Nephrosis is any of various forms of kidney disease (nephropathy). In an old and broad sense of the term, it is any nephropathy, but in current usage the term is usually restricted to a narrower sense of nephropathy without inflammation or neoplasia, in which sense it is distinguished from nephritis, which involves inflammation. It is also defined as any purely degenerative disease of the renal tubules. Nephrosis is characterized by a set of signs called the nephrotic syndrome. Nephrosis can be a primary disorder or can be secondary to another disorder. Nephrotic complications of another disorder can coexist with nephritic complications. In other words, nephrosis and nephritis can be pathophysiologically contradistinguished, but that does not mean that they cannot occur simultaneously.

Types of nephrosis include amyloid nephrosis and osmotic nephrosis.

Osmotic nephrosis refers to structural changes that occur at the cellular level in the human kidney. Cells, primarily of the straight proximal tubule, swell due to the formation of large vacuoles in the cytoplasm. These vacuoles occur in the presence of large amounts of certain solutes circulating in the tubules. However, despite the condition's name, the solutes do not cause change through osmotic forces but through pinocytosis. Once inside the cytoplasm, pinocytic vacuoles combine with each other and with lysosomes to form large vacuoles that appear transparent under microscopic examination.

There may be no symptomatic presentation with this condition, or it may confused with other nephrotic conditions such as Tubular calcineurin-inhibitor toxicity. Affected cells of the proximal tubule may be passed in the urine, but a kidney biopsy is the only sure way to make a diagnosis.

Responsible exogenous solutes include sucrose-containing IVIg, mannitol, dextran, contrast dye, and hydroxyethyl starch. Prevention includes standard preventions for iatrogenic kidney damage. Osmotic nephrosis is usually reversible but can lead to chronic renal failure.

Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine (bilirubinuria), retrograde ejaculation, pneumaturia (air bubbles in the urine) due to a fistula, or drugs such as pyridium.

There are three main mechanisms to cause proteinuria:

- Due to disease in the glomerulus

- Because of increased quantity of proteins in serum (overflow proteinuria)

- Due to low reabsorption at proximal tubule (Fanconi syndrome)

Proteinuria can also be caused by certain biological agents, such as bevacizumab (Avastin) used in cancer treatment. Excessive fluid intake (drinking in excess of 4 litres of water per day) is another cause.

Also leptin administration to normotensive Sprague Dawley rats during pregnancy significantly increases urinary protein excretion.

Proteinuria may be a sign of renal (kidney) damage. Since serum proteins are readily reabsorbed from urine, the presence of excess protein indicates either an insufficiency of absorption or impaired filtration. People with diabetes may have damaged nephrons and develop proteinuria. The most common cause of proteinuria is diabetes, and in any person with proteinuria and diabetes, the cause of the underlying proteinuria should be separated into two categories: diabetic proteinuria versus the field.

With severe proteinuria, general hypoproteinemia can develop which results in

diminished oncotic pressure. Symptoms of diminished oncotic pressure may include ascites, edema and hydrothorax.

Kidney disease is a non-communicable disease, having serious consequences if it cannot be controlled effectively. Generally, the process of kidney disease development is from light to serious. Some kidney diseases can cause renal failure.

The clinical signs of minimal change disease are proteinuria (abnormal excretion of proteins, mainly albumin, into the urine), oedema (swelling of soft tissues as a consequence of water retention), and hypoalbuminaemia (low serum albumin). These signs are referred to collectively as nephrotic syndrome. Minimal change disease is unique among the causes of nephrotic syndrome as it lacks evidence of pathology in light microscopy, hence the name.

When albumin is excreted in the urine, its serum (blood) concentration decreases. Consequently, the intravascular oncotic pressure reduces relative to the interstitial tissue. The subsequent movement of fluid from the vascular compartment to the interstitial compartment manifests as the soft tissue swelling referred to as oedema. This fluid collects most commonly in the feet and legs, in response to gravity, particularly in those with poorly functioning valves. In severe cases, fluid can shift into the peritoneal cavity (abdomen) and cause ascites. As a result of the excess fluid, individuals with minimal change disease often gain weight, as they are excreting less water in the urine, and experience fatigue. Additionally, the protein in the urine causes it to become frothy.

Kidney disease, also known as nephropathy or renal disease, is damage to or disease of a kidney. Nephritis is inflammatory kidney disease. Nephrosis is noninflammatory kidney disease. Kidney disease usually causes kidney failure to some degree, with the amount depending on the type of disease. In precise usage, "disease" denotes the structural and causal disease entity whereas "failure" denotes the impaired kidney function. In common usage these meanings overlap; for example, the terms "chronic kidney disease" and "chronic renal failure" are usually considered synonymous. Acute kidney disease has often been called acute renal failure, although nephrologists now often tend to call it acute kidney injury. About 1 in 8 Americans suffer from chronic kidney disease.

Congenital nephrotic syndrome is a very rare form of nephrotic syndrome. It occurs predominantly in families of Finnish origin and manifests shortly after birth. It is an inherited disorder. The condition is caused by a defect in the protein nephrin, which is found in the kidney.

Proteins and fats are excreted in the urine, and there is an abnormally high fat level in the blood. Swelling occurs due to kidney failure, combined with the loss of blood protein. This is because proteins in the blood normally keep fluids in the blood stream, and when protein level is low, the fluid can leak into the body tissues.

Some of the proteins lost in the urine are immune system antibodies that fight infections. The disorder commonly results in infection, malnutrition, and kidney failure.

Minimal change disease has been called by many other names in the medical literature, including minimal change nephropathy, minimal change nephrosis, minimal change nephrotic syndrome, minimal change glomerulopathy, foot process disease (referring to the foot processes of the podocytes), nil disease (referring to the lack of pathologic findings on light microscopy), nil lesions, lipid nephrosis, and lipoid nephrosis.

An examination reveals massive fluid retention and generalized swelling. Abnormal sounds are heard when listening to the heart and lungs with a stethoscope. Blood pressure may be high. The patient may have signs of malnutrition.

A urinalysis reveals large amounts of protein and the presence of fat in the urine. Total protein in the blood may be low. The disorder can be screened during pregnancy by finding elevated levels of alpha-fetoprotein on a routine sampling of amniotic fluid. Genetic tests should be used to confirm the diagnosis, if the screening test is positive.

CNF is one of the Finnish heritage diseases. By use of positional cloning strategies, Kestila et al. isolated the gene responsible for NPHS1. Mutations in Finnish patients with NPHS1 were found in this gene, which they termed nephrin. The most common Finnish mutation was a deletion of 2 nucleotides in exon 2 (602716.0001), resulting in a frameshift and a truncated protein. The predicted nephrin protein belongs to the immunoglobulin family of cell adhesion molecules and is specifically expressed in renal glomeruli. It was also observed that, in most cases, alleles typically found on CNF chromosomes of Finnish families were also found on CNF chromosomes of non-Finnish families from North America and Europe.

Frequent infections may occur over the course of the disease.

Meckel syndrome (also known as Meckel–Gruber Syndrome, Gruber Syndrome, Dysencephalia Splanchnocystica) is a rare, , ciliopathic, genetic disorder, characterized by renal cystic dysplasia, central nervous system malformations (occipital encephalocele), polydactyly (post axial), hepatic developmental defects, and pulmonary hypoplasia due to oligohydramnios.

Meckel–Gruber syndrome is named for Johann Meckel and Georg Gruber.

Dysplastic kidneys are prevalent in over 95% of all identified cases. When this occurs, microscopic cysts develop within the kidney and slowly destroy it, causing it to enlarge to 10 to 20 times its original size. The level of amniotic fluid within the womb may be significantly altered or remain normal, and a normal level of fluid should not be criteria for exclusion of diagnosis.

Occipital encephalocele is present in 60% to 80% of all cases, and post-axial polydactyly is present in 55% to 75% of the total number of identified cases. Bowing or shortening of the limbs are also common.

Finding at least two of the three phenotypic features of the classical triad, in the presence of normal karyotype, makes the diagnosis solid. Regular ultrasounds and pro-active prenatal care can usually detect symptoms early on in a pregnancy.

CCD causes persistent secretory diarrhea. In a fetus, it leads to polyhydramnios and premature birth. Immediately after birth, it leads to dehydration, hypoelectrolytemia, hyperbilirubinemia, abdominal distention, and failure to thrive.

Glomerulonephrosis is a non-inflammatory disease of the kidney (nephrosis) presenting primarily in the glomerulus (a glomerulopathy).

It can be contrasted to glomerulonephritis, which implies inflammation.

It can be caused by diethylnitrosamine.

Infants with LPI are usually symptom-free when breastfed because of the low protein concentration in human milk, but develop vomiting and diarrhea after weaning. The patients show failure to thrive, poor appetite, growth retardation, enlarged liver and spleen, prominent osteoporosis and osteopenia, delayed bone age and spontaneous protein aversion. Forced feeding of protein may lead to convulsions and coma. Mental development is normal if prolonged episode of hyperammonemia can be avoided. Some patients develop severe pulmonary and renal complications. High levels of plasma glutamine and glycine are observed.

CCD may be detectable on prenatal ultrasound. After birth, signs in affected babies typically are abdominal distension, visible peristalsis, and watery stools persistent from birth that show chloride loss of more than 90 mmol/l.

An important feature in this diarrhea that helps in the diagnosis, is that it is the only type of diarrhea that causes metabolic alkalosis rather than metabolic acidosis.

GRACILE syndrome is a very rare autosomal recessive genetic disorder, one of the Finnish heritage diseases. It is caused by mutation in BCS1L gene that occurs in at least 1 out of 47,000 live births in Finnish people.

GRACILE is an acronym for growth retardation, amino aciduria (amino acids in the urine), cholestasis, iron overload, lactic acidosis, and early death. Other names for this syndrome include Finnish lethal neonatal metabolic syndrome (FLNMS); lactic acidosis, Finnish, with hepatic hemosiderosis; and Fellman syndrome.

Lysinuric protein intolerance (LPI), also called hyperdibasic aminoaciduria type 2,cationic aminoaciduria or familial protein intolerance, is an autosomal recessive metabolic disorder affecting amino acid transport.

About 140 patients have been reported, almost half of them of Finnish origin. Individuals from Japan, Italy, Morocco and North Africa have also been reported.

Hereditary gelsolin amyloidosis is a cutaneous condition inherited in an autosomal dominant fashion.

The condition was first described in 1969, by the Finnish ophthalmologist Jouko Meretoja, and is also known as Familial amyloid neuropathy type IV, Meretoja syndrome, Hereditary amyloidosis, Finnish type.

The disorder primarily associated with eye, skin and cranial nerve symptoms. It is a form of amyloidosis, where the amyloid complexes are formed from fragments of the protein gelsolin in the plasma, due to a mutation in the GSN gene (c.654G>A or c.654G>T).

One Finnish study which followed 25 cases from 18 families found that half the infants died within 3 days of birth and the other half died before 4 months of age.

Sialuria is a condition where there is increased sialic acid in the urine.

Types include:

- Salla disease ("Finnish type sialuria")

- "French type sialuria" (), associated with "GNE"

The presentation of Ullrich congenital muscular dystrophy in an affected individual is as follows:

- Muscle weakness

- Difficulty walking

- Contractures (neck)

- Joint looseness

An individual with Mulibrey nanism has growth retardation, a short broad neck, misshapen sternum, small thorax, square shoulders, enlarged liver, and yellowish dots in the ocular fundi. Individuals with Mulibrey nanism have also been reported to have mental retardation, tumors, and infertility.

At birth, there is no sign that a child will develop symptoms of aspartylglucosaminuria. Typically, signs and symptoms become apparent between two and four years of age and become progressively worse as the individual ages. The following signs and symptoms may appear:

- Individuals are more prone to respiratory infections

- Development of scoliosis

- Seizures or difficulty with movement

- Skin and joints may become loose

- Facial features change progressively; this may include:

- Progression of developmental and mental disabilities, including:

- An intellectual peak occurs in the mid-teens and allows a plateau for the disease. Once an individual hits the age of 25-30 the decrease begins again, including:

(Children are physically uncoordinated, but remain able to play sports and do everyday activities until they reach adulthood.)

- During the first year of life inguinal and umbilical hernias are common.

- Less severe symptoms include:

- People with aspartylglucosaminuria may have lower than average height, because they tend to go through puberty earlier.

- Epilepsy may develop in adulthood.

- Finnish studies have shown that life expectancy is shorter than average.

Individuals with Salla disease may present with nystagmus in the first months of life as well as hypotonia, reduced muscle tone and strength, and cognitive impairment. The most severely impaired children do not walk or acquire language, but the typical patient learns to walk and speak and has normal life expectancy. The MRI shows arrested or delayed myelination.