Question: What is (are) Dihydrolipoamide dehydrogenase deficiency ?
Answer: Dihydrolipoamide dehydrogenase (DLD) deficiency is a very rare condition that can vary in age of onset, symptoms and severity. The condition may be characterized by early-onset lactic acidosis and delayed development (most commonly); later-onset neurological dysfunction; or adult-onset isolated liver disease. Signs and symptoms may include lactic acidosis shortly after birth; hypotonia and lethargy in infancy; feeding difficulties; seizures; and various other health issues. Liver problems can range from hepatomegaly to life-threatening liver failure. Symptoms often occur in episodes that may be triggered by illness or other stresses on the body. Many affected infants do not survive the first few years of life; those who survive through early childhood often have growth delay and intellectual disability. Some with onset later in childhood may have neurological dysfunction with normal cognitive development. DLD deficiency is caused by mutations in the DLD gene and is inherited in an autosomal recessive manner.
Source: GARD

Question: What are the symptoms of Dihydrolipoamide dehydrogenase deficiency ?
Answer: What are the signs and symptoms of Dihydrolipoamide dehydrogenase deficiency? The signs and symptoms of dihydrolipoamide dehydrogenase (DLD) deficiency can vary widely among affected people. Early-onset DLD deficiency typically appears in early infancy with decreased muscle tone (hypotonia), lethargy, and lactic acidosis. Lactic acidosis can cause nausea, vomiting, severe breathing problems, and an abnormal heartbeat. Symptoms typically occur in episodes that may be triggered by illness, injury, or other stresses on the body. Affected infants often do not survive their initial episode or may die within the first few years of life during a recurrent episode. Children who live beyond the first two to three years often have growth delays and neurological problems such as intellectual disability, spasticity, ataxia, and seizures. However, normal intellect has been reported in a few people with the early-onset form of DLD deficiency. Isolated liver involvement, which can range from hepatomegaly (enlarged liver) to life-threatening liver failure, can also occur in the newborn period, or as late as the 3rd decade of life. A few people with DLD deficiency have become affected later in childhood with ataxia and dystonia, with normal cognitive development. Rarely, affected people have muscle weakness (particularly during exercise) or a weakened heart muscle (cardiomyopathy). The Human Phenotype Ontology provides the following list of signs and symptoms for Dihydrolipoamide dehydrogenase deficiency. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Aminoaciduria 90% Cognitive impairment 50% Gait disturbance 50% Hepatomegaly 50% Microcephaly 50% Muscular hypotonia 50% Hepatic failure 7.5% Hypoglycemia 7.5% Decreased liver function 5% Elevated hepatic transaminases 5% Ataxia - Autosomal recessive inheritance - Dystonia - Encephalopathy - Feeding difficulties - Hypertrophic cardiomyopathy - Lactic acidosis - Lethargy - Metabolic acidosis - Seizures - Variable expressivity - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Dihydrolipoamide dehydrogenase deficiency ?
Answer: What causes dihydrolipoamide dehydrogenase deficiency? Dihydrolipoamide dehydrogenase (DLD) deficiency is caused by changes (mutations) in the DLD gene. This gene gives the body instructions to make an enzyme called dihydrolipoamide dehydrogenase (DLD). DLD is one part of 3 different groups of enzymes that work together (enzyme complexes). These enzyme complexes are involved in breaking down amino acids commonly found in protein-rich foods, and in other reactions that help to convert energy from food into a form that our cells can use. Mutations in the DLD gene impair the function of DLD, preventing the 3 enzyme complexes from functioning properly. This causes a build-up of molecules that are normally broken down, which in turn leads to tissue damage, lactic acidosis and other chemical imbalances. The brain is especially sensitive to the buildup of molecules and lack of cellular energy, which is why there are neurological problems associated with DLD deficiency.
Source: GARD