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FB2026_01
,
released March 12, 2026
The human gene DNMBP has been implicated in the development of infantile-onset cataracts based on exome-sequencing analysis of three consanguineous families affected by the disease. Designated cataract 48 (CTRCT48), this form of infantile cataracts exhibits autosomal recessive inheritance. DNMBP ('dynamin binding protein') encodes a protein belonging to the guanine nucleotide exchange factor family; it is thought to play a role in the configuration of cell junctions. There is a single low-scoring ortholog of DNMBP in Drosophila, Dmel\sif, for which a loss-of-function mutation, RNAi targeting constructs, and many alleles caused by insertional mutagenesis have been generated. There are multiple genes in this family in both species; Dmel\sif is more closely related to other human genes and is most closely related to TIAM1 and TIAM2.
The human DNMBP has not been introduced into flies.
Animals hemizygous for a loss-of-function allele of Dmel\sif exhibit neuroanatomy defects of larval neuromuscular junctions and reduced locomotor activity. Targeted knockout in the developing eye, effected by RNAi, impacts septate junctions (which functionally correspond to tight junctions in vertebrates) between photoreceptors and cone cells; some of the pigment cells that secrete the lenses are misshapen or lost. A small number of genetic and physical interactions have been described for Dmel\sif; see below and in the sif gene report.
[updated May 2019 by FlyBase; FBrf0222196]
[CATARACT 48; CTRCT48](https://omim.org/entry/618415)
[DYNAMIN-BINDING PROTEIN; DNMBP](https://omim.org/entry/611282)
Infantile cataracts are characterized by opacity that develops in the crystalline lens of the eye within the first year of life. A recent systematic analysis has estimated the frequency of infantile cataracts as 4.2 cases per 10,000 children. Visual impairment due to cataracts in children causes a substantial lifelong burden on quality of life and also contributes to a considerable socioeconomic burden (FBrf0240231 and references cited therein).
Cataract-48 (CTRCT48) is characterized by infantile or early-childhood cataracts and visual impairment (Ansar et al., 2018; pubmed:30290152, FBhh0000949).
DNMBP is implicated infantile cataracts on the basis of exome-sequencing analysis of three consanguineous families affected by bilateral infantile cataracts; autosomal recessive inheritance is observed (FBrf0240231).
Cataract-48 (CTRCT48) is caused by homozygous mutation in the DNMBP gene.
DNMBP (Dynamin Binding Protein) encodes a protein belonging to the guanine nucleotide exchange factor family, and which regulates the configuration of cell junctions. It contains multiple binding sites for dynamin and thus links dynamin to actin regulatory proteins. [Gene Cards, DNMBP; 2019.01.07]
Dynamins are microtubule-associated force-producing proteins involved in producing microtubule bundles and able to bind and hydrolyze GTP. [Gene Cards, DNM1, DNM2; 2019.01.07]
Many to many (multiple related genes in both species). Dmel\sif is the only fly gene called as an ortholog of DNMBP, however it is more closely related to other human genes; it is most closely related to TIAM1 and TIAM2.
Low-scoring ortholog of human DNMBP (multiple related genes in both species). Dmel\sif is most closely related to TIAM1 and TIAM2; it shares 19% identity and 33% similarity with the human DNMBP gene.