a detailed description of patients with history of recurrent respiratory infections and progressive renal failure was given 1979 .
the case under discussion has various rare features like young age of the patient , associated glomerulopathy causing nephrotic syndrome and normal renal function , which is showing gradual deterioration .
normal renal function at the time of diagnosis is known and in one large series published by bhandari et al .
an 8-year - old male child presented with a history of facial puffiness and edema of one year duration .
he was diagnosed to have nephrotic syndrome and was treated by a local physician with steroids .
he did not improve , however , and was referred to this hospital for further management .
there was no history of drug ingestion including exposure to mycotoxins or other herbal medicines .
patient had stunted growth with moon facies , secondary to steroids and had clinical features of rickets .
his investigations revealed hemoglobin of 10 g / dl , blood urea 33 mg / dl and serum creatinine 0.7 mg / dl .
he was human immunodeficiency virus non - reactive and hepatitis b surface antigen and hepatitis c virus and 24 h urine protein was 3565 mg / dl .
complete urine examination showed 2 + albumin , 4 - 6 red blood cells and granular casts .
he was started on cyclophosphamide . however , there was no response even after 6 months .
biopsy showed 23 glomeruli , four of whom showed segmental sclerosis [ figure 1 ] .
segmental glomerulosclerosis ( thin arrow ) and karyomegaly in tubular cells ( thick arrow ) ( h and e , 400 ) karyomegaly in tubular epithelial cells ( h and e , 400 ) ( a ) segmental sclerosis and tubular atrophy ( periodic acid schiff , 200 ) .
( b ) tubular atrophy and interstitial inflammation ( h and e , 200 ) .
( c ) interstitial fibrosis ( masson 's trichrome , 200 ) immunohistochemical stains for bk virus and cytomegalovirus were negative .
he is under regular follow - up and his last creatinine has increased to 1.2 mg / dl .
kin is a rare disorder characterized by enlarged tubular epithelial cell nuclei and chronic interstitial nephritis .
histologically , presence of interstitial nephritis along with karyomegaly in the tubular epithelial cells is characteristic of this disorder .
karyomegalic cells have been identified in various tissues like astrocytes , schwann cells , intestinal smooth muscle and bile duct epithelium .
mcculloch et al . , reported kin in three adolescent patients treated with ifosfamide for ewings sarcoma .
a familial clustering is known and frequency of human leukocyte antigen ( hla)-a9 and hla - b35 haplotypes suggest the possibility of genetic susceptibility .
another genetic defect on chromosome 6 , linked to major histocompatibility complex locus is also suspected .
the morphological alterations in renal epithelial cells are thought to be the initial damage caused by either chemicals or viral agents , which in susceptible individuals lead to disruption of cells .
immunofluorescence and histological findings are negative in a large series presented by bhandari et al .
in contrast our case clinically presented with nephrotic syndrome and also had histological evidence of focal segmental glomerulosclerosis ( fsgs ) . as there is no positive family history or drug history and exposure to toxins ,
it is important to diagnose this entity as it is a progressive disorder leading to irreversible renal damage .
common etiological factors for both these lesions are toxins and drugs , patient on repeated questioning denied any history of drug or herbal medicine intake .
there is no history of renal disease in the family and it unlikely to be familial because the chromosomal abnormalities described are different for both .
spoendlin et al . , reported four patients who were asymptomatic initially , but later experienced progressive renal failure .
this particular case under discussion also initially presented with normal renal function and on follow - up was showing gradual deterioration .
we present a rare case of kin who initially presented with normal renal parameters ; interestingly , this patient 's clinical presentation was of nephrotic syndrome whose biopsy also revealed fsgs .
hence , we think that the patient has idiopathic fsgs with an incidental kin , which is known to occur sporadically .
 karyomegalic interstitial nephritis ( kin ) is a rare form of , progressive chronic interstitial nephritis . 
 we present a case of kin in a child , who was also found to have nephrotic syndrome because of focal segmental glomerulosclerosis on renal biopsy . to our knowledge , this is the first case of kin associated with glomerulopathy . 