Diseases

Hyperaldosteronism familial type 2

Type 2 familial hyperaldosteronism, inherited as an autosomal dominant trait, causes hypertension secondary to primary aldosteronism that is not suppressed with dexamethasone. Patients present with an adrenal adenoma that secretes aldosterone. The observation of several families affected suggests that the molecular mechanism may be different than in type I familial hyperaldosteronism, but remains to be identified. Diagnostic suspicion should lead to the screening of patients by determining the aldosterone/renin ratio.

Hyperaldosteronism- familial type 1

Type I familial aldosteronism also called dexamethasone suppressible aldosteronism is a rare disorder inherited as an autosomal dominant trait. It is due to the ectopic expression of the aldosterone synthase in the fascicular zone of the adrenal gland. It is marked with early severe hypertension (often occurring before the age of 20), biological signs of primary aldosteronism of variable intensity, and an abnormal elevated level of 18-oxo- and 18-hydroxycortisol. The molecular defect is a recombination on the long arm of chromosome 8 leading a duplication-fusion between the 5' end of the gene coding for the 11 beta-hydroxylase (CYP11B1) and the 3' end of the gene coding for the aldosterone synthase (CYP11B2), two very similar (93%) and very closely located genes. All the modifications are located before the exon 5 of CYP11B2 which encodes amino acids allowing the aldosterone synthase function. The hybrid gene has the promoting part of CYP11B1, ACTH-sensitive, and the coding part of CYP11B2. This leads an excessive mineralocorticoids synthesis in the adrenal glands, governed by the hypothalamohypophyseal axis. Diagnosis and familial screening consist in providing evidence of the hybrid gene by Southern blot and/or PCR. Urinary tests show an important elevation of 18-oxo- and 18-hydroxycortisol. Once the diagnosis is ascertained, a specific treatment to slow the production of aldosterone is given; it combines small doses of dexamethasone and an anti-aldosterone

Hyperammonemia due to NAGS deficiency

Hyperammonemia due to N-Acetylglutamate synthase (NAGS) deficiency is a metabolic disturbance characterised by an excess amount of ammonia in the blood. Children with this severe urea cycle disorders typically show symptoms directly after the first 24 hours of life. Symptoms may include vomiting, lethargy, seizures, respiratory distress and coma. The basic tests to make the diagnosis are the measurement of blood ammonia, plasma amino acids and urine organic acids concentrations. Severe consequences can be avoided through direct medication in combination with a strict diet.

Hyperandrogenism

Excessive levels of androgen (male sex hormones) that can occur in males and females

Hyperbilirubinemia type 1

: Better known as Gilbert's disease, a common but harmless genetic condition in which a liver enzyme essential to the disposal of bilirubin (the chemical that results from the normal breakdown of hemoglobin from red blood cells) is abnormal. (The errant enzyme is called UDP- glucuronosyltransferase).

Hyperbilirubinemia type 2

Hyperbilirubinemia, also called neonatal jaundice, is the result of hemolytic processes in the neonate. It’s marked by elevated serum bilirubin levels and mild jaundice and can be physiologic (with jaundice the only symptom) or pathologic (resulting from an underlying disease). Physiologic jaundice tends to be more common and more severe in certain ethnic groups (Chinese, Japanese, Koreans, Native Americans), whose mean peak of unconjugated bilirubin is approximately twice that of the rest of the population. Physiologic jaundice is self-limiting; the prognosis for pathologic jaundice varies, depending on the cause.

Hypercalciuria- childhood idiopathic

A rare disorder occurring in children for no detectable reason where excess calcium is excreted through the urine resulting in the development of stones in the urinary tract.

Hypercementosis

A tooth disorder where excess cementum (bony covering of tooth root) is deposited on the roots of teeth. One or more teeth may be affected. Causes of excess cementum deposit include localized inflammation and certain metabolic disorders.

Hypercholesterolemia- autosomal dominant- type B

Autosomal dominant type IIa hypercholesterolaemia (ADH) is characterised by an elevation of total plasma cholesterol associated with increased LDL particles.Numerous different molecular defects have been identified in the LDL receptor (LDLR) and few specific mutations in the apolipoprotein B (APOB) gene resulting in familial hypercholesterolaemia and familial defective apoB-100 respectively.

Hyperchylomicronemia

* Triglycerides (TG) are fat (lipid) molecules that are made in the body from other sources such as carbohydrates, or are derived from food. Once TGs are absorbed through the intestines or made in the liver, they are carried via lipoproteins (carrier molecules) to tissues for use as fuel, and to fat cells (adipose tissue) for storage and later use, when energy is needed between meals. * High levels of TGs in the blood create a condition referred to as hypertriglyceridemia. Elevated levels of TGs can slow the flow of blood, and is now recognized as independent risk factor for heart disease -- the number one killer of people in the United States. * There are various types and subtypes of hypertriglyceridemia (I-V) based on the cause, lipid type, and clinical presentation of associated disorders. For example, type IV is associated with high VLDL, a major lipoprotein carrier that transports triglycerides across cell membranes and throughout the body.

Hypereosinophilic syndrome

Hypereosinophilic syndrome is a group of rare blood disorders characterized by increased levels of eosinophils (a type of white blood cell that plays a role in the human immune system) persisting for more than six months. The signs and symptoms are due to involvement of several internal organs and there is usually no evidence of parasites, allergy, or other known causes of an elevated eosinophil count. This condition largely occurs in males, typically at middle age. It usually presents with fever, weight loss, fatigue, and rash. An enlarged liver and spleen and liver is often present. The lungs, kidneys, heart, and nervous system can also be affected.

Hyperexplexia hereditary

Hyperexplexia is a rare autosomal dominant, hereditary, neurological disorder that may affect infants as newborns (neonatal) or prior to birth (in utero). It may also affect children and adults. Individuals with this disorder have an excessive startle reaction to sudden unexpected noise, movement, or touch. Symptoms include extreme muscle tension (stiffness or hypertonia) that can cause the affected person to fall stiffly, like a log, without loss of consciousness. Exaggeration of reflexes (hyperreflexia), and an unstable way of walking (gait) may also occur.

Hyperglycerolemia

A genetic condition where an enzyme deficiency (glycerol kinase) results in an accumulation of glycerol in the body as well as it's excretion through the urine.

Hyperglycinemia- isolated nonketotic type 2

Non ketotic hyperglycinemia with is relatively frequent among inborn errors of newborns. It is transmitted as an autosomal recessive trait. It affects hepatic glycine cleavage, which is the main source of monocarbon radicals. Onset is generally neonatal with coma, severe hypotonia, myoclonic seizures, and microcephaly. The disease usually progresses to severe mental retardation and tetrapyramidal syndrome. The electroencephalogram yields a characteristic hypoactive and pseudoperiodic chart with burts suppression. Biological findings are massive levels of glycine in plasma, urine, and especially cephalospinal fluid, while serine is low. The diagnosis is confirmed by measuring enzymatic activity in the liver. A few cases with later onset have been described (patients present with aspecific encephalopathy), as well as transient neonatal cases, which first present with a favourable disease course, whose long term outcome is finally disappointing. Treatment is based on sodium benzoate and dextromethorphane, but its efficiency has not been demonstrated. Genes encoding N or P subunit may carry different mutations. Antenatal diagnosis using a chorion villus sample may be performed by studying glycine cleavage (not reliable method) or by gene analysis if the mutation is known

Hyperhomocysteinemia

Hyperhomocysteinemia is a medical condition characterized by an abnormally large level of homocysteine in the blood. As a consequence of the biochemical reactions in which homocysteine is involved, deficiencies of the vitamins folic acid, pyridoxine (B6), or B12 can lead to high homocysteine levels. Supplementation with pyridoxine, folic acid, B12 or trimethylglycine (betaine) reduces the concentration of homocysteine in the bloodstream.

Hyperimidodipeptiduria

A very rare genetic disorder characterized by an excessive level of imidodipeptides in the urine due to a deficiency of the enzyme prolidase

Hyperimmunoglobinemia D with recurrent fever

Hyperimmunoglobulinemia D with recurrent fever (commonly abbreviated as HIDS) is a periodic fever syndrome originally described in 1984 by the internist Prof. Jos van der Meer, then at Leiden University Medical Centre. No more than 300 cases have been described worldwide.

Hyperinsulinemic hypoglycemia- familial- 1

A disorder where too much insulin causes low blood sugar in infants. Prompt treatment is needed to avoid the brain being damaged by repeated periods of low blood sugar. The various types of familial hyperinsulinemic hypoglycemia are distinguished by their genetic origin. HHF1 is due to a mutation in the gene for SUR1 (surfonlyurea receptor 1) on chromosome 11p15.1.

Hyperkalemic periodic paralysis

Hyperkalemic periodic paralysis (HYPP), also known as Impressive Syndrome, is an inherited autosomal dominant disorder which affects sodium channels in muscle cells and the ability to regulate potassium levels in the blood. It is most commonly associated with horses, but also occurs in humans, where it is also called Gamstorp episodic adynamy.

Hyperkeratosis lenticularis perstans

Flegel originally described hyperkeratosis lenticularis perstans (HLP) in 1958 as red-brown papules with horny scales of irregular outline measuring 1-5 mm in diameter and up to 1 mm in depth. Lesions are located primarily on the dorsal feet and lower legs, with a decreasing likelihood of manifestation proximally. Most cases have been reported in Europe.

Hyperlipoproteinemia type 1

Hyperlipoproteinemia type 1 is a genetic disorder characterized by abnormal lipid (chylomicrons and high triglyceride lipids) breakdown which results in its accumulation in the blood. The disorder is caused by the reduced or absent activity of the enzyme lipoprotein lipase. The severity of the condition is determined by the degree of the deficiency and treatment. The disorder tends to run in families (familial).

Hyperlipoproteinemia type 3

A rare genetic disorder characterized by the body's impaired ability to break down certain lipids (triglycerides) which results in their buildup in the blood.