Summary about Disease
Benign familial hematuria (BFH), also known as thin basement membrane nephropathy (TBMN), is a generally harmless inherited kidney condition characterized by persistent or recurrent microscopic hematuria (blood in the urine). It is caused by a thin glomerular basement membrane (GBM) in the kidneys. Most individuals with BFH have no other symptoms or complications and have a normal life expectancy.
Symptoms
Microscopic hematuria (blood in the urine only detectable under a microscope).
Rarely, visible hematuria (red or pink urine).
Most people have no other symptoms.
Causes
BFH is typically caused by a genetic mutation affecting the genes that code for type IV collagen, a major component of the glomerular basement membrane (GBM).
Mutations in COL4A3 or *COL4A4* are the most common causes.
It is usually inherited in an autosomal dominant pattern, meaning only one copy of the mutated gene is needed to cause the condition.
Medicine Used
There is no specific medication to cure BFH.
Treatment is generally not required as the condition is benign.
In rare cases, if there is significant proteinuria (protein in the urine) or hypertension (high blood pressure), medications like ACE inhibitors or ARBs may be considered.
Is Communicable
No, BFH is not communicable. It is a genetic condition and cannot be spread from person to person.
Precautions
Individuals with BFH should maintain a healthy lifestyle, including a balanced diet, regular exercise, and avoidance of smoking.
Regular monitoring of blood pressure and kidney function is recommended.
Genetic counseling may be considered for family planning.
How long does an outbreak last?
BFH is not an "outbreak" type of condition. The microscopic hematuria is persistent or recurrent, meaning it can be present at any time. The presence of hematuria may fluctuate, but it is generally considered a chronic condition.
How is it diagnosed?
Urinalysis: Detects microscopic hematuria.
Family history: Assessment of hematuria or kidney disease in family members.
Kidney biopsy: May be performed to examine the glomerular basement membrane thickness under a microscope (demonstrates a thin GBM). However, it's not always necessary for diagnosis, especially with a strong family history.
Genetic testing: Can confirm mutations in COL4A3 or *COL4A4*.
Timeline of Symptoms
Microscopic hematuria is usually detected incidentally during routine urine testing or investigations for other reasons.
It may be present from a young age (childhood) or discovered later in life.
The hematuria can be persistent or intermittent, with periods of increased and decreased blood in the urine.
Important Considerations
BFH is usually a benign condition with an excellent prognosis.
It's crucial to differentiate it from other causes of hematuria, such as glomerulonephritis or kidney stones.
Although rare, some individuals with COL4A3 or *COL4A4* mutations may be at increased risk for developing Alport syndrome, a more severe kidney disease, particularly if they inherit two mutated copies of the gene or have other risk factors.
Monitoring for proteinuria and hypertension is important, although these are uncommon in BFH.