Biallelic variants in OGDH encoding oxoglutarate dehydrogenase lead to a neurodevelopmental disorder characterized by global developmental delay, movement disorder, and metabolic abnormalities.

Genetics in medicine : official journal of the American College of Medical Genetics 2023 Feb

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This study aimed to establish the genetic cause of a novel autosomal recessive neurodevelopmental disorder characterized by global developmental delay, movement disorder, and metabolic abnormalities. We performed a detailed clinical characterization of 4 unrelated individuals from consanguineous families with a neurodevelopmental disorder. We used exome sequencing or targeted-exome sequencing, cosegregation, in silico protein modeling, and functional analyses of variants in HEK293 cells and Drosophila melanogaster, as well as in proband-derived fibroblast cells. In the 4 individuals, we identified 3 novel homozygous variants in oxoglutarate dehydrogenase (OGDH) (NM_002541.3), which encodes a subunit of the tricarboxylic acid cycle enzyme α-ketoglutarate dehydrogenase. In silico homology modeling predicts that c.566C>T:p.(Pro189Leu) and c.890C>A:p.(Ser297Tyr) variants interfere with the structure and function of OGDH. Fibroblasts from individual 1 showed that the p.(Ser297Tyr) variant led to a higher degradation rate of the OGDH protein. OGDH protein with p.(Pro189Leu) or p.(Ser297Tyr) variants in HEK293 cells showed significantly lower levels than the wild-type protein. Furthermore, we showed that expression of Drosophila Ogdh (dOgdh) carrying variants homologous to p.(Pro189Leu) or p.(Ser297Tyr), failed to rescue developmental lethality caused by loss of dOgdh. SpliceAI, a variant splice predictor, predicted that the c.935G>A:p.(Arg312Lys)/p.(Phe264_Arg312del) variant impacts splicing, which was confirmed through a mini-gene assay in HEK293 cells. We established that biallelic variants in OGDH cause a neurodevelopmental disorder with metabolic and movement abnormalities. Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.

Citation

Ella F Whittle, Madison Chilian, Ehsan Ghayoor Karimiani, Helga Progri, Daniela Buhas, Melis Kose, Rebecca D Ganetzky, Mehran Beiraghi Toosi, Paria Najarzadeh Torbati, Reza Shervin Badv, Ivan Shelihan, Hui Yang, Houda Zghal Elloumi, Sukyeong Lee, Yalda Jamshidi, Alan M Pittman, Henry Houlden, Erika Ignatius, Shamima Rahman, Reza Maroofian, Wan Hee Yoon, Christopher J Carroll. Biallelic variants in OGDH encoding oxoglutarate dehydrogenase lead to a neurodevelopmental disorder characterized by global developmental delay, movement disorder, and metabolic abnormalities. Genetics in medicine : official journal of the American College of Medical Genetics. 2023 Feb;25(2):100332