The nephrotic syndrome is characterized clinically by proteinuria, hypoalbuminemia, hyperlipidemia, and edema. Kidney biopsies show nonspecific histologic changes such as minimal change, focal segmental glomerulosclerosis (FSGS), and diffuse mesangial proliferation. Approximately 20% of affected individuals have an inherited steroid-resistant form and progress to end-stage renal failure (summary by Fuchshuber et al., 1996). Nephrotic syndrome type 1 (NPHS1) is characterized by prenatal onset of massive proteinuria followed by severe steroid-resistant nephrotic syndrome apparent at birth with rapid progression to end-stage renal failure (Kestila et al., 1998). Because of confusion in the literature regarding use of the terms 'nephrotic syndrome' and 'focal segmental glomerulosclerosis' (see NOMENCLATURE section), these disorders in OMIM are classified as NPHS or FSGS according to how they were first designated in the literature. Genetic Heterogeneity of Nephrotic Syndrome and Focal Segmental Glomerulosclerosis Nephrotic syndrome and FSGS are genetically heterogeneous disorders representing a spectrum of hereditary renal diseases. See also NPHS2 (600995), caused by mutation in the podocin gene (604766); NPHS3 (610725), caused by mutation in the PLCE1 gene (608414); NPHS4 (256370), caused by mutation in the WT1 gene (607102); NPHS5 (614199), caused by mutation in the LAMB2 gene (150325); NPHS6 (614196), caused by mutation in the PTPRO gene (600579); NPHS7 (615008), caused by mutation in the DGKE gene (601440); NPHS8 (615244), caused by mutation in the ARHGDIA gene (601925); NPHS9 (615573), caused by mutation in the COQ8B gene (615567); NPHS10 (615861), caused by mutation in the EMP2 gene (602334); NPHS11 (616730), caused by mutation in the NUP107 gene (607617); NPHS12 (616892), caused by mutation in the NUP93 gene (614351); NPHS13 (616893), caused by mutation in the NUP205 gene (614352); NPHS14 (617575), caused by mutation in the SGPL1 gene (603729); NPHS15 (617609), caused by mutation in the MAGI2 gene (606382); NPHS16 (617783), caused by mutation in the KANK2 gene (614610), NPHS17 (618176), caused by mutation in the NUP85 gene (170285); NPHS18 (618177), caused by mutation in the NUP133 gene (607613); NPHS19 (618178), caused by mutation in the NUP160 gene (607614); NPHS20 (301028), caused by mutation in the TBC1D8B gene (301027); NPHS21 (618594) caused by mutation in the AVIL gene (613397); NPHS22 (619155), caused by mutation in the NOS1AP gene (605551); NPHS23 (619201), caused by mutation in the KIRREL1 gene (607428); NPHS24 (619263), caused by mutation in the DAAM2 gene (606627); and NPHS26 (620049), caused by mutation in the LAMA5 gene (601033). The symbol NPHS25 has been used as an alternative designation for NPHS21. See also FSGS1 (603278), caused by mutation in the ACTN4 gene (604638); FSGS2 (603965), caused by mutation in the TRPC6 gene (603652); FSGS3 (607832), associated with variation in the CD2AP gene (604241); FSGS4 (612551), mapped to chromosome 22q12; FSGS5 (613237), caused by mutation in the INF2 gene (610982); FSGS6 (614131), caused by mutation in the MYO1E gene (601479); FSGS7 (616002), caused by mutation in the PAX2 gene (167409); FSGS8 (616032), caused by mutation in the ANLN gene (616027); and FSGS9 (616220), caused by mutation in the CRB2 gene (609720).

X-linked recessive nephrolithiasis with renal failure (XRN) is a form of X-linked hypercalciuric nephrolithiasis, which comprises a group of disorders characterized by proximal renal tubular reabsorptive failure, hypercalciuria, nephrolithiasis, and renal insufficiency. These disorders have also been referred to as the 'Dent disease complex' (Scheinman, 1998; Gambaro et al., 2004). For a general discussion of Dent disease, see 300009.

Low molecular weight proteinuria with hypercalciuria and nephrocalcinosis is a form of X-linked hypercalciuric nephrocalcinosis, a group of disorders characterized by proximal renal tubular reabsorptive failure, hypercalciuria, nephrocalcinosis, and renal insufficiency. These disorders have also been referred to as the 'Dent disease complex' (Scheinman, 1998; Gambaro et al., 2004). For a general discussion of Dent disease, see 300009.

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

Classic Joubert syndrome (JS) is characterized by three primary findings: A distinctive cerebellar and brain stem malformation called the molar tooth sign (MTS). Hypotonia. Developmental delays. Often these findings are accompanied by episodic tachypnea or apnea and/or atypical eye movements. In general, the breathing abnormalities improve with age, truncal ataxia develops over time, and acquisition of gross motor milestones is delayed. Cognitive abilities are variable, ranging from severe intellectual disability to normal. Additional findings can include retinal dystrophy, renal disease, ocular colobomas, occipital encephalocele, hepatic fibrosis, polydactyly, oral hamartomas, and endocrine abnormalities. Both intra- and interfamilial variation are seen.

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

Any arthrogryposis-renal dysfunction-cholestasis syndrome in which the cause of the disease is a mutation in the VPS33B gene.

Autosomal dominant tubulointerstitial kidney disease – MUC1 (ADTKD-MUC1) is characterized by slowly progressive tubulointerstitial disease that leads to end-stage renal disease (ESRD) and the need for dialysis or kidney transplantation. The rate of loss of kidney function for individuals is variable within and between families, with a median age of onset of end-stage renal disease (ESRD) of 46 years (range: ages 20-70 years). There are no other systemic manifestations.

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

The two clinical presentations observed in autosomal dominant tubulointerstitial kidney disease – REN (ADTKD-REN) correlate with the renin protein domains affected by the causative REN variants. Childhood/adolescent onset, the more common presentation (caused by REN variants encoding the signal peptide or prosegment domains), is characterized by decreased estimated glomerular filtration rate, acidosis, hyperkalemia, and anemia early in life, followed by slowly progressive chronic kidney disease (CKD) and gout. Adult onset, the less common presentation (caused by REN variants encoding the mature renin peptide), is characterized by gout or mild slowly progressive CKD, beginning in the third decade. Anemia, hyperkalemia, and acidemia do not occur.

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

Focal segmental glomerulosclerosis-6 is an autosomal recessive childhood-onset kidney disorder manifest clinically by the nephrotic syndrome, which is characterized by proteinuria, hematuria, hypoalbuminemia, and progressive renal failure. It is a disease of the glomerular podocyte (summary by Mele et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of focal segmental glomerulosclerosis and nephrotic syndrome, see FSGS1 (603278).

The nephronophthisis (NPH) phenotype is characterized by reduced renal concentrating ability, chronic tubulointerstitial nephritis, cystic renal disease, and progression to end-stage renal disease (ESRD) before age 30 years. Three age-based clinical subtypes are recognized: infantile, juvenile, and adolescent/adult. Infantile NPH can present in utero with oligohydramnios sequence (limb contractures, pulmonary hypoplasia, and facial dysmorphisms) or postnatally with renal manifestations that progress to ESRD before age 3 years. Juvenile NPH, the most prevalent subtype, typically presents with polydipsia and polyuria, growth retardation, chronic iron-resistant anemia, or other findings related to chronic kidney disease (CKD). Hypertension is typically absent due to salt wasting. ESRD develops at a median age of 13 years. Ultrasound findings are increased echogenicity, reduced corticomedullary differentiation, and renal cysts (in 50% of affected individuals). Histologic findings include tubulointerstitial fibrosis, thickened and disrupted tubular basement membrane, sporadic corticomedullary cysts, and normal or reduced kidney size. Adolescent/adult NPH is clinically similar to juvenile NPH, but ESRD develops at a median age of 19 years. Within a subtype, inter- and intrafamilial variability in rate of progression to ESRD is considerable. Approximately 80%-90% of individuals with the NPH phenotype have no extrarenal features (i.e., they have isolated NPH); ~10%-20% have extrarenal manifestations that constitute a recognizable syndrome (e.g., Joubert syndrome, Bardet-Biedl syndrome, Jeune syndrome and related skeletal disorders, Meckel-Gruber syndrome, Senior-Løken syndrome, Leber congenital amaurosis, COACH syndrome, and oculomotor apraxia, Cogan type).

Nephrotic syndrome type 11 (NPHS11) is an autosomal recessive disorder of the kidney with onset in the first decade of life. The disorder is progressive and usually results in end-stage renal disease necessitating renal transplantation, although some patients may have a slightly milder phenotype (Miyake et al., 2015). For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome, see NPHS1 (256300).

MPSPS is an autosomal recessive inborn error of metabolism resulting in a multisystem disorder with features of the mucopolysaccharidosis lysosomal storage diseases (see, e.g., 607016). Patients present in infancy or early childhood with respiratory difficulties, cardiac problems, anemia, dysostosis multiplex, renal involvement, coarse facies, and delayed psychomotor development. Most patients die of cardiorespiratory failure in the first years of life (summary by Kondo et al., 2017).

Junctional epidermolysis bullosa-7 with interstitial lung disease and nephrotic syndrome (JEB7), also known as ILNEB, is an autosomal recessive multiorgan disorder that includes congenital interstitial lung disease, nephrotic syndrome, and epidermolysis bullosa. The respiratory and renal features predominate, and lung involvement accounts for the lethal course of the disease (summary by Has et al., 2012).

Autosomal dominant tubulointerstitial kidney disease – UMOD (ADTKD-UMOD) is characterized by normal urinalysis and slowly progressive chronic kidney disease (CKD), usually first noted in the teen years and progressing to end-stage renal disease (ESRD) between the third and seventh decades. Hyperuricemia is often present from an early age, and gout (resulting from reduced kidney excretion of uric acid) occurs in the teenage years in about 8% of affected individuals and develops in 55% of affected individuals over time.

Galloway-Mowat syndrome-7 (GAMOS7) is an autosomal recessive disorder characterized by developmental delay, microcephaly, and early-onset nephrotic syndrome (summary by Rosti et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of GAMOS, see GAMOS1 (251300).

Galloway-Mowat syndrome-8 (GAMOS8) is an autosomal recessive disorder characterized by impaired psychomotor development, poor overall growth with microcephaly, and early-onset progressive nephrotic syndrome associated with focal segmental glomerulosclerosis on renal biopsy. Some patients may have seizures, and some may die in childhood (summary by Fujita et al., 2018). For a general phenotypic description and a discussion of genetic heterogeneity of GAMOS, see GAMOS1 (251300).

COACH syndrome is classically defined as Cerebellar vermis hypoplasia, Oligophrenia, Ataxia, Colobomas, and Hepatic fibrosis (Verloes and Lambotte, 1989). Brain MRI demonstrates the molar tooth sign, which is a feature of Joubert syndrome. The disorder has been described as a Joubert syndrome-related disorder with liver disease (summary by Doherty et al., 2010). For a general phenotypic description and a discussion of genetic heterogeneity of COACH syndrome, see 216360.