The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about 12 centimetres in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.
Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common, life-threatening inherited human disorders and the most common hereditary kidney disease. It is associated with large interfamilial and intrafamilial variability, which can be explained to a large extent by its genetic heterogeneity and modifier genes. It is also the most common of the inherited cystic kidney diseases — a group of disorders with related but distinct pathogenesis, characterized by the development of renal cysts and various extrarenal manifestations, which in case of ADPKD include cysts in other organs, such as the liver, seminal vesicles, pancreas, and arachnoid membrane, as well as other abnormalities, such as intracranial aneurysms and dolichoectasias, aortic root dilatation and aneurysms, mitral valve prolapse, and abdominal wall hernias. Over 50% of patients with ADPKD eventually develop end stage kidney disease and require dialysis or kidney transplantation. ADPKD is estimated to affect at least one in every 1000 individuals worldwide, making this disease the most common inherited kidney disorder with a diagnosed prevalence of 1:2000 and incidence of 1:3000-1:8000 in a global scale.
Hyperuricaemia or hyperuricemia is an abnormally high level of uric acid in the blood. In the pH conditions of body fluid, uric acid exists largely as urate, the ion form. Serum uric acid concentrations greater than 6 mg/dL for females, 7 mg/dL for men, and 5.5 mg/dL for youth are defined as hyperuricemia. The amount of urate in the body depends on the balance between the amount of purines eaten in food, the amount of urate synthesised within the body, and the amount of urate that is excreted in urine or through the gastrointestinal tract. Hyperuricemia may be the result of increased production of uric acid, decreased excretion of uric acid, or both increased production and reduced excretion.
Alport syndrome is a genetic disorder affecting around 1 in 5,000-10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affect vision, except when changes to the lens occur in later life. Blood in urine is universal. Proteinuria is a feature as kidney disease progresses.
Lesch–Nyhan syndrome (LNS) is a rare inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). This deficiency occurs due to mutations in the HPRT1 gene located on the X chromosome. LNS affects about 1 in 380,000 live births. The disorder was first recognized and clinically characterized by American medical student Michael Lesch and his mentor, pediatrician William Nyhan, at Johns Hopkins.
Acute uric acid nephropathy is a rapidly worsening (decreasing) kidney function that is caused by high levels of uric acid in the urine (hyperuricosuria).
Cystic kidney disease refers to a wide range of hereditary, developmental, and acquired conditions and with the inclusion of neoplasms with cystic changes, over 40 classifications and subtypes have been identified. Depending on the disease classification, the presentation may be at birth, or much later into adult life. Cystic disease may involve one or both kidneys and may, or may not, occur in the presence of other anomalies. A higher incidence is found in males and prevalence increases with age. Renal cysts have been reported in more than 50% of patients over the age of 50. Typically, cysts grow up to 2.88 mm annually and may cause related pain and/or hemorrhage.
Nail–patella syndrome is a genetic disorder that results in small, poorly developed nails and kneecaps, but can also affect many other areas of the body, such as the elbows, chest, and hips. The name "nail–patella" can be very misleading because the syndrome often affects many other areas of the body, including even the production of certain proteins. Those affected by NPS may have one or more affected areas of the body, and its severity varies depending on the individual. It is also referred to as iliac horn syndrome, hereditary onychoosteodysplasia, Fong disease or Turner–Kieser syndrome.
Uromodulin (UMOD), also known as Tamm–Horsfall protein (THP), is a Zona pellucida-like domain-containing glycoprotein that in humans is encoded by the UMOD gene. Uromodulin is the most abundant protein excreted in ordinary urine.
Lecithin cholesterol acyltransferase deficiency is a disorder of lipoprotein metabolism. The disease has two forms: Familial LCAT deficiency, in which there is complete LCAT deficiency, and Fish-eye disease, in which there is a partial deficiency.
Papillorenal syndrome is an autosomal dominant genetic disorder marked by underdevelopment (hypoplasia) of the kidney and colobomas of the optic nerve.
Branchio-oto-renal syndrome (BOR) is an autosomal dominant genetic disorder involving the kidneys, ears, and neck. It often has also been described as Melnick-Fraser syndrome.
Nephronophthisis is a genetic disorder of the kidneys which affects children. It is classified as a medullary cystic kidney disease. The disorder is inherited in an autosomal recessive fashion and, although rare, is the most common genetic cause of childhood kidney failure. It is a form of ciliopathy. Its incidence has been estimated to be 0.9 cases per million people in the United States, and 1 in 50,000 births in Canada.
Medullary sponge kidney is a congenital disorder of the kidneys characterized by cystic dilatation of the collecting tubules in one or both kidneys. Individuals with medullary sponge kidney are at increased risk for kidney stones and urinary tract infection (UTI). Patients with MSK typically pass twice as many stones per year as do other stone formers without MSK. While having a low morbidity rate, as many as 10% of patients with MSK have an increased risk of morbidity associated with frequent stones and UTIs. While many patients report increased chronic kidney pain, the source of the pain, when a UTI or blockage is not present, is unclear at this time. Renal colic is present in 55% of patients. Women with MSK experience more stones, UTIs, and complications than men. MSK was previously believed not to be hereditary but there is more evidence coming forth that may indicate otherwise.
Polycystic kidney disease is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These cysts may begin to develop in utero, in infancy, in childhood, or in adulthood. Cysts are non-functioning tubules filled with fluid pumped into them, which range in size from microscopic to enormous, crushing adjacent normal tubules and eventually rendering them non-functional as well.
Autosomal recessive polycystic kidney disease (ARPKD) is the recessive form of polycystic kidney disease. It is associated with a group of congenital fibrocystic syndromes. Mutations in the PKHD1 cause ARPKD.
Megalencephalic leukoencephalopathy with subcortical cysts is a form of hereditary CNS demyelinating disease. It belongs to a group of disorders called leukodystrophies. It is characterized by early-onset enlargement of the head (macrocephaly) as well as delayed-onset neurological deterioration to include spasticity, epilepsy, and lack of muscular coordination. MLC does not appear to be a disease that is fatal at birth or early in life despite its symptoms, although the number of patients throughout history known to have the disease is fairly limited.
Autosomal dominant porencephaly type I is a rare type of porencephaly that causes cysts to grow on the brain and damage to small blood vessels, which can lead to cognitive impairment, migraines, seizures, and hemiplegia or hemiparesis.
Polycystic kidney disease 3 (autosomal dominant) is a protein that in humans is encoded by the PKD3 gene.
WNT4 deficiency is a rare genetic disorder that affects females and it results in the underdevelopment and sometimes absence of the uterus and vagina. WNT4 deficiency is caused by mutations of the WNT4 gene. Abnormally high androgen levels are found in the blood and can initiate and promote the development of male sex characteristics. This is seen as male pattern of hair growth on the chest and face. Those with this genetic defect develop breasts but do not have their period. Mayer–Rokitansky–Küster–Hauser syndrome is a related but distinct syndrome. Some women who have an initial diagnosis of MRKH have later been found to have WNT4 deficiency. Most women with MRKH syndrome do not have genetic mutations of the WNT4 gene. The failure to begin the menstrual cycle may be the initial clinical sign of WNT4 deficiency. WNT4 deficiency can cause significant psychological challenges and counseling is recommended.
