Task: Question Answering
Input (English): Question: 30-year-old man without a history of interest. He came to the clinic because of the presence of small erythematous-violaceous lesions that appear elevated on palpation, in the pretibial region. The analytical study shows a blood count and coagulation study without alterations and in the biochemistry, creatinine and ions are also within the range of normality. The study of urinary sediment demonstrates hematuria, for which the patient had already been studied on other occasions, without obtaining a definitive diagnosis. Regarding the entity that you suspect in this case is FALSE that: 
 Options:  <1> In 20% to 50% of cases there is an elevation of the serum IgA concentration. <2> In the renal biopsy the mesangial deposits of IgA are characteristic. <3> The existence of proteinuria in the nephrotic range is frequent. <4> It is considered a benign entity since less than 1/3 of the patients progress to renal failure. <5> Skin biopsy allows the diagnosis to be established in up to half of the cases.
Output (English): 3