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FB2026_01
,
released March 12, 2026
This report describes mitochondrial complex IV disorder (postulated), CEP89-related. A homozygous deletion of CEP89 (Centrosomal protein 89) was identified in a patient with isolated complex IV deficiency, intellectual disability and multisystemic problems (FBrf0222034). Very little is known about the function of this protein. There is a single orthologous gene in flies, Dmel\Cep89, for which RNAi-targeting constructs are available.
The human CEP89 gene has not been introduced into flies.
Ubiquitous RNAi-knockdown of Dmel\Cep89 decreases complex IV activity and results in lethality during the pupal stage. Eye-specfic RNAi-knockdown results in defects in mitochondrial integrity, membrane depolarization, and synaptic transmission in photoreceptor neurons.
[updated Aug. 2016 by FlyBase; FBrf0222196]
Van Bon et al. (2013, pubmed:23575228) reported a 12-year-old girl, born of consanguineous Turkish parents, with severe intellectual disability, lack of speech development, facial dysmorphism, increased serum lactate and cystinuria. [from MIM:220110; 2019.05.31]
After excluding most genes known to be implicated in mitochondrial complex IV deficiency, homozygous deletion of the CEP89 gene was identified in a patient with isolated complex IV deficiency, intellectual disability and multisystemic problems.
It was determined that the affected individual carryied an isolated mitochondrial complex IV deficiency associated with a homozygous 78-kb deletion on chromosome 19q13.11 including exons 15-19 of the CEP89 gene as well as the SLC7A9 gene. The unaffected parents were heterozygous for the deletion. Cystinuria is known to be caused by biallelic loss of SLC7A9, however, the additional features had never been reported in cystinuria, implicating loss of CEP89 in complex IV deficiency. [from MIM:220110; 2019.05.31]
Very little is known about function of the protein encoded by centrosomal protein 89 (CEP89). It has been shown to be associated with centrioles and, in that capacity, to function in cilia initiation. It also appears to play a role in mitochondrial metabolism, as shown in both human and Drosophila (FBrf0222034).
One to one (1 human to 1 Drosophila).
Moderate-scoring ortholog of human CEP89; reciprocal best hit (1 Drosophila to 1 human). Dmel\Cep89 shares 24% identity and 40% similarity with the human gene.