This is a study of a group of 23 patients from 16 families with a shared family tree, developing chronic renal insufficiency (CRI). Out of the 23 patients, 18 were female and five male with an average renal death age of 18.4 years old, showing fevo clinical manifestations. The main reason for consultation was the significant level of anemia. 17 patients had normal arterial tension, 1 patient manifested severe artery hypertension (AHT), 3 manifested mild AHT, and 2 manifested slight AHT. All the patients entered the final stage of CRI with a low level of hemoglobin overaging 6.5 g%. The urinalysis revealed an average SG of 1,010, without proteinuria or with slight proteinuria, lower than 500 mg in 24 hours. Three patients had microhematuria and the remainder had normal urinary sediment. A renal ultrasound in 18 cases revealed a bilateral reduction in the kidney size, loss of the cortcomedullar relation, an increase in the echogenety of the renal parenchyma, scattered in all cases, and the presence of corticomedullar cysts in 5 cases. The histopathological study performed in 8 cases revealed some findings which were compatible with chronic interstitial nephritis with corticomedullar cysts. The findings resemble those described in the literature in cases of familial juvenile nephronophthisis (FJN). An important aspect to be pointed out is the presence of an interstitial infiltrate with mononuclear cells, an even more significant feature than any previously reported. We can conclude that the members of these familial groups are carriers of FJN of recessive autosomic transmission, which, in view of some differences in the clinical presentation, age of onset of, CRI some biochemical and morphological findings, and the absence of genetic alterations as described in type 1 FJN, is a variant of this disease.