This report describes ciliary dyskinesia, primary, 18 (CILD18), which is a subtype of primary ciliary dyskinesia. The human gene implicated in this disease is dynein axonemal assembly factor 5 (DNAAF5), also known as HEATR2 (HEAT repeat containing 2). CILD18 is inherited as an autosomal recessive. There is a single orthologous gene in Drosophila, Dmel\HEATR2, for which a classical amorphic allele, RNAi-targeting constructs, and an allele caused by insertional mutagenesis of a reporter gene have been generated.
The human DNAAF5 gene has not been introduced into flies.
An amorphic allele of Dmel\HEATR2 is lethal when homozygous. Animals with reduced function of HEATR2, effected by targeted RNAi, exhibit auditory perception defects, an uncoordinated phenotype, and immotile sperm; cilia of chordotonal organs are present, but their axonemes lack both outer and inner dynein arms.
Drosophila orthologs of several other genes required for assembly of dynein arms and implicated in ciliary dyskinesia in human have been found to affect auditory perception in flies (see FBhh0000436 and FBhh0001028).
[updated Dec. 2019 by FlyBase; FBrf0222196]
Primary ciliary dyskinesia is a disorder characterized by chronic respiratory tract infections, abnormally positioned internal organs, recurrent ear infections (especially in children) and infertility (especially in males). About 50 percent of people with primary ciliary dyskinesia have a mirror-image reversal of their internal organs (situs inversus). [from Genetics Home Reference, primary ciliary dyskinesia; 2016.11.21]
[CILIARY DYSKINESIA, PRIMARY, 18; CILD18](https://omim.org/entry/614874)
[DYNEIN, AXONEMAL, ASSEMBLY FACTOR 5; DNAAF5](https://omim.org/entry/614864)
See general description of primary ciliary dyskinesia, above.
Primary ciliary dyskinesia-18 (CILD18) is caused by homozygous mutation in the HEATR2 gene. [from MIM:614874; 2016.11.21]
HEATR is required for the proper formation of outer axonemal dynein arms in cilia and flagella (Horani et al., 2012; pubmed:23040496). [from MIM:614864; 2016.11.21]
One to one: 1 human to 1 Drosophila.
Ortholog of human DNAAF5 gene (1 Drosophila to 1 human). Dmel\HEATR2 shares 31% identity and 51% similarity with human DNAAF5; each contains multiple HEAT repeats.
