1. NEXMIF encephalopathy: an X-linked disorder with male and female phenotypic patterns
- Author
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Stamberger, H., Hammer, T.B., Gardella, E., Vlaskamp, D.R.M., Bertelsen, B., Mandelstam, S., Lange, I. de, Zhang, J., Myers, C.T., Fenger, C., Afawi, Z., Fuerte, E.P. Almanza, Andrade, D.M., Balcik, Y., Zeev, B. Ben, Bennett, M.F., Berkovic, S.F., Isidor, B., Bouman, A., Brilstra, E., Ø, L. Busk, Cairns, A., Caumes, R., Chatron, N., Dale, R.C., Geus, C. de, Edery, P., Gill, D., Granild-Jensen, J.B., Gunderson, L., Gunning, B., Heimer, G., Helle, J.R., Hildebrand, M.S., Hollingsworth, G., Kharytonov, V., Klee, E.W., Koeleman, B.P.C., Koolen, D.A., Korff, C., Küry, S., Lesca, G., Lev, D., Leventer, R.J., Mackay, M.T., Macke, E.L., McEntagart, M., Mohammad, S.S., Monin, P., Montomoli, M., Morava, E., Moutton, S., Muir, A.M., Parrini, E., Procopis, P., Ranza, E., Reed, L., Reif, P.S., Rosenow, F., Rossi, M., Sadleir, L.G., Sadoway, T., Schelhaas, H.J., Schneider, A.L., Shah, K., Shalev, R., Sisodiya, S.M., Smol, T., Stumpel, C., Stuurman, K., Symonds, J.D., Mau-Them, F.T., Verbeek, N., Verhoeven, J.S., Wallace, G., Yosovich, K., Zarate, Y.A., Zerem, A., Zuberi, S.M., Guerrini, R., Mefford, H.C., Patel, C., Zhang, Y.H., Møller, R.S., Scheffer, I.E., Stamberger, H., Hammer, T.B., Gardella, E., Vlaskamp, D.R.M., Bertelsen, B., Mandelstam, S., Lange, I. de, Zhang, J., Myers, C.T., Fenger, C., Afawi, Z., Fuerte, E.P. Almanza, Andrade, D.M., Balcik, Y., Zeev, B. Ben, Bennett, M.F., Berkovic, S.F., Isidor, B., Bouman, A., Brilstra, E., Ø, L. Busk, Cairns, A., Caumes, R., Chatron, N., Dale, R.C., Geus, C. de, Edery, P., Gill, D., Granild-Jensen, J.B., Gunderson, L., Gunning, B., Heimer, G., Helle, J.R., Hildebrand, M.S., Hollingsworth, G., Kharytonov, V., Klee, E.W., Koeleman, B.P.C., Koolen, D.A., Korff, C., Küry, S., Lesca, G., Lev, D., Leventer, R.J., Mackay, M.T., Macke, E.L., McEntagart, M., Mohammad, S.S., Monin, P., Montomoli, M., Morava, E., Moutton, S., Muir, A.M., Parrini, E., Procopis, P., Ranza, E., Reed, L., Reif, P.S., Rosenow, F., Rossi, M., Sadleir, L.G., Sadoway, T., Schelhaas, H.J., Schneider, A.L., Shah, K., Shalev, R., Sisodiya, S.M., Smol, T., Stumpel, C., Stuurman, K., Symonds, J.D., Mau-Them, F.T., Verbeek, N., Verhoeven, J.S., Wallace, G., Yosovich, K., Zarate, Y.A., Zerem, A., Zuberi, S.M., Guerrini, R., Mefford, H.C., Patel, C., Zhang, Y.H., Møller, R.S., and Scheffer, I.E.
- Abstract
Contains fulltext : 231688.pdf (Publisher’s version ) (Closed access), PURPOSE: Pathogenic variants in the X-linked gene NEXMIF (previously KIAA2022) are associated with intellectual disability (ID), autism spectrum disorder, and epilepsy. We aimed to delineate the female and male phenotypic spectrum of NEXMIF encephalopathy. METHODS: Through an international collaboration, we analyzed the phenotypes and genotypes of 87 patients with NEXMIF encephalopathy. RESULTS: Sixty-three females and 24 males (46 new patients) with NEXMIF encephalopathy were studied, with 30 novel variants. Phenotypic features included developmental delay/ID in 86/87 (99%), seizures in 71/86 (83%) and multiple comorbidities. Generalized seizures predominated including myoclonic seizures and absence seizures (both 46/70, 66%), absence with eyelid myoclonia (17/70, 24%), and atonic seizures (30/70, 43%). Males had more severe developmental impairment; females had epilepsy more frequently, and varied from unaffected to severely affected. All NEXMIF pathogenic variants led to a premature stop codon or were deleterious structural variants. Most arose de novo, although X-linked segregation occurred for both sexes. Somatic mosaicism occurred in two males and a family with suspected parental mosaicism. CONCLUSION: NEXMIF encephalopathy is an X-linked, generalized developmental and epileptic encephalopathy characterized by myoclonic-atonic epilepsy overlapping with eyelid myoclonia with absence. Some patients have developmental encephalopathy without epilepsy. Males have more severe developmental impairment. NEXMIF encephalopathy arises due to loss-of-function variants.
- Published
- 2021