Diagnosis guide for clinicians
Fabry disease: when to suspect it and what to test
Fabry disease is an X-linked lysosomal disorder in which deficient alpha-galactosidase A activity lets globotriaosylceramide and its derivatives build up in cells throughout the body.GeneReviews
GeneReviews notes that later-onset forms are more common than the classic phenotype, present later in life and are underdiagnosed, with delays particularly common in females.GeneReviews
A French expert consensus reports a delay from first symptoms to diagnosis of 13.7 years in males and 16.3 years in females.French pediatric consensus
Red flags for Fabry disease
What the cited sources describe, grouped by life stage and organ. Each line links to its source.
Childhood (classic phenotype)
- Crises of burning pain in the hands and feet (acroparesthesia), often triggered by exercise, fatigue, emotional stress or rapid changes in temperature and humidity.GeneReviews
- Pain felt in the palms, soles and fingertips during the day, often in late morning, rather than leg pain in the evening or night.French pediatric consensus
- Reduced or absent sweating, with intolerance of heat, cold or exercise.French pediatric consensus
- Recurrent abdominal pain and diarrhea, with a reported median onset of 5 years in boys and 9.5 years in girls.French pediatric consensus
- Fatigue, school absences, hearing loss and tinnitus alongside pain.French pediatric consensus
- GeneReviews says boys generally present with the classic phenotype from age 3 to 5 years.GeneReviews
Adolescence and young adulthood
- Angiokeratomas: clusters of dark red to blue-black spots that do not blanch, densest between the umbilicus and knees; checking the skin, especially the scrotum and umbilicus, may reveal isolated lesions.GeneReviews
- Cornea verticillata on slit-lamp examination, seen in affected males and most heterozygous females; it does not affect visual acuity.GeneReviews
- Abdominal pain, nausea or diarrhea of unknown cause in young adulthood that fits irritable bowel syndrome.GeneReviews
- Unexplained proteinuria or microalbuminuria; in childhood and adolescence the urine sediment may show lipid globules with Maltese crosses.GeneReviews
- High-frequency hearing loss, tinnitus and dizziness from vestibular involvement.GeneReviews
Adulthood: heart, kidney and brain (classic and later-onset)
- Unexplained left ventricular hypertrophy or arrhythmia, including a short PR interval and conduction abnormalities.GeneReviews
- Later-onset cardiac disease typically presents in the sixth to eighth decade with LVH resembling hypertrophic cardiomyopathy and posterior wall late gadolinium enhancement.GeneReviews
- Unexplained stroke or transient ischemic attack, with white matter lesions often seen on brain MRI.GeneReviews
- Kidney disease of unknown cause, including patients on dialysis whose kidney failure was attributed to chronic glomerulonephritis.GeneReviews
- The renal variant may lack early classic signs; five of six patients in one Japanese dialysis series had no angiokeratoma, acroparesthesia, hypohidrosis or corneal opacities.GeneReviews
- A Turkish multidisciplinary panel names LVH, end-stage kidney disease, cryptogenic stroke and small-fiber neuropathy as high-risk groups.Turkish multidisciplinary expert opinion
Women and heterozygous females
- Manifestations range from none across a normal life span to disease as severe as in males, which GeneReviews attributes to random X-chromosome inactivation.GeneReviews
- Reported frequencies in heterozygotes: cornea verticillata 70% to 90%, acroparesthesia 50% to 90% and sparse angiokeratomas 10% to 50%.GeneReviews
- Females may develop myocardial fibrosis without apparent LVH.GeneReviews
- About 10% of heterozygotes develop kidney failure needing dialysis or transplantation, according to US and European registries cited by GeneReviews.GeneReviews
- MedlinePlus Genetics notes that, unlike many X-linked disorders, Fabry disease causes significant medical problems in many females with one altered GLA copy.MedlinePlus Genetics
- Italian experts write that females tend to ignore their symptoms, and clinicians often misunderstand or discount them.Italian expert opinion on females
Family history
- An X-linked pattern with no male-to-male transmission; absence of a known family history does not preclude the diagnosis.GeneReviews
- Relatives with cardiomyopathy, chronic kidney disease, stroke or unexplained early death.European Heart Journal LVH review
- Family members, especially males, who died before age 50 from stroke, arrhythmia, conduction disease or kidney failure.French pediatric consensus
Often mistaken for
Diagnoses patients commonly carry first, and why the sources say they are confused.
| First diagnosis | Why it is confused |
|---|---|
| Growing pains | Limb pain in children is common; Fabry pain is burning or tingling in the hands and feet by day, while growing pains usually affect the legs at night.French pediatric consensus |
| Rheumatic fever, juvenile or rheumatoid arthritis | Joint or limb pain can come with fever and a raised erythrocyte sedimentation rate.Turkish multidisciplinary expert opinion |
| Irritable bowel syndrome | Episodic diarrhea, cramping, bloating and nausea; GeneReviews cites IBS-like symptoms in nearly 20% of the Fabry Registry.GeneReviews |
| Other gastrointestinal dysmotility disorders | A gastroenterology review says the dysmotility symptoms are shared with many disorders and can be misdiagnosed by gastroenterologists for many years.Gastroenterology review |
| Multiple sclerosis | Both can cause attacks of limb pain under heat, stress or fatigue, plus white matter lesions on MRI.Turkish multidisciplinary expert opinion |
| Hypertrophic cardiomyopathy | Fabry LVH can look like HCM; one screening study cited in the European Heart Journal found Fabry disease in about 1% of 508 'HCM' patients.European Heart Journal LVH review |
| Chronic glomerulonephritis or kidney failure of unknown cause | Renal variants were found among Japanese dialysis patients whose kidney failure had been called chronic glomerulonephritis.GeneReviews |
| Appendicitis or renal colic | Attacks of abdominal or flank pain may simulate both.GeneReviews |
| Raynaud syndrome | Pain and abnormal thermal sensitivity in the extremities.Turkish multidisciplinary expert opinion |
| Lupus, autoimmune disease or petechiae | The Turkish panel links both misdiagnoses to angiokeratomas.Turkish multidisciplinary expert opinion |
| Neurosis or malingering | Unexplained episodes of acute pain.Turkish multidisciplinary expert opinion |
Codes patients often carry before this diagnosis
For spotting the pattern in a problem list or registry. Descriptions are checked daily against NLM's ICD-10-CM service; this is not coding advice.
I42.1, I42.2Unexplained left ventricular hypertrophy or a hypertrophic cardiomyopathy label is a common first cardiac finding in later-onset Fabry disease.GeneReviews
N18.1, N18.2, N18.30, N18.31, N18.32, N18.4, N18.5, N18.9Kidney decline, often with proteinuria, is a core Fabry manifestation and can lead to kidney failure.GeneReviews
R80.0, R80.1, R80.8, R80.9Protein in the urine is among the early kidney signs listed for Fabry disease.GeneReviews
H18.031, H18.032, H18.033, H18.039Cornea verticillata, the whorl-shaped corneal deposits an eye doctor sees on slit-lamp examination, is common in affected males and most heterozygous females.GeneReviews
What to test, step by step
The testing order the cited guidance describes, by who it applies to. It summarizes published guidance and is not a plan for any one patient.
Males with suspected Fabry disease
- Alpha-Gal A enzyme activity
Deficient activity in plasma, isolated leukocytes and/or cultured cells establishes the diagnosis in a male. Classic males have under 1% activity; males with atypical disease have more than 1%.GeneReviews
Males
- Assay plasma and leukocytes
GeneReviews advises assaying both, because some variants such as p.Asn215Ser lower plasma activity more than leukocyte activity.GeneReviews
- GLA sequencing after low enzyme activity
The same panel says enzyme testing alone is diagnostic in males, but GLA testing establishes the phenotype and rules out benign polymorphisms.Turkish multidisciplinary expert opinion
Males screened by dried blood spot
- Confirm a dried blood spot result
A Sanofi-supported Turkish panel says a positive spot result, or a negative one in a highly suspected patient, should be confirmed by leukocyte enzyme activity or genetic testing.Turkish multidisciplinary expert opinion
Females with suspected Fabry disease
- GLA sequencing as the diagnostic test
Diagnosis in a female rests on a heterozygous pathogenic or likely pathogenic GLA variant. GeneReviews calls enzyme activity unreliable in heterozygotes, because some have activity in the normal range.GeneReviews
Females
- Limits of enzyme and lyso-Gb3 in females
Italian experts, in a Sanofi-funded paper, advise against using alpha-Gal A activity or plasma lyso-Gb3 to diagnose females, citing low sensitivity. They add that normal lyso-Gb3 cannot exclude the disease, especially with a VUS.Italian expert opinion on females
Anyone with no variant found by sequencing
- Deletion/duplication analysis
GeneReviews lists gene-targeted deletion/duplication analysis as the next step when sequencing finds no variant, since some methods miss exon or whole-gene changes.GeneReviews
Males and females
- Plasma lyso-Gb3 as a supporting biomarker
GeneReviews says lyso-Gb3 is higher in affected males than females and helps separate classic from later-onset phenotypes. It also states there are no universally recognized biomarkers of Fabry disease.GeneReviews
People with atypical features in whom Fabry disease was not considered
- Exome or genome sequencing
GeneReviews calls comprehensive genomic testing the best option when atypical features kept Fabry disease from being considered; exome sequencing is most common.GeneReviews
Anyone with a GLA VUS
- Variant of uncertain significance: what it means
A hemizygous or heterozygous GLA VUS neither establishes nor rules out the diagnosis. GeneReviews cites a study where people with a novel variant and organ involvement had lyso-Gb3 at or above 2.7ng/mL.GeneReviews
- Variant of uncertain significance: further evidence
A Sanofi-funded European expert group lists family segregation, findings in male relatives, imaging, kidney or skin biopsy and expert consultation as ways to confirm or exclude pathogenicity.European consensus on females
Adults with LVH over 12mm and a GLA VUS
- VUS with unexplained LVH
A Delphi consensus names endomyocardial biopsy with electron microscopy as the gold standard. It lists abnormally low ECG voltages and severe LVH over 15mm before age 20 as findings that exclude Fabry disease.Delphi consensus on LVH and VUS
Uncertain enzyme or genetic results
- Tissue biopsy only for unclear cases
GeneReviews says biopsy is not usually required. Kidney biopsy with electron microscopy is often diagnostic in unexplained kidney failure.GeneReviews
Adults being considered for Galafold
- Amenability check before migalastat
The Galafold label indicates it for adults with confirmed Fabry disease and an amenable GLA variant based on in vitro assay data. The amenable variant must be interpreted by a clinical genetics professional as pathogenic or likely pathogenic.Galafold label
Where testing goes wrong
- A normal alpha-Gal A result in a woman does not exclude Fabry disease, because some heterozygotes have activity in the normal range.GeneReviews
- A European Heart Journal review reports normal or low-normal enzyme activity in up to one-third of females with Fabry disease.European Heart Journal LVH review
- Measuring leukocyte activity alone can understate the deficiency for variants such as p.Asn215Ser, which reduce plasma activity more.GeneReviews
- Routine sequencing cannot detect deletions or duplications in females; Italian experts recommend adding an allelic dosage assay such as MLPA.Italian expert opinion on females
- Dried blood spot enzyme assays can give false positive or false negative results unless confirmed by a second-tier test.Turkish multidisciplinary expert opinion
- Variants such as p.D313Y and p.E66Q, and probably p.R118C, are described as polymorphisms with high residual activity, not disease-causing variants.Turkish multidisciplinary expert opinion
- Variant calls can change; GeneReviews cites cardiac pedigree data supporting pathogenicity of p.Ala143Thr, a variant earlier reported as benign.GeneReviews
- A 2019 French consensus lists p.Ala143Thr among benign or likely benign variants that should not be considered causative, so sources still disagree on it.French pediatric consensus
- Amiodarone and chloroquine can produce corneal opacities that look like cornea verticillata.Turkish multidisciplinary expert opinion
- Hydroxychloroquine can mimic Fabry zebra bodies on kidney biopsy electron microscopy.GeneReviews
- A Turkish panel links testing when only one sign is present to more samples, fewer positive results and more variants of unknown clinical relevance.Turkish multidisciplinary expert opinion
- Angiokeratomas are not specific; Fordyce, Mibelli and circumscriptum types and other lysosomal disorders can look similar.GeneReviews
Where to test
- NIH Genetic Testing Registry: Fabry disease: Lists clinical enzyme assays, analyte tests, GLA sequencing and deletion/duplication tests submitted by laboratories. NIH does not independently verify submissions or endorse any laboratory.NIH GTR
- GTR search: clinical tests for Fabry disease: Searchable list of clinical tests submitted by laboratories, filterable by method such as enzyme assay or sequence analysis. The number of listed tests changes as laboratories add or retire them.NIH GTR
- NIH's Genetic Testing Registry listed 172 tests for a search of “Fabry disease” on November 9, 2026. NIH does not endorse or verify the labs it lists.
Family screening and referral
Who else in the family
- An affected male passes the GLA variant to all of his daughters and none of his sons.GeneReviews
- A heterozygous female has a 50% chance of passing the variant in each pregnancy.GeneReviews
- When a male is the only affected family member, his mother is likely heterozygous; rarely the variant arose de novo.GeneReviews
- Relatives are tested for the known family GLA variant; if it is unknown, enzyme activity can screen male relatives only.GeneReviews
- A French consensus calls screening children with a first-degree relative with Fabry disease the simplest and fastest way to improve diagnosis.French pediatric consensus
- The same group says predictive testing of children of affected parents is justified under European Society of Human Genetics guidelines.French pediatric consensus
- Italian experts advise building a pedigree and screening all at-risk female relatives of an index case.Italian expert opinion on females
- Prenatal and preimplantation genetic testing are possible once the family variant is identified.GeneReviews
Who to refer to
- A Turkish panel says cardiologists, neurologists, dermatologists, nephrologists and ophthalmologists should all be aware of Fabry disease.Turkish multidisciplinary expert opinion
- After diagnosis, the same panel advises the opinion of a pediatric metabolic physician or a pediatric or medical geneticist, plus family screening.Turkish multidisciplinary expert opinion
- For a VUS, it advises expert review in pediatric metabolic disease or pediatric or medical genetics.Turkish multidisciplinary expert opinion
- Adult recommendations in Molecular Genetics and Metabolism call for management by an experienced multidisciplinary team.Adult management recommendations
- The French pediatric consensus names a pediatrician, geneticist and pain specialist as the core team.French pediatric consensus
- The Galafold label strongly recommends a clinical genetics professional when an amenable variant is a VUS or may be benign.Galafold label
- GARD suggests a multidisciplinary care center or university hospital when a diagnosis remains unclear.GARD
Find a specialist by state
From the CMS NPI Registry, a public directory of US clinicians by registered specialty. A listing is not an endorsement and says nothing about experience with Fabry disease; patient organizations and academic centers can often name experienced clinicians.
ICD-10-CM codes for Fabry disease
For orders, referrals and prior authorization. Each code is checked daily against NLM's ICD-10-CM service.
Once the diagnosis is confirmed
For the patient: why your doctor ordered this test
Plain language a patient can read or take home.
Your doctor ordered this test because some of your symptoms can be a sign of Fabry disease. It is a rare illness that runs in families.
With Fabry disease, the body cannot break down a type of fat. The fat builds up in the kidneys, heart, nerves and skin.
A blood test can check the level of an enzyme. A gene test looks for a change in a gene called GLA.
Women with Fabry disease can have a normal enzyme level. That is why doctors often use the gene test for women.
Sometimes the test finds a gene change that no one fully understands yet. Your doctor may then suggest more tests or a visit with a genetics expert.
If you have Fabry disease, your parents, brothers, sisters and children may also need testing, even if they feel fine.
Questions clinicians ask about Fabry disease testing
What test confirms Fabry disease in a male?
Deficient alpha-galactosidase A activity in plasma, leukocytes or cultured cells establishes the diagnosis in a male, per GeneReviews (revised April 11, 2024). GeneReviews advises assaying both plasma and leukocytes. A hemizygous pathogenic GLA variant confirms the diagnosis and names the variant. A Sanofi-supported Turkish panel adds that GLA testing establishes the phenotype and rules out benign polymorphisms.
Can a woman have Fabry disease with normal enzyme activity?
Yes; GeneReviews says some heterozygous females have alpha-Gal A activity in the normal range. Diagnosis in a female therefore rests on a pathogenic or likely pathogenic GLA variant. Italian experts, in a Sanofi-funded paper, add that a normal plasma lyso-Gb3 does not exclude the disease either.
How is a GLA variant of uncertain significance handled in Fabry disease?
A VUS neither establishes nor rules out Fabry disease, per GeneReviews. A Sanofi-funded European expert group lists family segregation, findings in male relatives, imaging, biopsy and genetics expert review as ways to clarify it. For LVH with a VUS, one Delphi consensus names endomyocardial biopsy as the gold standard.
Who should be screened for Fabry disease?
Relatives of a known patient and people with unexplained LVH, kidney failure, cryptogenic stroke or small-fiber neuropathy are the groups named in published expert reviews, including a Sanofi-supported Turkish panel. A Sanofi-funded French consensus calls screening children with a first-degree relative with Fabry disease the simplest and fastest way to improve diagnosis.
What is the ICD-10 code for Fabry disease?
The ICD-10-CM code is E75.21, Fabry (-Anderson) disease, per the National Library of Medicine's ICD-10-CM lookup checked November 8, 2026.
Sources
- Fabry Disease. GeneReviews, University of Washington, Seattle, via NCBI Bookshelf (NBK1292); Mehta A, Hughes DA, 2024-04-11.
- Consensus recommendations for diagnosis, management and treatment of Fabry disease in paediatric patients. Clinical Genetics (Germain DP et al; expert meetings and writing support funded by Sanofi-Genzyme), via PubMed Central, 2019-06-06.
- Clinical management of female patients with Fabry disease based on expert consensus. Orphanet Journal of Rare Diseases (Brand E et al; advisory board and writing support funded by Sanofi), via PubMed Central, 2025-01-07.
- Females with Fabry disease: an expert opinion on diagnosis, clinical management, current challenges and unmet needs. Frontiers in Cardiovascular Medicine (Tuttolomondo A et al; funded by Sanofi), via PubMed Central, 2025-03-12.
- Expert opinion on the recognition, diagnosis and management of children and adults with Fabry disease: a multidisciplinary Turkey perspective. Orphanet Journal of Rare Diseases (Ezgu F et al; supported by Sanofi Genzyme Turkey), via PubMed Central, 2022-03-02.
- Left ventricular hypertrophy in Fabry disease: a practical approach to diagnosis. European Heart Journal (Yousef Z et al; open access fee paid by Genzyme Europe), via PubMed Central, 2012-06-26.
- Understanding the gastrointestinal manifestations of Fabry disease: promoting prompt diagnosis. Therapeutic Advances in Gastroenterology (Zar-Kessler C et al; authors in a Genzyme-funded fellowship), via PubMed Central, 2016-04-15.
- Uncertain diagnosis of Fabry disease: consensus recommendation on diagnosis in adults with left ventricular hypertrophy and genetic variants of unknown significance. International Journal of Cardiology (Smid BE et al), via PubMed, 2014-09-20.
- Fabry disease revisited: Management and treatment recommendations for adult patients. Molecular Genetics and Metabolism (Ortiz A et al), via PubMed, 2018-02-28.
- Fabry disease: MedlinePlus Genetics. National Library of Medicine, 2022-07-29.
- Fabry disease | About the Disease | GARD. Genetic and Rare Diseases Information Center, NIH, 2026-09.
- Fabry disease - NIH Genetic Testing Registry (GTR) - NCBI. National Center for Biotechnology Information, NIH, 2026-11-08.
- GALAFOLD (MIGALASTAT HYDROCHLORIDE) CAPSULE [AMICUS THERAPEUTICS US, LLC] (prescribing information, SPL version 18). Amicus Therapeutics US, via DailyMed, 2025-08-28.
- ICD-10-CM search results for "fabry" (Clinical Table Search Service). National Library of Medicine, 2026-11-08.
A reference for licensed professionals, checked against its sources on November 8, 2026. It summarizes what the cited guidance says and does not tell anyone how to diagnose or treat a specific patient. Guidelines change; the current guideline and the treating clinician's judgment govern. Trial Friend is an independent information service, not a medical provider.
The author has done professional work for companies whose products are discussed in this article. No company reviewed, paid for or had any input into it.