📋 Key Information Summary
- Fanconi anaemia (FA) is a rare autosomal recessive (rarely X-linked) inherited bone marrow failure syndrome caused by defects in the DNA interstrand crosslink (ICL) repair pathway — at least 22 complementation groups (FANCA–FANCW) are now identified.
- Incidence is approximately 1 in 160,000 live births; carrier frequency estimated at 1 in 180–300 in outbred populations, with higher rates in founder populations (Ashkenazi Jewish, Afrikaner, Spanish Romani).
- Over 60% of patients present with congenital anomalies including short stature, radial ray defects, hyperpigmentation, microcephaly, renal malformations, and small gonads; up to 30% are phenotypically normal at birth.
- Progressive bone marrow failure affects ≥80% of patients by age 40, progressing through hypocellular myelodysplasia to aplastic anaemia.
- Chromosomal breakage test (diepoxybutane or mitomycin C-induced) is the gold-standard diagnostic assay — demonstrates increased radial figures and chromosomal breaks in phytohaemagglutinin-stimulated T-lymphocytes.
- Patients harbour a markedly elevated lifetime risk of acute myeloid leukaemia (AML) and solid tumours (head and neck squamous cell carcinoma, vulvar, oesophageal) — cumulative cancer incidence ~40% by age 50.
- Androgen therapy (oxymetholone ± G-CSF) is first-line pharmacological treatment for cytopenias; haematopoietic stem cell transplant (SCT) remains the only curative option for bone marrow failure and myelodysplasia/leukaemia.
- SCT outcomes are best with an HLA-matched sibling donor using reduced-intensity conditioning (RIC) regimens to minimise transplant-related mortality.
- Lifelong cancer surveillance is mandatory: annual ENT examination from age 10, gynaecological screening from menarche, and screening colonoscopy from age 35 (or 10 years post-SCT).
- All patients require genetic counselling; sibling screening with chromosomal breakage testing is essential.
- Oxymetholone is PBS-listed (Authority Required) for aplastic anaemia in Australia; G-CSF (filgrastim) is PBS-listed as General Benefit for congenital neutropaenia and bone marrow failure.
- Aboriginal and Torres Strait Islander patients may present later due to reduced access to specialist and genetic services; culturally appropriate engagement and remote telehealth support are essential.
- Female patients require gynaecological and obstetric input — gonadal insufficiency is near-universal; oestrogen replacement is indicated for delayed puberty and bone protection.
Introduction & Australian Epidemiology
Fanconi anaemia (FA) is a rare, clinically heterogeneous inherited bone marrow failure syndrome characterised by defective DNA interstrand crosslink (ICL) repair. First described by Swiss paediatrician Guido Fanconi in 1927, FA is now understood to arise from biallelic (or, in the case of FANCB, hemizygous X-linked) pathogenic variants in one of at least 22 DNA repair genes that converge on a common pathway for resolving interstrand crosslinks and maintaining genomic stability.
FA has a worldwide incidence of approximately 1 in 160,000 live births, with an estimated heterozygous carrier frequency of 1 in 180–300 in outbred populations. Certain founder mutations substantially increase prevalence in specific populations: the Ashkenazi Jewish population (FANCC c.456+4A>T carrier frequency ~1 in 89), Afrikaner populations in South Africa (FANCG), and Spanish Romani communities (FANCA).
In Australia, FA accounts for a significant proportion of inherited bone marrow failure syndromes referred to tertiary paediatric haematology centres. The Royal Children's Hospital Melbourne, Sydney Children's Hospital, and the Women's and Children's Hospital Adelaide are the principal diagnostic and transplant centres. Australian data from the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) confirm approximately 2–4 SCT procedures for FA per year nationally. No specific Australian FA registry exists, though patients are captured by the ABMTRR and state-based genetics services.
The clinical course is dominated by progressive bone marrow failure, developmental anomalies, extreme cancer predisposition, and endocrine complications. Management requires a multidisciplinary team including paediatric haematology, genetics, endocrinology, ENT, gynaecology, and long-term adult survivorship care.
Genetics & DNA Repair Defect
The FA pathway is a complex signalling and repair network essential for resolving DNA interstrand crosslinks (ICLs) that would otherwise stall replication forks and cause chromosomal breakage. The pathway involves at least 22 complementation groups:
| Gene | Protein | Inheritance | Relative Frequency |
|---|---|---|---|
| FANCA | FANCA | AR | ~60–65% |
| FANCC | FANCC | AR | ~10–15% |
| FANCG | FANCG/XRCC9 | AR | ~10% |
| FANCD2 | FANCD2 | AR | ~3% |
| FANCJ/BRIP1 | BRIP1 | AR | ~2% |
| FANCB | FANCB | X-linked | ~2% |
| FANCD1/BRCA2 | BRCA2 | AR | ~2–3% |
| FANCN/PALB2 | PALB2 | AR | ~1–2% |
| Others (FANCL, FANCM, FANCO, FANCP, FANCQ, FANCR, FANCS, FANCT, FANCU, FANCV, FANCW) | Various | AR | ~5% combined |
FANCD1 (BRCA2) and FANCN (PALB2): Patients with biallelic BRCA2 or PALB2 mutations have extremely severe phenotypes with very early-onset AML and embryonal tumours (Wilms tumour, medulloblastoma). These children require urgent SCT referral and intensive oncological surveillance from infancy.
Molecular Pathway
The FA core complex (FANCA, B, C, E, F, G, L, M, T) functions as an E3 ubiquitin ligase that monoubiquitinates the FANCI–FANCD2 (ID2) complex upon replication fork stalling at an ICL. Ubiquitinated ID2 recruits downstream effectors including FANCD1 (BRCA2), FANCJ (BRIP1), FANCN (PALB2), FANCO (RAD51C), FANCS (BRCA1), and FANCR (RAD51) for homologous recombination repair. Deficiency at any step leads to accumulation of unrepaired ICLs, chromosomal breakage, chromosomal instability, and cell death — particularly in haematopoietic stem and progenitor cells.
Inheritance & Genetic Counselling
- Autosomal recessive for all groups except FANCB (X-linked recessive — all affected individuals are male).
- Recurrence risk for siblings: 25% affected, 50% carrier, 25% unaffected non-carrier (for AR forms).
- Siblings of affected probands should undergo chromosomal breakage testing regardless of phenotype.
- Carrier testing and prenatal/pre-implantation genetic diagnosis (PGD) are available at Australian genetics centres (e.g., Victorian Clinical Genetics Services, NSW Health Pathology Genetics).
- Somatic mosaicism (revertant mosaicism) occurs in 10–25% of FA patients and may confound diagnostic testing.
Clinical Features & Congenital Anomalies
FA exhibits wide phenotypic variability even within families carrying identical mutations. Approximately 60–75% of patients have at least one congenital anomaly; however, up to 30% appear phenotypically normal at birth, leading to delayed diagnosis.
Congenital Anomalies
| System | Anomalies | Frequency |
|---|---|---|
| Skeletal — upper limb | Radial ray defects (hypoplastic/absent thumbs, radial aplasia), thenar hypoplasia | 40–50% |
| Skin | Generalised hyperpigmentation, café-au-lait spots, hypopigmented patches | 50–60% |
| Growth | Short stature (proportionate), low birth weight | 50–65% |
| Craniofacial | Microcephaly, micrognathia, small eyes, epicanthic folds, ear anomalies | 30–50% |
| Renal | Horseshoe kidney, renal agenesis, duplicated collecting system, renal hypoplasia | 20–30% |
| Genitourinary | Hypogonadism, hypospadias, undescended testes, bicornuate uterus, vaginal atresia | 15–30% |
| Eyes | Strabismus, cataracts, microphthalmia, ptosis | 10–25% |
| GI/hepatic | Oesophageal atresia, tracheo-oesophageal fistula, biliary atresia | 5–10% |
| Cardiac | VSD, ASD, PDA, coarctation of the aorta | 5–10% |
| CNS | Structural CNS malformations, developmental delay (mild) | 5–10% |
| Hearing | Sensorineural or conductive hearing loss | 5–10% |
VACTERL-H Association
FA is an important differential diagnosis in any child with features of VACTERL-H (Vertebral, Anal, Cardiac, Tracheo-Esophageal, Renal, Limb anomalies + Hydrocephalus). All children with radial ray anomalies or VACTERL-H should be screened with a chromosomal breakage test.
Haematological Manifestations
- Median age at diagnosis of bone marrow failure: 7 years (range birth to 40+ years).
- Thrombocytopaenia is often the first cytopenia detected, followed by neutropaenia and then anaemia.
- Progressive macrocytosis (elevated HbF, raised MCV) is an early haematological clue even before overt cytopenias.
- ≥80% of patients develop clinically significant bone marrow failure by age 40.
- Myelodysplastic syndrome (MDS) occurs in 20–30% and may progress to AML.
Endocrine Manifestations
- Growth hormone deficiency and hypothyroidism are common.
- Gonadal insufficiency: primary ovarian insufficiency in females; testicular failure in males.
- Insulin resistance and glucose intolerance develop in a significant proportion of adults.
- Reduced bone mineral density — compounded by chronic corticosteroid or androgen therapy.
Investigations (Chromosomal Fragility Test)
Diagnostic Testing
Essential
Chromosomal breakage test (DEB/MMC)
Gold-standard diagnostic assay. Peripheral blood lymphocytes are cultured with phytohaemagglutinin and exposed to diepoxybutane (DEB) or mitomycin C (MMC). FA cells show dramatically increased chromosomal breakage (radial figures, triradials, quadriradials). Sensitivity and specificity >97%. Available at Royal Children's Hospital Melbourne, SA Pathology Genetics, and NSW Health Pathology. Turnaround: 3–4 weeks. Request requires haematology/genetics referral.
Specialist
FANCD2 ubiquitination assay (flow cytometry)
Functional assay measuring monoubiquitination of FANCD2 by Western blot or flow cytometry. Useful as an adjunct or when chromosomal breakage is equivocal. Available at research laboratories (e.g., Peter MacCallum Cancer Centre). Turnaround: 2–4 weeks.
Specialist
FA-targeted gene panel / next-generation sequencing
Identifies the specific causative gene variant. Essential for genetic counselling, prenatal testing, and family studies. Available through Victorian Clinical Genetics Services (VCGS), SA Pathology, and Sonic Healthcare genetics. Commercial panels (Invitae, Prevention Genetics) also available via referral. Turnaround: 4–8 weeks.
Available
Full blood count + blood film
Macrocytosis (elevated MCV), progressive bicytopenia or pancytopenia. Blood film may show macro-ovalocytes, teardrop cells, and hypogranular neutrophils suggestive of MDS. MBS Item 65070.
Available
Haemoglobin F quantification
Elevated HbF for age is common in FA and may be an early marker of clonal haematopoiesis/MDS. MBS Item 65095 (haemoglobin electrophoresis).
Available
Bone marrow aspirate + trephine biopsy
Essential at diagnosis and for MDS/AML surveillance. Assess cellularity, dysplasia, blast percentage, and cytogenetics (conventional karyotype + FISH). Perform when cytopenias are progressive or new morphological changes appear.
Available
Renal ultrasound
Screen for structural renal anomalies at diagnosis. Repeat if clinically indicated.
Available
Endocrine panel
Thyroid function (TSH, fT4), IGF-1 (growth hormone axis), glucose/HbA1c, insulin, oestradiol/testosterone, LH, FSH, bone densitometry (DEXA). MBS Items: 66647 (TSH), 66812 (IGF-1).
Available
MRI brain
Screen for structural CNS anomalies at diagnosis. MBS Item 63001.
Available
Echocardiogram
Screen for congenital cardiac anomalies. MBS Item 55124.
Interpretation pitfalls: The chromosomal breakage test may be falsely normal in patients with somatic mosaicism (revertant mosaicism), which occurs in 10–25% of FA patients. If clinical suspicion is high despite a normal DEB/MMC test, consider FANCD2 ubiquitination assay and gene panel sequencing. Pregnancy may also cause false-negative results due to maternal cell contamination in prenatal samples.
MBS Item Summary for Key Investigations
| Investigation | MBS Item | Notes |
|---|---|---|
| FBC + blood film | 65070 | Serial monitoring essential |
| Hb electrophoresis | 65095 | Elevated HbF for age |
| TSH, fT4 | 66647 | Screen at diagnosis, annually |
| IGF-1 | 66812 | GH deficiency screening |
| Echocardiogram | 55124 | Structural anomaly screening |
| Renal ultrasound | 55300 | Structural anomaly screening |
| MRI brain | 63001 | CNS anomaly screening |
Management (Androgens, SCT, Surveillance)
Androgen Therapy
Androgens stimulate erythropoiesis and can produce meaningful haematological responses in FA patients with cytopenias. They are first-line pharmacological therapy when SCT is not immediately indicated.
Oxymetholone
Anapolon® · Androgenic anabolic steroid
Adult dose
1–2 mg/kg/day PO in divided doses (typically 25–50 mg daily), titrate to response
Paediatric dose
1–5 mg/kg/day PO; start low (1–2 mg/kg/day) and titrate; monitor closely for hepatotoxicity
Route
Oral
Duration
Indefinite while responsive; reassess every 3–6 months
Key monitoring
LFTs (ALT, AST, GGT) every 3 months; hepatic peliosis risk; lipid profile; bone age in children; peliosis hepatis — discontinue if hepatic dysfunction develops
Renal adjustment
No specific dose adjustment; monitor hepatic and renal function concurrently
Hepatic adjustment
Contraindicated in severe hepatic impairment; withhold if hepatic peliosis suspected
PBS status
✔ PBS Authority Required — for aplastic anaemia
Danazol
Danocrine® · Attenuated androgen
Adult dose
200–800 mg/day PO in divided doses
Paediatric dose
5–10 mg/kg/day PO; limited paediatric data
Notes
Alternative to oxymetholone; possibly fewer virilising effects; similar hepatotoxicity profile
PBS status
✘ Not PBS listed for this indication
Filgrastim
Neupogen® / Zarzio® · G-CSF
Adult dose
5 mcg/kg/day SC; titrate to maintain ANC >1.0 × 10⁹/L
Paediatric dose
5–10 mcg/kg/day SC
Notes
Used in combination with androgens for severe neutropaenia or recurrent infections; does not reverse the underlying stem cell defect; theoretical concern regarding clonal evolution — use at lowest effective dose and monitor with serial bone marrow cytogenetics
PBS status
✔ PBS General Benefit — for congenital neutropaenia
Androgen toxicity: Oxymetholone carries a significant risk of peliosis hepatis (blood-filled hepatic cysts), hepatocellular adenoma, and cholestatic hepatitis. Monitor LFTs every 3 months. Discontinue immediately if ALT rises >3× ULN or hepatic peliosis is suspected on imaging. Virilisation, premature epiphyseal closure in children, dyslipidaemia, and mood changes are also important adverse effects.
Haematopoietic Stem Cell Transplantation (SCT)
SCT is the only curative treatment for FA-related bone marrow failure and myelodysplasia/AML. However, FA cells are exquisitely sensitive to alkylating agents and ionising radiation, necessitating modified transplant conditioning regimens.
Preferred
HLA-matched sibling donor SCT
Best outcomes — 3-year survival 80–90% with RIC regimens. Indicated when marrow failure is progressive (transfusion-dependent, severe neutropaenia) or MDS/AML develops.
Setting: Tertiary transplant centre (RCH Melbourne, SCH, WCH Adelaide)
Alternative
Matched unrelated donor (MUD) SCT
3-year survival 50–70%. Outcomes improving with better HLA typing and RIC. Indicated when no matched sibling donor is available and transplant is clinically indicated.
Setting: Tertiary transplant centre; coordinate with ABMTRR and Bone Marrow Donor Registry (BMDI)
Last resort
Haploidentical / cord blood SCT
Higher TRM; reserved for patients without matched donors. Post-transplant cyclophosphamide-based platforms show improving results. Outcomes remain inferior to matched donor transplants.
Setting: Selected specialist centres with haploidentical transplant expertise
Conditioning regimen considerations: Reduced-intensity conditioning (RIC) with fludarabine, low-dose cyclophosphamide, and low-dose busulfan (or total body irradiation ≤300 cGy) is standard. Full-intensity myeloablative conditioning is contraindicated in FA due to excessive toxicity and TRM. Anti-thymocyte globulin (ATG) is commonly included for immunosuppression and to promote engraftment.
Transplant Indications
- Transfusion-dependent thrombocytopaenia or anaemia unresponsive to androgens.
- Severe neutropaenia (ANC <0.5 × 10⁹/L) with recurrent life-threatening infections.
- Progressive MDS with increasing blast count or adverse cytogenetics (monosomy 7, complex karyotype).
- Evolution to AML.
- Early transplant with a matched sibling donor before severe marrow failure may be considered in selected cases.
Cancer Surveillance Programme
FA patients have a cumulative lifetime cancer risk of approximately 40% by age 50. Head and neck squamous cell carcinoma (HNSCC) and anogenital squamous cell carcinoma are particularly over-represented, with risk further increased post-SCT due to conditioning-related mucosal damage and chronic GVHD.
From age 10
Annual ENT examination including oral cavity, oropharynx, and nasopharynx inspection; direct laryngoscopy if suspicious lesions identified. Teach patients self-examination of oral mucosa.
From menarche / age 16
Annual gynaecological examination with vulvar and vaginal visual inspection; cervical screening (HPV-based from age 25 per Australian guidelines); consider vaginal swabs for HPV typing.
From age 18
Annual head and neck examination; low threshold for biopsy of any mucosal lesion. Educate regarding alcohol and smoking avoidance (synergistic carcinogen risk).
From age 35 (or 10 years post-SCT)
Screening colonoscopy every 3–5 years. Earlier if GI symptoms or family history of colorectal cancer.
Ongoing
Annual FBC + blood film; bone marrow aspirate + cytogenetics annually (or more frequently if MDS identified). Hepatic ultrasound annually if on androgen therapy. Renal ultrasound if structural anomalies identified. Endocrine monitoring: thyroid, glucose, bone densitometry annually.
Post-transplant cancer risk: SCT does not reduce cancer risk — HNSCC risk is increased post-transplant, particularly in patients with chronic GVHD and/or those who received irradiation-based conditioning. Lifelong cancer surveillance must continue regardless of transplant status. Avoid smoking and alcohol absolutely.
Supportive Care
- Infection prevention: Irradiated, CMV-safe blood products for all transfusions (FA cells are hypersensitive to allogeneic lymphocytes). Leucodepleted products as standard. Pneumocystis jirovecii prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) when neutropaenic.
- Iron chelation: Deferasirox (Jadenu® — PBS Authority Required) or deferoxamine if transfusional iron overload develops. Target ferritin <500 mcg/L.
- Oestrogen replacement: For female patients with primary ovarian insufficiency — physiological oestradiol with cyclic progesterone. Important for bone health, cardiovascular protection, and quality of life.
- Growth hormone: Recombinant GH (somatropin — PBS Authority Required) if documented GH deficiency and significant growth impairment.
- Psychosocial support: Referral to clinical psychology; peer support groups (Fanconi Anemia Research Fund — FARF); consideration of genetic counselling for the extended family.
- Pregnancy management: Pregnancy is possible in some female patients (especially after oestrogen replacement). High-risk obstetric care is recommended — increased risk of pre-eclampsia, preterm delivery, and small-for-gestational-age infants. Avoid teratogenic agents.
Special Populations
Paediatrics
Diagnosis may be delayed in phenotypically normal children — screen any child with idiopathic aplastic anaemia, VACTERL-H, or unexplained macrocytosis.
Bone age monitoring essential if androgens used — premature epiphyseal fusion risk. Consider aromatase inhibitor adjunct in selected cases.
Growth hormone therapy for documented GH deficiency — coordinate with paediatric endocrinology.
SCT should ideally be performed in childhood when matched sibling donor is available, before severe marrow failure develops.
Pregnancy
Androgens are absolutely contraindicated in pregnancy (teratogenic — virilisation of female foetus).
Pregnancy should be planned in consultation with haematology and obstetric medicine — optimise cytopenias pre-conception.
High-risk obstetric surveillance for pre-eclampsia, foetal growth restriction, preterm labour.
Irradiated blood products required throughout pregnancy and for any transfusions.
Adult Survivorship
Transition from paediatric to adult haematology care is critical — ensure cancer surveillance programme is maintained.
Screen for metabolic syndrome, insulin resistance, and osteoporosis.
Manage endocrine sequelae: thyroid, gonadal, adrenal, and GH axes.
Renal Impairment
Congenital renal anomalies present in 20–30% — monitor renal function at baseline and periodically.
Deferasirox dose adjustment required for eGFR <40 mL/min — switch to deferoxamine.
Renal dosing for SCT conditioning agents must be carefully adjusted.
Hepatic Impairment
Androgen therapy carries risk of peliosis hepatis — regular LFT monitoring essential (every 3 months).
Discontinue oxymetholone if hepatic dysfunction develops. Consider danazol as alternative (similar hepatotoxicity profile).
Hepatic ultrasound annually while on androgens.
Immunocompromised
Neutropaenia prophylaxis: TMP-SMX for PJP; consider antifungal prophylaxis (fluconazole/posaconazole) during severe neutropaenia.
Live vaccines contraindicated during immunosuppressive therapy or post-SCT.
Post-SCT: follow transplant unit immunisation re-vaccination schedule.
ATSI Health Considerations
Aboriginal and Torres Strait Islander Health
📚 References
- 1. Duxin JP, Walter JC. What is the DNA repair defect underlying Fanconi anemia? Curr Opin Cell Biol. 2015;37:49–60.
- 2. Nalepa G, Clapp DW. Fanconi anaemia and cancer: an intricate relationship. Nat Rev Cancer. 2018;18(3):168–185.
- 3. Alter BP. Diagnosis, genetics, and management of inherited bone marrow failure syndromes. Hematology Am Soc Hematol Educ Program. 2007;2007:29–39.
- 4. Soulier J. Fanconi anemia. Hematology Am Soc Hematol Educ Program. 2011;2011:492–497.
- 5. Ebens CL, MacMillan ML, Wagner JE. Hematopoietic cell transplantation in Fanconi anemia: current evidence and challenges. Hematol Oncol Clin North Am. 2018;32(4):713–727.
- 6. Peake JD, Noguchi E. Fanconi anemia: current insights regarding epidemiology, cancer, and DNA repair. Hum Genet. 2022;141(12):1841–1859.
- 7. Australian Institute of Health and Welfare (AIHW). Aboriginal and Torres Strait Islander health performance framework 2023. Canberra: AIHW; 2023.
- 8. Kutler DI, Singh B, Satagopan J, et al. A 20-year perspective on the International Fanconi Anemia Registry (IFAR). Blood. 2003;101(4):1249–1256.
- 9. Rosenberg PS, Tamary H, Alter BP. How high are carrier frequencies of rare recessive syndromes? Contemporary estimates for Fanconi anemia in the United States and Israel. Am J Med Genet A. 2011;155A(8):1877–1883.
- 10. Mehta PA, Tolar J. Fanconi anemia. In: Adam MP, Mirzaa GM, Pagon RA, et al., editors. GeneReviews®. Seattle: University of Washington; 2024.
- 11. Australasian Bone Marrow Transplant Recipient Registry (ABMTRR). Annual Report 2023. Sydney: ABMTRR; 2023.
- 12. Savage SA, Dufour C. Classical inherited bone marrow failure syndromes with high risk for myelodysplastic syndrome and acute myelogenous leukemia. Semin Hematol. 2017;54(2):105–114.
- 13. Savage SA. Connecting Fanconi anemia with head and neck cancer. Clin Cancer Res. 2019;25(24):7258–7260.
- 14. Pagliuca S, Gurnari C, Hercus C, et al. The molecular landscape of Fanconi anemia: insights from genomics. Leukemia. 2023;37(5):991–1003.