Status: I've confirmed PCD40 (CILD40) is caused by biallelic DNAH9 variants and have the key PMIDs. I'm now pulling the Loges and Fassad abstracts so I can quote them exactly.

Primary Ciliary Dyskinesia 40 (CILD40, DNAH9-related)

Method and limits. This report rests on web searches and PubMed E-utilities lookups. I could not read OMIM, Orphanet or ClinGen directly (the MalaCards fetch returned 403). Where a statement comes from a secondary aggregator, I say so. Not every detail below was checked against a primary abstract. Items marked [unverified] are from my background knowledge or an aggregator and should be checked before curation. Direct quotes below are short and come from search or abstract summaries, not full-text reading. Run just fetch-reference PMID:<id> and re-extract exact snippets before using any quote as evidence. The PMIDs listed here came from the PubMed search, but I did not confirm every one against the full record.

1. Disease information

• Overview. PCD40, or CILD40, is an autosomal recessive form of primary ciliary dyskinesia. It is caused by homozygous or compound heterozygous variants in DNAH9 on chromosome 17p12. DNAH9 encodes an outer dynein arm (ODA) heavy chain. The distinguishing feature is a mild respiratory phenotype with prominent laterality defects. (MalaCards; MedGen via NCBI mirror)
• Identifiers. MONDO:0032664; OMIM #618300; MedGen C4749028 (per the MedGen mirror URL; "1648365" in one search summary is probably a mis-transcription, so check it); gene DNAH9 (HGNC symbol; the KB form is lowercase hgnc:<n>, and I did not look up the number). (DrugMap; NORD/MONDO)
• Synonyms. CILD40; "Ciliary dyskinesia, primary, 40, with or without situs inversus"; PCD40.
• Data source. This is an aggregated, disease-level description built from case series. It is not EHR-derived.
• Parent and relatives. This is one of the genetically defined PCD subtypes, each of which has its own MONDO ID (MONDO:0014910 is another PCD subtype that appeared in the GenCC results, not this one).

2. Etiology

• Cause. Biallelic loss-of-function (LoF) variants in DNAH9. Loges et al. reported "loss-of-function mutations in DNAH9 in five independent families" (PMID:30471718). Fassad et al. identified DNAH9 mutations in PCD-clinic individuals with situs inversus and, in one case, male infertility (PMID:30471717).
• Risk and protective factors. None are established for this recessive monogenic condition. A common-variant study reported an interaction between DNAH9 and early-life smoke exposure for bronchial hyperresponsiveness (PMID:26797031), but that concerns asthma-type traits in the general population, not CILD40.
• Gene–environment. Tobacco smoke and airway infections plausibly worsen respiratory disease in any PCD. I found no CILD40-specific data [unverified].

3. Phenotypes

• Respiratory course. MalaCards says "compared with other CILDs the respiratory phenotype is relatively mild and patients typically do not develop serious lung disease." Symptoms typically begin in childhood as mild upper respiratory infections.
• Normal screening tests. One conference abstract reports normal nasal nitric oxide, normal ciliary beat frequency and preserved mucociliary clearance in three patients (ERJ abstract). This conflicts with Fassad, who found a reduced beat frequency in the distal cilia (see below). Likely explanation: the defect is subtle and regional, so results vary by method.
• Quality of life. No CILD40-specific data found.

4. Genetic / molecular information

• Gene. DNAH9, 17p12, dynein axonemal heavy chain 9, with ~70 exons [unverified]. The original gene description is Bartoloni et al. (PMID:11247663).
• Variants. Biallelic LoF (nonsense, frameshift, splice) and some missense variants have been reported across the case series above. I did not extract specific variant nomenclature or ClinVar classifications.
• Variant origin. Germline.
• Allele frequency / founder effects. Not checked. Check gnomAD and ClinVar before curation.
• Modifiers and epigenetics. None known.
• Chromosomal abnormalities. Not applicable.
• Gene-disease validity. The DrugMap/GenCC data list the DNAH9 association as strong; I could not read the ClinGen record. If a ClinGen assertion exists, cache it as CGGV: rather than recording a tier from memory.

5. Environmental information

No specific environmental or infectious causes. Secondary respiratory pathogens (e.g., Haemophilus influenzae, Pseudomonas aeruginosa) are expected as in other PCD forms [unverified for CILD40].

6. Mechanism / pathophysiology

Causal chain

1. Biallelic germline DNAH9 LoF variants lead to absent or truncated DNAH9 protein. (Demonstrated: Loges 2018, Fassad 2018.)
2. Loss of DNAH9 results in loss of DNAH9/DNAH5-containing type 2 ODAs, which is restricted to the distal region of the cilium. Fassad et al.: "DNAH9 and its partner heavy chain DNAH5 localize to type 2 ODAs of the distal cilium... a loss of DNAH9/DNAH5-containing type 2 ODAs that was restricted to the distal cilia region." Electron tomography confirmed regional loss of whole or partial ODAs. Loges et al. found that DNAH9-deficient cilia also lack other ODA components in the distal axoneme, and that DNAH9 interacts with DNAH5, DNAI2 and CCDC114. (Demonstrated, in human cells.)
3. Loss of distal type 2 ODAs leads to a reduced beat frequency with a subtle beat-pattern defect in the distal cilium portion. (Demonstrated, Fassad.) Proximal ODAs, which contain DNAH11 and DNAH5, are preserved, which explains the milder, sometimes near-normal, standard tests.
4. In motile monocilia of the embryonic node, impaired motility leads to defective leftward flow and randomized left-right axis determination. This is inferred from the genotype–phenotype pattern and from the general model of ODA-related laterality defects; I did not verify a DNAH9-specific node study.
5. Randomized laterality results in situs inversus and, in some cases, heterotaxy with congenital heart disease. (Observed in patients.)
6. In the airway, partially preserved ciliary function results in milder mucociliary clearance impairment, with childhood-onset cough and upper-airway infections. (Observed.)
7. In the male reproductive tract, impaired sperm flagellar motility results in asthenozoospermia and infertility. (Observed in a subset.)

Suggested ontology terms (check each with a lookup before binding): GO "outer dynein arm assembly" (GO:0036158, verify), "cilium movement" (GO:0003341, verify), "determination of left/right symmetry" (GO:0007368, verify); CL ciliated columnar epithelial cell of the airway, sperm (CL:0000019), embryonic node monocilia cells; GO:CC "outer dynein arm" (GO:0005858, verify).

Immune, metabolic and omics findings. None established for CILD40 in the humans reported. A mouse study (below) describes mucin accumulation and immune cell infiltration.

7. Anatomical structures affected

• Primary: motile cilia of the respiratory tract (nose, paranasal sinuses, bronchi), the embryonic left-right organizer (node), and sperm flagella.
• Secondary: heart (laterality-related CHD), middle ear (in other PCD forms; not verified here), gut (single jejunal atresia report).
• Subcellular: distal ciliary axoneme, outer dynein arms.
• Lateralization: the laterality phenotype is a mirror image, not an asymmetric loss.

8. Temporal development

• Onset: congenital, because laterality defects are present at birth. Respiratory symptoms appear in childhood.
• Progression: generally mild and slowly progressive or stable. Long-term data are lacking [unverified].
• Critical period: embryonic left-right patterning. This cannot be reversed postnatally.

9. Inheritance and population

• Inheritance: autosomal recessive (HP:0000007).
• Prevalence: CILD40 prevalence is not established. Overall PCD prevalence is roughly 1 in 10,000–20,000 [unverified for this report; check Orphanet]. DNAH9 variants appear to be a rare cause among PCD cases.
• Case series origins: European, Somali-British, Japanese, Chinese, and Bahraini patients have been reported, which suggests no single population is dominant. See Fassad, Loges, PMID:35050399, PMID:34008076 (Japanese fetus), PMID:39115416.
• Carrier frequency, penetrance, consanguinity: not examined.

10. Diagnostics

• Hallmark findings. Situs abnormality in a child with chronic respiratory symptoms should prompt PCD evaluation.
• Why standard tests can mislead. Because the defect is restricted to distal cilia, nasal NO, high-speed video analysis and routine transmission electron microscopy can look normal or near-normal. Loges et al. and Fassad et al. both describe this. The conference abstract reports normal nasal NO and ciliary beat frequency. So a normal screen does not rule out CILD40.
• More informative tests. Immunofluorescence for DNAH9 and DNAH5 along the cilium (showing a distal-only pattern), electron tomography, and genetic testing.
• Genetic testing. PCD multigene panel or exome sequencing including DNAH9; several of the cited cases were found by exome sequencing (PMID:34008076, PMID:33452233).
• Differential: other ODA defects (DNAH5, DNAI1, DNAH11), other laterality disorders (heterotaxy from ZIC3, MMP21, PKD1L1, GDF1; see PMID:42630107), and CF.
• Guideline. The practical guide for PCD diagnosis and management is a general PCD reference.

11. Prognosis

The lung disease is expected to be milder than other PCD forms. I found no CILD40-specific survival data. Prognosis in patients with complex CHD depends mainly on the cardiac lesion.

12. Treatment

No CILD40-specific trials were found. Management follows general PCD care: airway clearance physiotherapy (NCIT: verify), prompt antibiotic treatment of infections (NCIT:C15986 Pharmacotherapy; agents vary), vaccination (NCIT:C15346), management of sinus and ear disease, and surgical or medical care of CHD where present. Assisted reproduction is an option for infertile men. Mucolytics, long-term macrolides and inhaled antibiotics are used in other PCD forms [unverified for this subtype]. Experimental: a mouse/organoid study screened mitochondria-targeting drugs that partly improved cilia beating (see below); this is preclinical only. Gene therapy is not available.

13. Prevention

Genetic counseling for a recessive condition (25% recurrence risk per pregnancy, NCIT:C15240); carrier testing for relatives; prenatal or preimplantation testing where the familial variants are known. Early diagnosis is useful so that respiratory care can start even when screening tests look normal.

14. Other species / natural disease

Not checked (OMIA was not searched). Dynein arm defects cause PCD-like disease in dogs and other species, but I have no DNAH9-specific entries [unverified].

15. Model organisms

• Mouse, Dnah9 knockdown, plus airway organoids. Zheng et al. studied a patient with compound DNAH9 mutation. Per the summary I retrieved, the knockdown mice "recapitulated the patient phenotypes", with low lung function, mucin accumulation and immune cell infiltration; airway organoids were used to screen drugs, with mitochondria-targeting compounds partly improving cilia beating (PMID:35729109). Evidence source: model organism / in vitro. Limitation: this is a knockdown, not a null, and the cited patient's phenotype is what is "recapitulated", so fidelity to the laterality phenotype is not established here.
• Earlier work. Mislocalization of DNAH5 and DNAH9 in PCD respiratory cells (PMID:15750039), human cell evidence.
• Zebrafish, Chlamydomonas and other models: not searched.

Gaps to close before curation

1. Pull OMIM #618300 text, ClinVar/ClinGen entries and the Orphanet record through the repo's structured-source routes.
2. Read the Loges and Fassad full texts for variant nomenclature, cohort sizes and quotable snippets.
3. Check whether an HP term is appropriate for "distal ODA loss" or whether to leave it unbound.
4. Verify each HPO, GO and CL ID marked "verify" with a lookup. I did not run any term lookup, so no CURIE here is checked.
5. Resolve the conflict between normal ciliary beat frequency (conference abstract) and reduced frequency (Fassad).

Sources

• MalaCards, CILD40
• NORD/MONDO, ciliary dyskinesia, primary, 40
• DrugMap disease DISJWDP0
• MedGen C4749028 mirror
• Fassad et al. 2018, AJHG, PMID:30471717
• Loges et al. 2018, AJHG, PMID:30471718
• ERJ 2018 conference abstract on DNAH9 cilia
• PubMed E-utilities lookups for the other PMIDs cited above

Reference Validation

Checked with linkml-reference-validator 0.3.0.

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• HP:0031318 (1 mention) - the report calls it "Heterotaxy / laterality defect"; HP calls it Myofiber disarray
• HP:0004429 (1 mention) - the report calls it "verify"; HP calls it Recurrent viral infections
• HP:0002205 (1 mention) - the report calls it "verify"; HP calls it Recurrent respiratory infections
• HP:0012206 (1 mention) - the report calls it "verify"; HP calls it Abnormal sperm motility
• HP:0005214 (1 mention) - the report calls it "verify"; HP calls it Intestinal obstruction

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

• HP:0001627 (1 mention) - the report calls it "Congenital heart defect"; HP calls it Abnormal heart morphology, and lists "Congenital heart defect" among its other names