Mitochondrial disease
Gene: OGDH
Detailed clinical characterization of 4 unrelated individuals from consanguineous families with a neurodevelopment disorder, using WES, cosegregation, in silicon protein modelling, and functional analysis of variants in HEK293 cells and drosophila, as well as in pro band-derived fibroblast cells.
Identified 3 novel homozygous variants in OGDH (oxoglutarate dehydrogenase). OGDH is an E1 component of the alpha-ketoglutarate dehydrogenase complex, a multi subunit enzyme consisting of OGDH, DLST and DLD. Alpha-KGDH catalyses the conversion of alpha-ketoglutarate to succinylcholine-coenzyme A in the TCA cycle.
Fibroblasts from one individual demonstrated that p.(Ser297Tyr) variant led to higher degradation rate of OGDH protein.
OGDH protein with p.(Pro189Leu) or p.(Ser297Tyr) in HEK293 cells showed significantly lower levels than wild-type.
SpliceAI predicted that c.935G<A; p.(Arg312Lys/p.(Phe264_Arg312del) impacts splicing, which was confirmed by a mini-gene assay in HEK293 cells.
Conclusion: Biallelic variants in OGDH cause a neurodevelopment disorder with metabolic and movement abnormalities. Onset of presentation ranged from 6 weeks of age to 3 years old. All described individuals shared the clinical features of GDD, hypotonia, metabolic acidosis and increased serum lactate. Additional shared clinical features included dystonia (3/4), microcephaly (3/4), abnormal nasal bridge morphology (3/4), hyperammonemia (3/4), hyperglutaminemia (3/3 who were tested), and elevated alpha-ketoglutarate in the urine (2/2 who were tested).Created: 2 Feb 2023, 3:22 a.m. | Last Modified: 2 Feb 2023, 3:22 a.m.
Panel Version: 0.852
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Oxoglutarate dehydrogenase deficiency, MIM# 203740
Publications
Two siblings reported with homozygous missense variant in this gene and global developmental delay, elevated lactate, ataxia and seizure. Fibroblast analysis and modeling of the mutation in Drosophila were used to evaluate pathogenicity of the variant. Note previous report of an individual with developmental delay, hypotonia, and movement disorders and metabolic decompensation and biochemical evidence of OGDH deficiency but genetic testing not done.
Sources: LiteratureCreated: 3 Dec 2021, 3:22 a.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Oxoglutarate dehydrogenase deficiency, MIM# 203740; Developmental delay; ataxia; seizure; raised lactate
Publications
Gene: ogdh has been classified as Green List (High Evidence).
Gene: ogdh has been classified as Green List (High Evidence).
Phenotypes for gene: OGDH were changed from Developmental delay; ataxia; seizure; raised lactate to Oxoglutarate dehydrogenase deficiency, MIM# 203740; Developmental delay; ataxia; seizure; raised lactate
Gene: ogdh has been classified as Amber List (Moderate Evidence).
Gene: ogdh has been classified as Amber List (Moderate Evidence).
gene: OGDH was added gene: OGDH was added to Mitochondrial disease. Sources: Literature Mode of inheritance for gene: OGDH was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: OGDH were set to 32383294 Phenotypes for gene: OGDH were set to Developmental delay; ataxia; seizure; raised lactate Review for gene: OGDH was set to AMBER