- Thin basement membrane disease
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MedlinePlus = 003524
eMedicineSubj = med
eMedicineTopic = 149
DiseasesDB = 5363Thin basement membrane disease (TBMD, also known as "benign familial hematuria" and "thin basement membrane nephropathy") is, along with
IgA nephropathy , the most common cause of asymptomatichematuria . The only abnormal finding in this disease is a thinning of thebasement membrane of the glomeruli in the kidneys. Its importance lies in the fact that it has a benignprognosis , with patients maintaining a normalkidney function throughout their lives.Signs and symptoms
Most patients with thin basement membrane disease are incidentally discovered to have
microscopic hematuria onurinalysis . Theblood pressure ,kidney function and the urinary protein excretion are usually normal. Mildproteinuria (less than 1.5 g/day) andhypertension are seen in a small minority of patients. Frankhematuria and loin pain should prompt a search for another cause, such askidney stone s orloin pain-hematuria syndrome . Also, there are no systemic manifestations, so presence ofhearing impairment orvisual impairment should prompt a search forhereditary nephritis such asAlport syndrome .Diagnosis
Thin basement membrane disease has to be differentiated from the other two common causes of isolated glomerular
hematuria ,IgA nephropathy andAlport syndrome . The history and presentation are helpful in this regard:
*There is usually a family history ofkidney failure , which may be associated withhearing impairment inAlport syndrome . Also, more males tend to be affected since it is more oftenX-linked .
*InIgA nephropathy , episodes of frankhematuria are more common, and a family history is rare.A kidney biopsy is the only way to diagnose thin basement membrane disease. It reveals thinning of the
glomerular basement membrane from the normal 300 to 400 nanometers (nm) to 150 to 250 nm. However, a biopsy is rarely done in cases where the patient has isolatedmicroscopic hematuria , normalkidney function and noproteinuria . The prognosis is excellent in this setting unless the clinical manifestations progress, as occurs in all males and some females withAlport syndrome and many patients withIgA nephropathy .Genetics
The molecular basis for thin basement membrane disease has yet to be elucidated fully; however, defects in the gene encoding the a4 chain of type IV collagen have been reported in some families.
Some individuals with TBMD are thought to be carries for genes that cause
Alport syndrome .ref|BuzzaTreatment
Most patients with thin basement membrane disease need just reassurance.
Angiotensin converting enzyme inhibitor s have been suggested to reduce the episodes ofhematuria , though controlled studies are lacking. Treating co-existinghypercalciuria andhyperuricosuria will also be helpful in reducinghematuria .The molecular basis for thin basement membrane disease has yet to be elucidated fully; however, defects in the gene encoding the a4 chain of type IV collagen have been reported in some families.Prognosis
Overall, most people with thin basement membrane disease have an excellent
prognosis . Some reports, however, suggest that a minority might develophypertension .ref|Nieuwhof The high incidence of thin basement disease also means that it may be co-existing with other kidney diseases, such asdiabetic nephropathy , which may have a not-so-benign prognosis.References
#Buzza M, Wang Y, Dagher H, Babon J, Cotton R, Powell H, Dowling J, Savige J. COL4A4 mutation in thin basement membrane disease previously described in Alport syndrome. Kidney International (2001) 60, 480–483. PMID 11473630
#Nieuwhof, CM, de Heer, F, de Leeuw, P, van Breda Vriesman, PJ. Thin GBM nephropathy. Premature glomerular obsolescence is associated with hypertension and late onset renal failure. Kidney Int 1997;51:1596. PMID 9150478
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