October 2009, Volume 59, Issue 10

Letter to the Editor

The prevalence of IgA nephropathy in Pakistan: only a tip of the iceberg

Madam, IgA nephropathy (IgAN) is the most common glomerulopathy worldwide.1 It was first described by Berger and Hingalis in 1968 and is defined by the predominant or co-dominant IgA containing immune complex deposits in the kidney. As such, its diagnosis was based on and continues to be so, the histopathologic and immunohistochemical (IHC) evaluation of renal biopsy.1,2 Its reported incidence and prevalence has wide variability in different parts of the world. High rates of 20 to 50 percent have been reported in biopsy studies from Western Europe, Asia and Australia. On the other hand, very low rates have been reported from US at 2 to 10 percent, with the exception of a 38 percent incidence in the Navajo Indians in New Mexico.1 There are few studies on the prevalence of this disease in Pakistan.2-8 Earlier renal biopsy studies were based on light microscopic (LM) studies only and obviously missed this diagnosis. More recently, a few centers have started performing IHC examination on renal biopsies and cases of IgAN have begun to be reported.2-8 The first study to report on IgAN in Pakistan was published in 1988, in which 50 cases of renal biopsies were studied by immunoperoxidase method.2 IgA was demonstrated to be present by this technique in 1 case (2%). Subsequently, the same authors reported a series of 102 renal biopsies, in which IgAN was observed in 5.9% of the biopsies.3 Soon thereafter, a report followed from the northern part of the country, in which IgAN was found in 7.9% of 238 cases of glomerulopathies.4 More recently, a prevalence of 12.65% and 20.83% have been reported from different centers in two different provinces.5,6 We have reported IgAN at a rate of 2.5% and 1.1% in adults and children respectively, presenting with nephrotic syndrome.7,8 It is worth mentioning here the clinical presentation of IgAN reported in all above cited studies from Pakistan is very rare. The most common presentation of this glomerulopathy is with asymptomatic micro or macrohaematuria, which is seldom an indication of renal biopsy in centers in Pakistan. The highest rates of this glomerular disease have been reported in regions where there is mass screening of urinanalysis in populations.1 The apparent variable rates, thus most probably reflect differences in biopsy policies rather than true differences in the prevalence of this disease.1 Although, a few studies have also suggested genetic predisposition to this disorder in certain populations. It must be emphasized that the original connotation of this disease as "benign recurrent haematuria" has proved wrong in long term studies. It progresses to end stage renal disease in upto 30% of cases at 10 years. It is therefore imperative that population based surveys on the prevalence and incidence are conducted on this entity in Pakistan, so that the true face of this disease is exposed. 
Muhammed Mubarak
Histopathology Department, Sindh Institute of Urology and
Transplantation, Karachi, Pakistan.

References

1. Julian BA, Waldo FB, Rifai A, Mestecki J. IgA nephropathy, the most common glomerulonephritis worldwide. A neglected disease in the United States? Am J Med 1988; 84: 129-32.
2.Khan TN, Jafarey NA, Naqvi AJ, et al. Application of immunoperoxidase (PAP) technique for demonstration of deposited immunoglobulin in renal biopsies. J Pak Med Assoc 1988; 38: 66-9.
3.Khan TN, Sinniah R, Naqvi SA, Lal M, Osmani M. IgA nephropathy in Pakistan. J Pak Med Assoc 1990; 40: 31-6.
4.Lakhnana NK, Ahmed I, Khan SJ. IgA nephropathy in northern Pakistan. J Pak Inst Med Sci 1994; 6: 356-62.
5.Muzaffar S, Azad NS, Kayani N, Pervaiz S, Ahmed A, Hassan SH. The frequency of IgA nephropathy at a single center in Pakistan. J Pak Med Assoc 2003; 53: 301-5.
6.Noor M, Jamal SM, Mohammad W, Shah D. IgA nephropathy in North West Frontier Province of Pakistan. Gomal J Med Sci 2007; 5: 62-4.
7.Kazi JI, Mubarak M, Ahmed E, Akhter F, Naqvi SAA, Rizvi SAH. Spectrum of glomerulonephritides in adults with nephrotic syndrome in Pakistan. Clin Exp Nephrol 2009; 13: 38-43.
8.Mubarak M, Lanewala A, Kazi JI, et al. Histopathological spectrum of childhood nephrotic syndrome in Pakistan. Clin Exp Nephrol (in press).
 

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