What's Alport syndrome?
Alport syndrome is a hereditary disorder of type IV collagen, caused by pathogenic variants in COL4A3, COL4A4, or COL4A5. These genes build the alpha-3/alpha-4/alpha-5 network of the glomerular basement membrane (and of structures in the ear and eye), so defects progressively damage the kidney filter. It affects the kidney, ear, and eye. Inheritance varies by gene: COL4A5 causes the X-linked form (the classic and most common, most severe in males); COL4A3 and COL4A4 cause autosomal recessive and autosomal dominant forms. This entry confirms COL4A5 as the principal driver and leaves COL4A3 and COL4A4 as unconfirmed scaffold.
| Also indexed as | ORPHA:63, MONDO:0018965 |
|---|---|
| Features mapped | 12 |
| Treatments mapped | 4 |
| Published sources | 14 |
| Last reviewed | 2026-08-04 |
Signs and symptoms
Anterior lenticonus
Anterior lenticonus, a cone-shaped bulging of the front of the lens, is the most distinctive eye finding of Alport syndrome and is far more common in affected men.
Myopia
On ocular examination, progressive myopia, anterior lenticonus, and temporal retinal thinning can be indicative of an Alport syndrome diagnosis.
Proteinuria
Over time, protein leaks into the urine (proteinuria). Rising proteinuria signals progression and is a key target of treatment.
Microscopic hematuria
Persistent microscopic hematuria (small amounts of blood in the urine, seen on testing) is usually the earliest and most consistent kidney sign of Alport syndrome.
Stage 5 chronic kidney disease
Without effective treatment the kidney disease progresses through renal impairment to kidney failure (end-stage kidney disease), which may require dialysis or a transplant. The pace varies by gene and sex.
Thickened glomerular basement membrane
In Alport syndrome the glomerular basement membrane, the kidney's filtering layer, can become abnormally thickened in places, alongside areas of thinning and a layered, split appearance. These changes are seen on a kidney biopsy under electron microscopy.
Nephritis
Alport syndrome is an inherited disorder in which faulty genes cause the kidneys to become inflamed, as well as hearing loss and eye problems.
Glomerular basement membrane lamellation
On a kidney biopsy viewed under electron microscopy, the glomerular basement membrane (the kidney's filtering layer) shows a split, layered appearance called lamellation, along with stretches that are alternately thickened and thinned. This pattern is a characteristic kidney finding of Alport syndrome.
Renal insufficiency
The kidney disease of Alport syndrome often follows a sequence over years: it begins with blood in the urine, then protein in the urine, and then a decline in how well the kidneys work (renal impairment) that can advance toward kidney failure.
Sensorineural hearing impairment
Sensorineural hearing loss, typically high-frequency, is a characteristic non-kidney feature, more common and earlier in the X-linked form.
Retinal flecks
A dot-and-fleck retinopathy, scattered specks in the retina, is another characteristic eye finding. It usually does not affect vision but helps confirm the diagnosis.
Thin glomerular basement membrane
Mutations in certain collagen genes (COL4A3, COL4A4, or COL4A5) cause the kidney's filtering membrane to become abnormally thin, leading to thin glomerular basement membrane disease or Alport-related kidney problems.
How it is diagnosed
Alport syndrome
Diagnosed using: urinalysis.
“Diagnosis relies on urinalysis, histologic examination, and genetic testing with advancements in next-generation sequencing aiding identification.”
Alport syndrome
Diagnosed using: kidney biopsy with electron microscopy.
“Kidney biopsy was done in which electron microscopy showed segmental podocyte foot process effacement. The glomerular basement membrane shows lamellation and alternate thickening and thinning.”
Treatment and management
What the research describes, not a recommendation. Treatment decisions belong with your clinician.
This covers treatments that appear in the published research mapped here. Investigational and experimental therapies are not included, so their absence is a boundary of this map, not a sign they do not exist.
ACE inhibitor
Angiotensin-converting enzyme (ACE) inhibitors are the standard of care. They lower protein in the urine and slow the decline in kidney function, delaying kidney failure. They are started early, often at the onset of proteinuria or even albuminuria.
Used to help with: Alport syndrome.
“The standard of care for patients with Alport syndrome (AS) is angiotensin-converting enzyme (ACE) inhibitors.”
SGLT2 inhibitor
SGLT2 inhibitors are added when needed to give further kidney protection on top of ACE inhibition, reflecting their broader role in slowing chronic kidney disease.
Used to help with: Alport syndrome.
“ACE inhibitors and, if necessary, SGLT2…”
kidney transplantation
When the kidneys fail, kidney transplantation provides excellent long-term outcomes. The transplanted kidney does not carry the collagen defect, though donor selection and post-transplant monitoring need care.
Used to help with: Alport syndrome.
“Kidney transplantation provides excellent long-term…”
renin-angiotensin-aldosterone system (RAAS) blockade
Blocking the renin-angiotensin-aldosterone system (RAAS), the hormone pathway that drives kidney damage, is a mainstay of treatment in Alport syndrome. By lowering protein in the urine it delays the onset of kidney failure. This is the broader drug class that includes ACE inhibitors and angiotensin receptor blockers.
Used to help with: Alport syndrome.
“Renin-angiotensin-aldosterone system blockade is proven to delay the onset of renal failure by reducing proteinuria.”
How to read the evidence labels
Where this comes from
This guide is built from 14 published source(s). Every claim above links back to one of them. Click any source ID to read the original on PubMed.
Take it further
Printed, source-linked documents built from this condition's graph — ready to bring to an appointment or attach to a coverage request. Every claim carries its published source, the same as this guide.