@article {75,
	title = {Bi-allelic GOT2 Mutations Cause a Treatable Malate-Aspartate Shuttle-Related Encephalopathy.},
	journal = {Am J Hum Genet},
	volume = {105},
	year = {2019},
	month = {2019 Sep 05},
	pages = {534-548},
	abstract = {<p>Early-infantile encephalopathies with epilepsy are devastating conditions mandating an accurate diagnosis to guide proper management. Whole-exome sequencing was used to investigate the disease etiology in four children from independent families with intellectual disability and epilepsy, revealing bi-allelic GOT2 mutations. In-depth metabolic studies in individual 1 showed low plasma serine, hypercitrullinemia, hyperlactatemia, and hyperammonemia. The epilepsy was serine and pyridoxine responsive. Functional consequences of observed mutations were tested by measuring enzyme activity and by cell and animal models. Zebrafish and mouse models were used to validate brain developmental and functional defects and to test therapeutic strategies. GOT2 encodes the mitochondrial glutamate oxaloacetate transaminase. GOT2 enzyme activity was deficient in fibroblasts with bi-allelic mutations. GOT2, a member of the malate-aspartate shuttle, plays an essential role in the intracellular NAD(H) redox balance. De novo serine biosynthesis was impaired in fibroblasts with GOT2 mutations and GOT2-knockout HEK293 cells. Correcting the highly oxidized cytosolic NAD-redox state by pyruvate~supplementation restored serine biosynthesis in GOT2-deficient cells. Knockdown of got2a in zebrafish resulted in a brain developmental defect associated with seizure-like electroencephalography spikes, which could be rescued by supplying pyridoxine in embryo water. Both pyridoxine and serine synergistically rescued embryonic developmental defects in zebrafish got2a morphants. The two treated individuals reacted favorably to their treatment. Our data provide a mechanistic basis for the biochemical abnormalities in GOT2 deficiency that may also hold for other MAS defects.</p>},
	issn = {1537-6605},
	doi = {10.1016/j.ajhg.2019.07.015},
	author = {van Karnebeek, Clara D M and Ramos, R{\'u}ben J and Wen, Xiao-Yan and Tarailo-Graovac, Maja and Gleeson, Joseph G and Skrypnyk, Cristina and Brand-Arzamendi, Koroboshka and Karbassi, Farhad and Issa, Mahmoud Y and van der Lee, Robin and Dr{\"o}gem{\"o}ller, Britt I and Koster, Janet and Rousseau, Justine and Campeau, Philippe M and Wang, Youdong and Cao, Feng and Li, Meng and Ruiter, Jos and Ciapaite, Jolita and Kluijtmans, Leo A J and Willemsen, Michel A A P and Jans, Judith J and Ross, Colin J and Wintjes, Liesbeth T and Rodenburg, Richard J and Huigen, Marleen C D G and Jia, Zhengping and Waterham, Hans R and Wasserman, Wyeth W and Wanders, Ronald J A and Verhoeven-Duif, Nanda M and Zaki, Maha S and Wevers, Ron A}
}
@article {70,
	title = {Redefining the Etiologic Landscape of Cerebellar Malformations.},
	journal = {Am J Hum Genet},
	volume = {105},
	year = {2019},
	month = {2019 Sep 05},
	pages = {606-615},
	abstract = {<p>Cerebellar malformations are diverse congenital anomalies frequently associated with developmental disability. Although genetic and prenatal non-genetic causes have been described, no systematic analysis has been performed. Here, we present a large-exome sequencing study of Dandy-Walker malformation (DWM) and cerebellar hypoplasia (CBLH). We performed exome sequencing in 282 individuals from 100 families with DWM or CBLH, and we established a molecular diagnosis in 36 of 100 families, with a significantly higher yield for CBLH (51\%) than for DWM (16\%). The 41 variants impact 27 neurodevelopmental-disorder-associated genes, thus demonstrating that CBLH and DWM are often features of monogenic neurodevelopmental disorders. Though only seven monogenic causes (19\%) were identified in more than one individual, neuroimaging review of 131 additional individuals confirmed cerebellar abnormalities in 23 of 27 genetic disorders (85\%). Prenatal risk factors were frequently found among individuals without a genetic diagnosis (30 of 64 individuals [47\%]). Single-cell RNA sequencing of prenatal human cerebellar tissue revealed gene enrichment in neuronal and vascular cell types; this suggests that defective vasculogenesis may disrupt cerebellar development. Further, de novo gain-of-function variants in PDGFRB, a tyrosine kinase receptor essential for vascular progenitor signaling, were associated with CBLH, and this discovery links genetic and non-genetic etiologies. Our results suggest that genetic defects impact specific cerebellar cell types and implicate abnormal vascular development as a mechanism for cerebellar malformations. We also confirmed a major contribution for non-genetic prenatal factors in individuals with cerebellar abnormalities, substantially influencing diagnostic evaluation and counseling regarding recurrence risk and prognosis.</p>},
	issn = {1537-6605},
	doi = {10.1016/j.ajhg.2019.07.019},
	author = {Aldinger, Kimberly A and Timms, Andrew E and Thomson, Zachary and Mirzaa, Ghayda M and Bennett, James T and Rosenberg, Alexander B and Roco, Charles M and Hirano, Matthew and Abidi, Fatima and Haldipur, Parthiv and Cheng, Chi V and Collins, Sarah and Park, Kaylee and Zeiger, Jordan and Overmann, Lynne M and Alkuraya, Fowzan S and Biesecker, Leslie G and Braddock, Stephen R and Cathey, Sara and Cho, Megan T and Chung, Brian H Y and Everman, David B and Zarate, Yuri A and Jones, Julie R and Schwartz, Charles E and Goldstein, Amy and Hopkin, Robert J and Krantz, Ian D and Ladda, Roger L and Leppig, Kathleen A and McGillivray, Barbara C and Sell, Susan and Wusik, Katherine and Gleeson, Joseph G and Nickerson, Deborah A and Bamshad, Michael J and Gerrelli, Dianne and Lisgo, Steven N and Seelig, Georg and Ishak, Gisele E and Barkovich, A James and Curry, Cynthia J and Glass, Ian A and Millen, Kathleen J and Doherty, Dan and Dobyns, William B}
}
