazl, additional, Pourkeramti, Alemeh, additional, Dehghani, Boshra, additional, Shao, Diane D., additional, Markus‐Bustani, Keren, additional, Sofrin‐Drucker, Efrat, additional, Orenstein, Naama, additional, Salayev, Kamran, additional, Arrigoni, Filippo, additional, Houlden, Henry, additional, and Maroofian, Reza, additional

Published
2022
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14. Emm : un nouveau système de groupe sanguin associé à des troubles neurodéveloppementaux

Author

Duval, Romain, primary, Nicolas, Gael, additional, Willemetz, Alexandra, additional, Murakami, Yoshiko, additional, Mikdar, Mahmoud, additional, Vrignaud, Cedric, additional, Megahed, Hisham, additional, Cartron, Jean-Pierre, additional, Masson, Cecile, additional, Wehbi, Samer, additional, Koehl, Bérengere, additional, Hully, Marie, additional, Siquier, Karine, additional, Chemlay, Nicole, additional, Rotig, Agnes, additional, Lyonnet, Stanislas, additional, Colin, Yves, additional, Barcia, Giulia, additional, Cantagrel, Vincent, additional, Le Van Kim, Caroline, additional, Hermine, Olivier, additional, Kinoshita, Taroh, additional, Peyrard, Thierry, additional, and Azouzi, Slim, additional

Published
2021
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16. MYC family amplification and clinical risk-factors interact to predict an extremely poor prognosis in childhood medulloblastoma

Author

Ryan, Sarra L., Schwalbe, Ed C., Cole, Michael, Lu, Yuan, Lusher, Meryl E., Megahed, Hisham, O’Toole, Kieran, Nicholson, Sarah Leigh, Bognar, Laszlo, Garami, Miklos, Hauser, Peter, Korshunov, Andrey, Pfister, Stefan M., Williamson, Daniel, Taylor, Roger E., Ellison, David W., Bailey, Simon, and Clifford, Steven C.

Published
2012
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20. Clinical and genetic characterization of ten Egyptian patients with Wolf–Hirschhorn syndrome and review of literature

Author

Mekkawy, Mona K., primary, Kamel, Alaa K., additional, Thomas, Manal M., additional, Ashaat, Engy A., additional, Zaki, Maha S., additional, Eid, Ola M., additional, Ismail, Samira, additional, Hammad, Saida A., additional, Megahed, Hisham, additional, ElAwady, Heba, additional, Refaat, Khaled M., additional, Hussien, Shymaa, additional, Helmy, Nivine, additional, Abd Allah, Sally G., additional, Mohamed, Amal M., additional, and El Ruby, Mona O., additional

Published
2020
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22. Clinical and genetic characterization of ten Egyptian patients with Wolf–Hirschhorn syndrome and review of literature.

Author

Mekkawy, Mona K., Kamel, Alaa K., Thomas, Manal M., Ashaat, Engy A., Zaki, Maha S., Eid, Ola M., Ismail, Samira, Hammad, Saida A., Megahed, Hisham, ElAwady, Heba, Refaat, Khaled M., Hussien, Shymaa, Helmy, Nivine, Abd Allah, Sally G., Mohamed, Amal M., and El Ruby, Mona O.

Subjects
SYNDROMES, KARYOTYPES, INTELLECTUAL disabilities, CONGENITAL disorders
Abstract

Background: Wolf–Hirschhorn syndrome (WHS) (OMIM 194190) is a multiple congenital anomalies/intellectual disability syndrome. It is caused by partial loss of genetic material from the distal portion of the short arm of chromosome. Methods: We studied the phenotype–genotype correlation. Results: We present the clinical manifestations and cytogenetic results of 10 unrelated Egyptian patients with 4p deletions. Karyotyping, FISH and MLPA was performed for screening for microdeletion syndromes. Array CGH was done for two patients. All patients exhibited the cardinal clinical manifestation of WHS. FISH proved deletion of the specific WHS locus in all patients. MLPA detected microdeletion of the specific locus in two patients with normal karyotypes, while array CGH, performed for two patients, has delineated the extent of the deleted segments and the involved genes. LETM1, the main candidate gene for the seizure phenotype, was found deleted in the two patients tested by array CGH; nevertheless, one of them did not manifest seizures. The study emphasized the previous. Conclusion: WHS is a contiguous gene syndrome resulting from hemizygosity of the terminal 2 Mb of 4p16.3 region. The Branchial fistula, detected in one of our patients is a new finding that, to our knowledge, was not reported. [ABSTRACT FROM AUTHOR]

Published
2021
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23. Therapeutic effect of Valproic acid in conjunction with physical rehabilitation in the treatment of Spinal Muscular Atrophy Type II.

Author

ELNEGAMY, TAMER EMAM, MEGAHED, HISHAM, ALI, SAFY ELDIN M. ABO, BATTESHA, HANAN H., and SHAFEEK, MARIAN M.

Subjects
*SPINAL muscular atrophy, *VALPROIC acid, *MEDICAL rehabilitation, *TREATMENT effectiveness, *TREATMENT programs
Abstract

Objectives: To evaluate the effect of Valproic acid in conjunction with a physical rehabilitation program in the treatment of patients with Spinal Muscular Atrophy Type II (SMA II). Methods: Twenty-eight Egyptian children who fulfilled the inclusion criteria of SMA II participated in the study. They were treated with Valproic Acid (VPA) and suitable physical therapy program according to the patient's physical problems. All patients were examined five times during one year to evaluate the patients every three months using a modified Hammersmith functional motor scale (MHFMS). Results: All patients showed significant improvement in post-treatment mean values compared to the pretreatment mean value (P<0.05). Significant improvement was observed in favor of younger children when children were less than three years of age patients to children more than three years of age. Conclusion: Clinical trials are still ongoing to detect a proper drug that is less expensive, safe, and affordable, so using VPA in treating SMA patients is still considered. [ABSTRACT FROM AUTHOR]

Published
2021
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Author

Schaffer, Ashleigh E, Schaffer, Ashleigh E, Breuss, Martin W, Caglayan, Ahmet Okay, Al-Sanaa, Nouriya, Al-Abdulwahed, Hind Y, Kaymakçalan, Hande, Yılmaz, Cahide, Zaki, Maha S, Rosti, Rasim O, Copeland, Brett, Baek, Seung Tae, Musaev, Damir, Scott, Eric C, Ben-Omran, Tawfeg, Kariminejad, Ariana, Kayserili, Hulya, Mojahedi, Faezeh, Kara, Majdi, Cai, Na, Silhavy, Jennifer L, Elsharif, Seham, Fenercioglu, Elif, Barshop, Bruce A, Kara, Bulent, Wang, Rengang, Stanley, Valentina, James, Kiely N, Nachnani, Rahul, Kalur, Aneesha, Megahed, Hisham, Incecik, Faruk, Danda, Sumita, Alanay, Yasemin, Faqeih, Eissa, Melikishvili, Gia, Mansour, Lobna, Miller, Ian, Sukhudyan, Biayna, Chelly, Jamel, Dobyns, William B, Bilguvar, Kaya, Jamra, Rami Abou, Gunel, Murat, Gleeson, Joseph G, Schaffer, Ashleigh E, Schaffer, Ashleigh E, Breuss, Martin W, Caglayan, Ahmet Okay, Al-Sanaa, Nouriya, Al-Abdulwahed, Hind Y, Kaymakçalan, Hande, Yılmaz, Cahide, Zaki, Maha S, Rosti, Rasim O, Copeland, Brett, Baek, Seung Tae, Musaev, Damir, Scott, Eric C, Ben-Omran, Tawfeg, Kariminejad, Ariana, Kayserili, Hulya, Mojahedi, Faezeh, Kara, Majdi, Cai, Na, Silhavy, Jennifer L, Elsharif, Seham, Fenercioglu, Elif, Barshop, Bruce A, Kara, Bulent, Wang, Rengang, Stanley, Valentina, James, Kiely N, Nachnani, Rahul, Kalur, Aneesha, Megahed, Hisham, Incecik, Faruk, Danda, Sumita, Alanay, Yasemin, Faqeih, Eissa, Melikishvili, Gia, Mansour, Lobna, Miller, Ian, Sukhudyan, Biayna, Chelly, Jamel, Dobyns, William B, Bilguvar, Kaya, Jamra, Rami Abou, Gunel, Murat, and Gleeson, Joseph G

Published
2018

30. Utility of whole exome sequencing for the early diagnosis of pediatric-onset cerebellar atrophy associated with developmental delay in an inbred population

Author

Megahed, Hisham, primary, Nicouleau, Michaël, additional, Barcia, Giulia, additional, Medina-Cano, Daniel, additional, Siquier-Pernet, Karine, additional, Bole-Feysot, Christine, additional, Parisot, Mélanie, additional, Masson, Cécile, additional, Nitschké, Patrick, additional, Rio, Marlène, additional, Bahi-Buisson, Nadia, additional, Desguerre, Isabelle, additional, Munnich, Arnold, additional, Boddaert, Nathalie, additional, Colleaux, Laurence, additional, and Cantagrel, Vincent, additional

Published
2016
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33. MYC family amplification and clinical risk-factors interact to predict an extremely poor prognosis in childhood medulloblastoma

Author

Ryan, Sarra L., primary, Schwalbe, Ed C., additional, Cole, Michael, additional, Lu, Yuan, additional, Lusher, Meryl E., additional, Megahed, Hisham, additional, O’Toole, Kieran, additional, Nicholson, Sarah Leigh, additional, Bognar, Laszlo, additional, Garami, Miklos, additional, Hauser, Peter, additional, Korshunov, Andrey, additional, Pfister, Stefan M., additional, Williamson, Daniel, additional, Taylor, Roger E., additional, Ellison, David W., additional, Bailey, Simon, additional, and Clifford, Steven C., additional

Published
2011
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34. TP53 Mutations in Favorable-Risk Wnt/Wingless-Subtype Medulloblastomas

Author

Lindsey, Janet C., primary, Hill, Rebecca M., additional, Megahed, Hisham, additional, Lusher, Meryl E., additional, Schwalbe, Ed C., additional, Cole, Michael, additional, Hogg, Twala L., additional, Gilbertson, Richard J., additional, Ellison, David W., additional, Bailey, Simon, additional, and Clifford, Steven C., additional

Published
2011
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35. Definition of Disease-Risk Stratification Groups in Childhood Medulloblastoma Using Combined Clinical, Pathologic, and Molecular Variables

Author

Ellison, David W., primary, Kocak, Mehmet, additional, Dalton, James, additional, Megahed, Hisham, additional, Lusher, Meryl E., additional, Ryan, Sarra L., additional, Zhao, Wei, additional, Nicholson, Sarah Leigh, additional, Taylor, Roger E., additional, Bailey, Simon, additional, and Clifford, Steven C., additional

Published
2011
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37. Rapid Diagnosis of Medulloblastoma Molecular Subgroups

Author

Schwalbe, Ed C., primary, Lindsey, Janet C., additional, Straughton, Debbie, additional, Hogg, Twala L., additional, Cole, Michael, additional, Megahed, Hisham, additional, Ryan, Sarra L., additional, Lusher, Meryl E., additional, Taylor, Michael D., additional, Gilbertson, Richard J., additional, Ellison, David W., additional, Bailey, Simon, additional, and Clifford, Steven C., additional

Published
2011
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38. Correlation between clinical features and MECP2gene mutations in patients with Rett syndrome

Author

Megahed, Hisham, Hindawy, Amina, and Mohamady, Mohamed

Abstract

Rett syndrome is a progressive neurodevelopment disorder which mainly affects females and is a common cause of mental retardation. Loss of purposeful hand movements, regression of acquired cognitive and motor skills and autistic features are the main criteria associated with this disorder. Sixty to ninety percent of the cases show MECP2gene mutations, which reside on the X chromosome. MECP2regulates gene expression in a repressive manner.

Published
2015
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