Aagenaes syndrome | |
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Other names | Aagenæs syndrome, Cholestasis-lymphedema syndrome |
Aagenaes syndrome is inherited in an autosomal recessive manner |
Aagenaes syndrome is a syndrome characterised by congenital hypoplasia of lymph vessels, which causes lymphedema of the legs and recurrent cholestasis in infancy, and slow progress to hepatic cirrhosis and giant cell hepatitis with fibrosis of the portal tracts. [1] [2]
The genetic cause is due to point mutation (c.-98G>T) in the 5’-untranslated region of Unc-45 myosin chaperone A (UNC45A) [3] and it is autosomal recessively inherited and the gene is located to chromosome 15q1,2. The mutation leads to a loss of function of the protein, which in turn seem to lead to mislocalization of the hepatobiliary transport proteins BSEP (bile salt export pump) and MRP2 (multidrug resistance-associated protein 2) [4] .
A common feature of the condition is a generalised lymphoedema from birth or childhood caused by hypoplasia of the lymphatic vessels in origin1. Approximately one hundred people with this disease are known. [5] The condition is particularly frequent in southern Norway, where more than half the cases are reported, but it is found in patients in other parts of Europe and the United States. [6] It is named after Øystein Aagenæs, a Norwegian paediatrician. [7] It is also called cholestasis-lymphedema syndrome (CLS). [8]
The first case of cholestasis usually improves spontaneously during preschool and early school age and returns at various intervals of two to six months. [5] The severity of the disease varies in these patients, with some even experiencing complete liver failure. In these cases, liver transplantation is necessary. [5] [9] Untreated cholestasis is accompanied by jaundice, itching, malabsorption of fat and fat-soluble vitamins. This can lead to skeletal abnormalities and a higher susceptibility to bleeding. [5] In early childhood and adolescence, lymphedema most often develops in all patients' lower limbs, but the upper limbs or chest are no exception. [5] [9] Untreated lymphedema can cause chronic tissue damage. [5]
A biochemical analysis revealed a significant increase of bilirubin concentration in patients in the first months of life, with a later decrease. Around the age of 3 or 4, the value was optimized to normal limits. [10]
In patients aged 10–20 years, serum concentrations of bilirubin, bile acids and transaminases (alanine aminotransferase, aspartate aminotransferase) reached normal or almost optimal values. [10] [11]
Patients without observed liver cirrhosis compared to the control group had elevated levels of ALP (alkaline phosphatase) and GGT (gamma-glutamyl transferase). There was no significant difference in serum bile acid concentrations between patients and control group. However, test patients had lower values for total protein, CRP, albumin and creatinine. Moreover, the value for fibrinogen was higher in patients with Aagenaes syndrome. [10]
There was only a slight increase in mean cell hemoglobin (MCH) in terms of erythrocyte, leukocyte and platelet counts. Serum albumin concentrations decreased with age, but not in the control group. [10]
Although no cure for this disease has been found, improvements in the course of the disease have been significantly seen after the administration of nutritional and vitamin supplements, especially in children. It is stated that if there is no remission by about 12 to 18 months of childhood, liver transplantation is necessary at a later age. [5] [10]
Neonatal cholestasis lasted no more than one year in some patients or lasted until the age of 6/7 years in some cases. In recent decades, cholestatic episodes have lasted a shorter time than before 1970. There has also been a decline in rickets, growth retardation, and neuropathy over time. The reasons for this are improved nutritional habits, vitamin and cholestyramine supplementation. Nevertheless, it is not yet possible to prevent serious liver disease. [10]
The first reported cases of Aagenaes syndrome were described in a study in 1968 from the southwest of Norway. [12] [13] Four out of five children born before 1939 died of bleeding in the first weeks of life. Vitamin K was introduced this year, after the birth of another four children after 1939. When these children received one dose of this vitamin, three of them died at the age of 5–9 months. The confirmed cause of death in one or two children in this group was bleeding. The remaining seven children, born in 1935 and in 1942–1966, who were part of a study published in 1968, were alive at the time. [12]
Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme metabolism, liver dysfunction, or biliary-tract obstruction. The prevalence of jaundice in adults is rare, while jaundice in babies is common, with an estimated 80% affected during their first week of life. The most commonly associated symptoms of jaundice are itchiness, pale feces, and dark urine.
Liver function tests, also referred to as a hepatic panel or liver panel, are groups of blood tests that provide information about the state of a patient's liver. These tests include prothrombin time (PT/INR), activated partial thromboplastin time (aPTT), albumin, bilirubin, and others. The liver transaminases aspartate transaminase and alanine transaminase are useful biomarkers of liver injury in a patient with some degree of intact liver function.
Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune disease of the liver. It results from a slow, progressive destruction of the small bile ducts of the liver, causing bile and other toxins to build up in the liver, a condition called cholestasis. Further slow damage to the liver tissue can lead to scarring, fibrosis, and eventually cirrhosis.
Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts, which normally allow bile to drain from the gallbladder. Affected individuals may have no symptoms or may experience signs and symptoms of liver disease, such as yellow discoloration of the skin and eyes, itching, and abdominal pain.
Alagille syndrome (ALGS) is a genetic disorder that affects primarily the liver and the heart. Problems associated with the disorder generally become evident in infancy or early childhood. The disorder is inherited in an autosomal dominant pattern, and the estimated prevalence of Alagille syndrome is 1 in every 30,000 to 1 in every 40,000 live births. It is named after the French pediatrician Daniel Alagille, who first described the condition in 1969. Children with Alagille syndrome live to the age of 18 in about 90% of the cases.
Cholestasis is a condition where the flow of bile from the liver to the duodenum is impaired. The two basic distinctions are:
Dubin–Johnson syndrome is a rare, autosomal recessive, benign disorder that causes an isolated increase of conjugated bilirubin in the serum. Classically, the condition causes a black liver due to the deposition of a pigment similar to melanin. This condition is associated with a defect in the ability of hepatocytes to secrete conjugated bilirubin into the bile, and is similar to Rotor syndrome. It is usually asymptomatic, but may be diagnosed in early infancy based on laboratory tests. No treatment is usually needed.
Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts.
Progressive familial intrahepatic cholestasis (PFIC) is a group of familial cholestatic conditions caused by defects in biliary epithelial transporters. The clinical presentation usually occurs first in childhood with progressive cholestasis. This usually leads to failure to thrive, cirrhosis, and the need for liver transplantation.
Lipoprotein-X (Lp-X) is an abnormal low density lipoprotein found in cholestasis.
Neonatal cholestasis refers to elevated levels of conjugated bilirubin identified in newborn infants within the first few months of life. Conjugated hyperbilirubinemia is clinically defined as >20% of total serum bilirubin or conjugated bilirubin concentration greater than 1.0 mg/dL regardless of total serum bilirubin concentration. The differential diagnosis for neonatal cholestasis can vary extensively. However, the underlying disease pathology is caused by improper transport and/or defects in excretion of bile from hepatocytes leading to an accumulation of conjugated bilirubin in the body. Generally, symptoms associated with neonatal cholestasis can vary based on the underlying cause of the disease. However, most infants affected will present with jaundice, scleral icterus, failure to thrive, acholic or pale stools, and dark urine.
Intrahepatic cholestasis of pregnancy (ICP), also known as obstetric cholestasis, cholestasis of pregnancy, jaundice of pregnancy, and prurigo gravidarum, is a medical condition in which cholestasis occurs during pregnancy. It typically presents with itching and can lead to complications for both mother and fetus.
ATP-binding cassette, sub-family B member 11 (ABCB11), also known as the bile salt export pump (BSEP), is a protein which in humans is encoded by the ABCB11 gene.
The ATP-binding cassette 4 (ABCB4) gene encodes multidrug resistance protein 3. ABCB4 is associated with progressive familial intrahepatic cholestasis type 3 and intrahepatic cholestasis of pregnancy.
Elevated alkaline phosphatase occurs when levels of alkaline phosphatase (ALP) exceed the reference range. This group of enzymes has a low substrate specificity and catalyzes the hydrolysis of phosphate esters in a basic environment. The major function of alkaline phosphatase is transporting chemicals across cell membranes. Alkaline phosphatases are present in many human tissues, including bone, intestine, kidney, liver, placenta and white blood cells. Damage to these tissues causes the release of ALP into the bloodstream. Elevated levels can be detected through a blood test. Elevated alkaline phosphate is associated with certain medical conditions or syndromes. It serves as a significant indicator for certain medical conditions, diseases and syndromes.
A liver support system or diachysis is a type of therapeutic device to assist in performing the functions of the liver. Such systems focus either on removing the accumulating toxins, or providing additional replacement of the metabolic functions of the liver through the inclusion of hepatocytes to the device. A diachysis machine is used for acute care i.e. emergency care, as opposed to a dialysis machine which are typically used over the longer term. These systems are being trialed to help people with acute liver failure (ALF) or acute-on-chronic liver failure.
Bilirubin glucuronide is a water-soluble reaction intermediate over the process of conjugation of indirect bilirubin. Bilirubin glucuronide itself belongs to the category of conjugated bilirubin along with bilirubin di-glucuronide. However, only the latter one is primarily excreted into the bile in the normal setting.
Odevixibat, sold under the brand name Bylvay among others, is a medication for the treatment of progressive familial intrahepatic cholestasis. It is taken by mouth. Odevixibat is a reversible, potent, selective inhibitor of the ileal bile acid transporter (IBAT). It was developed by Albireo Pharma.
Hyperbilirubinemia is a clinical condition describing an elevation of blood bilirubin level due to the inability to properly metabolise or excrete bilirubin, a product of erythrocytes breakdown. In severe cases, it is manifested as jaundice, the yellowing of tissues like skin and the sclera when excess bilirubin deposits in them. The US records 52,500 jaundice patients annually. By definition, bilirubin concentration of greater than 3 mg/dL is considered hyperbilirubinemia, following which jaundice progressively develops and becomes apparent when plasma levels reach 20 mg/dL. Rather than a disease itself, hyperbilirubinemia is indicative of multifactorial underlying disorders that trace back to deviations from regular bilirubin metabolism. Diagnosis of hyperbilirubinemia depends on physical examination, urinalysis, serum tests, medical history and imaging to identify the cause. Genetic diseases, alcohol, pregnancy and hepatitis viruses affect the likelihood of hyperbilirubinemia. Causes of hyperbilirubinemia mainly arise from the liver. These include haemolytic anaemias, enzymatic disorders, liver damage and gallstones. Hyperbilirubinemia itself is often benign. Only in extreme cases does kernicterus, a type of brain injury, occur. Therapy for adult hyperbilirubinemia targets the underlying diseases but patients with jaundice often have poor outcomes.
Bile acid synthesis disorders (BASDs) are rare metabolic disorders characterized by defects in the synthesis of bile acids, which are crucial for cholesterol breakdown and the absorption of fats and fat-soluble vitamins. These disorders can lead to the accumulation of abnormal bile acids and intermediary metabolites, causing damage to various organs.