Minimal change disease (MCD) is the major cause of idiopathic nephrotic syndrome (NS) in children, accounting for 70% to 90% of cases in children over 1 year of age.[1]Vivarelli M, Massella L, Ruggiero B, et al. Minimal change disease. Clin J Am Soc Nephrol. 2017 Feb 7;12(2):332-45.
https://cjasn.asnjournals.org/content/12/2/332.long
http://www.ncbi.nlm.nih.gov/pubmed/27940460?tool=bestpractice.com
In adults with NS, MCD is the cause in around 15% of patients.[1]Vivarelli M, Massella L, Ruggiero B, et al. Minimal change disease. Clin J Am Soc Nephrol. 2017 Feb 7;12(2):332-45.
https://cjasn.asnjournals.org/content/12/2/332.long
http://www.ncbi.nlm.nih.gov/pubmed/27940460?tool=bestpractice.com
In a study of kidney biopsies among 1633 adults with NS, the incidence of MCD was 19.5%.[6]Su S, Yu J, Wang Y, et al. Clinicopathologic correlations of renal biopsy findings from northeast China: A 10-year retrospective study. Medicine (Baltimore). 2019 Jun;98(23):e15880.
https://journals.lww.com/md-journal/Fulltext/2019/06070/Clinicopathologic_correlations_of_renal_biopsy.29.aspx
http://www.ncbi.nlm.nih.gov/pubmed/31169695?tool=bestpractice.com
The overall incidence of idiopathic NS is estimated at 2.92 new cases per 100,000 children per year.[7]Veltkamp F, Rensma LR, Bouts AHM, et al. Incidence and relapse of idiopathic nephrotic syndrome: meta-analysis. Pediatrics. 2021 Jul;148(1):e2020029249.
https://publications.aap.org/pediatrics/article/148/1/e2020029249/179943/Incidence-and-Relapse-of-Idiopathic-Nephrotic
http://www.ncbi.nlm.nih.gov/pubmed/34193618?tool=bestpractice.com
The incidence is higher in Southeast Asia and East Asia compared with Europe, North America, and Oceania.[7]Veltkamp F, Rensma LR, Bouts AHM, et al. Incidence and relapse of idiopathic nephrotic syndrome: meta-analysis. Pediatrics. 2021 Jul;148(1):e2020029249.
https://publications.aap.org/pediatrics/article/148/1/e2020029249/179943/Incidence-and-Relapse-of-Idiopathic-Nephrotic
http://www.ncbi.nlm.nih.gov/pubmed/34193618?tool=bestpractice.com
The age at initial presentation of NS has an impact on the MCD distribution frequency.[8]Ranganathan S. Pathology of podocytopathies causing nephrotic syndrome in children. Front Pediatr. 2016;4:32.
https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2016.00032/full
http://www.ncbi.nlm.nih.gov/pubmed/27066465?tool=bestpractice.com
For children presenting with NS before the age of 1 year, congenital (birth to 3 months) and infantile (3-12 months) genetic disorders, as well as infections, are usually the causes. In children beyond infancy and ages <6 years, MCD is the predominant finding.[8]Ranganathan S. Pathology of podocytopathies causing nephrotic syndrome in children. Front Pediatr. 2016;4:32.
https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2016.00032/full
http://www.ncbi.nlm.nih.gov/pubmed/27066465?tool=bestpractice.com
In contrast, only 20% to 30% of adolescent patients with NS have MCD.[9]Baqi N, Singh A, Balachandra S, et al. The paucity of minimal change disease in adolescents with primary nephrotic syndrome. Pediatr Nephrol. 1998;12:105-107.
http://www.ncbi.nlm.nih.gov/pubmed/9543365?tool=bestpractice.com
Reliable epidemiologic data with a pathologic diagnosis are lacking as many patients, particularly children and individuals in low-resource settings, do not undergo biopsy.[8]Ranganathan S. Pathology of podocytopathies causing nephrotic syndrome in children. Front Pediatr. 2016;4:32.
https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2016.00032/full
http://www.ncbi.nlm.nih.gov/pubmed/27066465?tool=bestpractice.com
The sex ratio of boys to girls approximates 2:1 during childhood, but this difference disappears in adolescence.[1]Vivarelli M, Massella L, Ruggiero B, et al. Minimal change disease. Clin J Am Soc Nephrol. 2017 Feb 7;12(2):332-45.
https://cjasn.asnjournals.org/content/12/2/332.long
http://www.ncbi.nlm.nih.gov/pubmed/27940460?tool=bestpractice.com