@article {806,
	title = {Biallelic loss of function variants in SYT2 cause a treatable congenital onset presynaptic myasthenic syndrome.},
	journal = {Am J Med Genet A},
	volume = {182},
	year = {2020},
	month = {2020 10},
	pages = {2272-2283},
	abstract = {<p>Synaptotagmins are integral synaptic vesicle membrane proteins that function as calcium sensors and regulate neurotransmitter release at the presynaptic nerve terminal. Synaptotagmin-2 (SYT2), is the major isoform expressed at the neuromuscular junction. Recently, dominant missense variants in SYT2 have been reported as a rare cause of distal motor neuropathy and myasthenic syndrome, manifesting with stable or slowly progressive distal weakness of variable severity along with presynaptic NMJ impairment. These variants are thought to have a dominant-negative effect on synaptic vesicle exocytosis, although the precise pathomechanism remains to be elucidated. Here we report seven patients of five families, with biallelic loss of function variants in SYT2, clinically manifesting with a remarkably consistent phenotype of severe congenital onset hypotonia and weakness, with variable degrees of respiratory involvement. Electrodiagnostic findings were consistent with a presynaptic congenital myasthenic syndrome (CMS) in some. Treatment with an acetylcholinesterase inhibitor pursued in three patients showed clinical improvement with increased strength and function. This series further establishes SYT2 as a CMS-disease gene and expands its clinical and genetic spectrum to include recessive loss-of-function variants, manifesting as a severe congenital onset presynaptic CMS with potential treatment implications.</p>},
	keywords = {Adolescent, Child, Child, Preschool, Female, Genetic Predisposition to Disease, Humans, Male, Muscle Hypotonia, Muscle Weakness, Mutation, Missense, Myasthenic Syndromes, Congenital, Pedigree, Phenotype, Synaptic Transmission, Synaptotagmin II},
	issn = {1552-4833},
	doi = {10.1002/ajmg.a.61765},
	author = {Donkervoort, Sandra and Mohassel, Payam and Laugwitz, Lucia and Zaki, MAH S and Kamsteeg, Erik-Jan and Maroofian, Reza and Chao, Katherine R and Verschuuren-Bemelmans, Corien C and Horber, Veronka and Fock, Annemarie J M and McCarty, Riley M and Jain, Minal S and Biancavilla, Victoria and McMacken, Grace and Nalls, Matthew and Voermans, Nicol C and Elbendary, Hasnaa M and Snyder, Molly and Cai, Chunyu and Lehky, Tanya J and Stanley, Valentina and Iannaccone, Susan T and Foley, A Reghan and Lochm{\"u}ller, Hanns and Gleeson, Joseph and Houlden, Henry and Haack, Tobias B and Horvath, Rita and B{\"o}nnemann, Carsten G}
}
@article {571,
	title = {Recessive mutations in muscle-specific isoforms of FXR1 cause congenital multi-minicore myopathy.},
	journal = {Nat Commun},
	volume = {10},
	year = {2019},
	month = {2019 02 15},
	pages = {797},
	abstract = {<p>FXR1 is an alternatively spliced gene that encodes RNA binding proteins (FXR1P) involved in muscle development. In contrast to other tissues, cardiac and skeletal muscle express two FXR1P isoforms that incorporate an additional exon-15. We report that recessive mutations in this particular exon of FXR1 cause congenital multi-minicore myopathy in humans and mice. Additionally, we show that while Myf5-dependent depletion of all FXR1P isoforms is neonatal lethal, mice carrying mutations in exon-15 display non-lethal myopathies which vary in severity depending on the specific effect of each mutation on the protein.</p>},
	keywords = {Animals, Cells, Cultured, Exons, Gene Expression, Genes, Recessive, Genetic Predisposition to Disease, HEK293 Cells, HeLa Cells, Humans, Mice, Transgenic, Muscle, Skeletal, Mutation, Myopathies, Structural, Congenital, Ophthalmoplegia, RNA-Binding Proteins, Ryanodine Receptor Calcium Release Channel},
	issn = {2041-1723},
	doi = {10.1038/s41467-019-08548-9},
	author = {Esta{\~n}, Mar{\'\i}a Cristina and Fern{\'a}ndez-N{\'u}{\~n}ez, Elisa and Zaki, Maha S and Esteban, Mar{\'\i}a Isabel and Donkervoort, Sandra and Hawkins, Cynthia and Caparros-Martin, Jos{\'e} A and Saade, Dimah and Hu, Ying and Bolduc, Veronique and Chao, Katherine Ru-Yui and Nevado, Juli{\'a}n and Lamuedra, Ana and Largo, Raquel and Herrero-Beaumont, Gabriel and Regadera, Javier and Hernandez-Chico, Concepci{\'o}n and Tizzano, Eduardo F and Martinez-Glez, Victor and Carvajal, Jaime J and Zong, Ruiting and Nelson, David L and Otaify, Ghada A and Temtamy, Samia and Aglan, Mona and Issa, Mahmoud and B{\"o}nnemann, Carsten G and Lapunzina, Pablo and Yoon, Grace and Ruiz-Perez, Victor L}
}
