C3 glomerulopathy (C3G) is a complex ultra-rare complement-mediated renal disease caused by uncontrolled activation of the complement alternative pathway (AP) in the fluid phase (as opposed to cell surface) that is rarely inherited in a simple mendelian fashion. C3G affects individuals of all ages, with a median age at diagnosis of 23 years. Individuals with C3G typically present with hematuria, proteinuria, hematuria and proteinuria, acute nephritic syndrome or nephrotic syndrome, and low levels of the complement component C3. Spontaneous remission of C3G is uncommon, and about half of affected individuals develop end-stage renal disease (ESRD) within ten years of diagnosis, occasionally developing the late comorbidity of impaired visual acuity.

Any nephrotic syndrome in which the cause of the disease is a mutation in the EMP2 gene.

Any autoimmune disease, multisystem, infantile-onset in which the cause of the disease is a mutation in the ZAP70 gene.

Sphingosine phosphate lyase insufficiency syndrome (SPLIS) is characterized by varying combinations of steroid-resistant nephrotic syndrome (ranging from nonimmune fetal hydrops to adolescent onset), primary adrenal insufficiency (with or without mineralocorticoid deficiency), testicular insufficiency, hypothyroidism, ichthyosis, lymphopenia/immunodeficiency, and neurologic abnormalities that can include developmental delay, regression / progressive neurologic involvement, cranial nerve deficits, and peripheral motor and sensory neuropathy.

Nephrotic syndrome type 21 (NPHS21) is an autosomal recessive renal disorder characterized by onset of kidney dysfunction in the first year of life. Laboratory studies show proteinuria and renal biopsy shows diffuse mesangial sclerosis. The disorder is rapidly progressive and ultimately results in end-stage renal disease. Some patients with variable extrarenal manifestations, such as microcephaly or impaired intellectual development, have been reported, but it is not clear whether these features are consistently part of the phenotype (summary by Rao et al., 2017). (Rao et al. (2017) designated the disorder NPHS25.) For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome, see NPHS1 (256300).

Nephrotic syndrome type 22 (NPHS22) is an autosomal recessive renal disease characterized by onset of progressive kidney dysfunction in infancy. Affected individuals usually present with edema associated with hypoproteinemia, proteinuria, and microscopic hematuria. Renal biopsy shows effacement of the podocyte foot processes, glomerulosclerosis, and thickening of the glomerular basement membrane. The disease is steroid-resistant and progressive, resulting in end-stage renal disease usually necessitating kidney transplant (Majmundar et al., 2021). For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome, see NPHS1 (256300).

Nephrotic syndrome type 23 (NPHS23) is an autosomal recessive renal disorder characterized by the onset of proteinuria in the first or second decade of life. The outcome is variable: some patients have normal renal function after many years, whereas others may progress to chronic kidney disease. Renal biopsy shows mesangial hypercellularity, consistent with minimal change disease, focal segmental glomerulosclerosis, and effacement of podocyte foot processes (summary by Solanki et al., 2019). For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome and FSGS, see NPHS1 (256300).

Nephrotic syndrome type 24 (NPHS24) is an autosomal recessive renal disorder characterized by onset of proteinuria and hypoalbuminemia in early childhood, although onset in the second decade has been reported. Additional features include edema and hyperlipidemia. The disorder is slowly progressive, and most patients eventually develop end-stage renal disease. Renal biopsy shows focal segmental glomerulosclerosis (FSGS) (summary by Schneider et al., 2020). For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome, see NPHS1 (256300).

Galloway-Mowat syndrome-10 (GAMOS10) is a severe autosomal recessive disorder characterized by onset of symptoms soon after birth. Affected individuals have progressive renal dysfunction with proteinuria associated with diffuse mesangial sclerosis (DMS) on renal biopsy. Other features include global developmental delay, microcephaly, hypothyroidism, arachnodactyly, and dysmorphic facial features. Some patients may have seizures or abnormalities on brain imaging. All reported patients have died in infancy (summary by Arrondel et al., 2019 and Schmidt et al., 2021). For a general phenotypic description and a discussion of genetic heterogeneity of GAMOS, see GAMOS1 (251300).