About hal deficiency

What is hal deficiency?

Histidinemia is a rare hereditary metabolic disorder characterized by a deficiency of the enzyme histidase, which is necessary for the metabolism of the amino acid histidine. The concentration of histidine is elevated in the blood. Excessive amounts of histidine, imidazole pyruvic acid, and other imidazole metabolism products are excreted in the urine. The majority of individuals with histidinemia have no obvious symptoms that would indicate that a person has this disorder (asymptomatic). Histidinemia is inherited as an autosomal recessive trait.

What are the symptoms for hal deficiency?

Histidinemia is considered a benign condition. For years, intellectual disability and speech disorders were associated with histidinemia. However, these findings are now considered coincidental and not due to the metabolic defect of histidinemia because reports of follow-up from newborn screening have demonstrated that the majority of infants with histidinemia do not develop clinical symptoms (asymptomatic). Nevertheless, clinical symptoms have been reported in some patients with histidinemia. To reconcile this with the benign findings from newborn screening, it has been suggested that histidinemia might be a risk factor for the development of CNS problems, and that such problems might develop only in an unfavorable circumstance such as an abnormal perinatal event.

Individuals with histidinemia have elevated levels of the amino acid histidine in the blood and excessive amounts of histidine, imidazole pyruvic acid, and other imidazole metabolism products in the urine. Most people with histidinemia adapt to the presence of excessive histidine in the blood and do not suffer any ill effects.

According to the medical literature, infants born to mothers with histidinemia (maternal histinemia) have exhibited no symptoms.

What are the causes for hal deficiency?

Histidinemia is inherited in an autosomal recessive pattern. Genetic diseases are determined by two genes, one received from the father and one from the mother.

Recessive genetic disorders occur when an individual inherits an abnormal variant of a gene from each parent. If an individual receives one normal gene and one abnormal variant gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the abnormal variant gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier, like the parents, is 50% with each pregnancy. The chance for a child to receive normal genes from both parents is 25%. The risk is the same for males and females.

Researchers believe that histidinemia is due to mutations of the human histidase (HAL) gene.

What are the treatments for hal deficiency?

Histidinemia is considered a benign, asymptomatic disorder that does not require treatment. According to the medical literature, therapy consisting of a carefully monitored histidine-restricted diet was once recommended, but is no longer called for.

Genetic counseling may also be of benefit to affected individuals and their families. Treatment is symptomatic and supportive for coincidental problems.

What are the risk factors for hal deficiency?

HAL deficiency i.e histidine ammonia-lyase (HAL) deficiency or histidase deficiency, hyperhistidinemia or Histidinemia is a rare, autosomal recessive hereditary metabolic disorder.

  • It is caused by a deficiency of the enzyme histidase, which is necessary for metabolizing the amino acid histidine. As a result, elevated levels of histidine are present in the blood.
  • Along with histidine, there are excessive amounts of imidazole pyruvic acid and other imidazole metabolism products that are excreted in the urine.


Histidine is an essential amino acid that is not formed in the body. It is required for,

  • Producing white and red blood cells, producing ferritin and hemoglobin.
  • Reducing inflammation and oxidative stress
  • Helping regulate feeding behavior and energy metabolism
  • Regulating levels of iron, copper, molybdenum, zinc and manganese
  • Producing histamine, a neurotransmitter.
  • Producing carnosine- leads to the reduction of plaque buildup in the arteries.
  • Repairing tissue and wounds.
  • Regulating the pH value of the blood.
  • Protecting the skin by producing urocanic acid, an absorber of UV light.


Conditions
Rheumatoid arthritis,Anaemia,Psychological disorders such as anxiety and schizophrenia,Deafness,Colds and Allergies,Poor growth in infants,Heart and kidney ailments
Drugs
You can get the histidine that your body needs by eating a well-balanced, healthy diet that includes enough protein foods like meat, fish, poultry, eggs, legumes, nuts and seeds. Adults need an amount of 8 to 12 milligrams of histidine per kilogram of body weight, daily. Regulating the amount of histidine-rich food brings the histidine level back to normal.
Symptoms
Behavioural abnormality,Hyperactivity,Psychomotor retardation,Affected skills for learning like reading or writing, coordination, self-control or attention that interfere with the ability to learn

Is there a cure/medications for hal deficiency?

HAL deficiency i.e histidine ammonia-lyase (HAL) deficiency or histidase deficiency, hyperhistidinemia or Histidinemia is a rare, autosomal recessive hereditary metabolic disorder.

  • It is caused by a deficiency of the enzyme histidase, which is necessary for metabolizing the amino acid histidine. As a result, elevated levels of histidine are present in the blood.
  • Along with histidine, there are excessive amounts of imidazole pyruvic acid and other imidazole metabolism products that are excreted in the urine.


Histidine is an essential amino acid that is not formed in the body. It is required for,

  • Producing white and red blood cells, producing ferritin and hemoglobin.
  • Reducing inflammation and oxidative stress
  • Helping regulate feeding behavior and energy metabolism
  • Regulating levels of iron, copper, molybdenum, zinc and manganese
  • Producing histamine, a neurotransmitter.
  • Producing carnosine- leads to the reduction of plaque buildup in the arteries.
  • Repairing tissue and wounds.
  • Regulating the pH value of the blood.
  • Protecting the skin by producing urocanic acid, an absorber of UV light.


Conditions
Rheumatoid arthritis,Anaemia,Psychological disorders such as anxiety and schizophrenia,Deafness,Colds and Allergies,Poor growth in infants,Heart and kidney ailments
Drugs
You can get the histidine that your body needs by eating a well-balanced, healthy diet that includes enough protein foods like meat, fish, poultry, eggs, legumes, nuts and seeds. Adults need an amount of 8 to 12 milligrams of histidine per kilogram of body weight, daily. Regulating the amount of histidine-rich food brings the histidine level back to normal.
Symptoms
Behavioural abnormality,Hyperactivity,Psychomotor retardation,Affected skills for learning like reading or writing, coordination, self-control or attention that interfere with the ability to learn

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