- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: TAS. (OMIM:613070)
- Hepatomegaly (HP:0002240): Abnormally increased size of the liver. Evidence: PCS. Frequency: 13/13. (PMID:19732863)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 10/13. (PMID:19732863)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: TAS. (OMIM:613070)
- Hypoalbuminemia (HP:0003073): The concentration of albumin in the blood circulation is below the lower limit of normal. Evidence: PCS. Frequency: 13/13. (PMID:19732863)
- Abdominal distention (HP:0003270): Distention of the abdomen. Evidence: PCS. Frequency: 13/13. (PMID:19732863)
- Elevated circulating alanine aminotransferase concentration (HP:0031964): An abnormally high concentration in the circulation of alanine aminotransferase (ALT). Evidence: PCS. Frequency: 12/12. (PMID:19732863)
- Prolonged prothrombin time (HP:0008151): Increased time to coagulation in the prothrombin time test, which is a measure of the extrinsic pathway of coagulation. The results of the prothrombin time test are often expressed in terms of the International normalized ratio (INR), which is calculated as a ratio of the patient's prothrombin time (PT) to a control PT standardized for the potency of the thromboplastin reagent developed by the World Health Organization (WHO) using the formula: INR is equal to Patient PT divided by Control PT. Evidence: PCS. Frequency: 8/8. (PMID:19732863)
- Irritability (HP:0000737): An emotional state characterized by negative feelings of heightened frustration, annoyance, or feeling upset, often triggered by internal factors (e.g., fatigue, hunger, unfulfilled desires) or external factors (e.g., social or environmental challenges). Irritability may be unpredictable, and is accompanied by a lowered threshold for emotional reactivity and observable features (speech, facial expressions, or psychomotor activity). Evidence: PCS. Frequency: 13/13. Onset: Infantile onset (HP:0003593). (PMID:19732863)
- Mitochondrial respiratory chain defects (HP:0200125). Evidence: PCS. Frequency: 2/2. (PMID:19732863)
- Feeding difficulties in infancy (HP:0008872): Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention. Evidence: PCS. Frequency: 13/13. Onset: Infantile onset (HP:0003593). (PMID:19732863)
- Lacticaciduria (HP:0003648): An increased concentration of lactic acid in the urine. Evidence: PCS. Frequency: 13/13. (PMID:19732863)
- Acute hepatic failure (HP:0006554): Hepatic failure refers to the inability of the liver to perform its normal synthetic and metabolic functions, which can result in coagulopathy and alteration in the mental status of a previously healthy individual. Hepatic failure is defined as acute if there is onset of encephalopathy within 8 weeks of the onset of symptoms in a patient with a previously healthy liver. Evidence: PCS. Frequency: 13/13. Onset: Infantile onset (HP:0003593). (PMID:19732863)
- Death in infancy (HP:0001522): Death within the first 24 months of life. Evidence: PCS. Frequency: 4/13. (PMID:19732863)
- Elevated circulating hepatic transaminase concentration (HP:0002910): Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage. Evidence: IEA. (OMIM:613070)
- Jaundice (HP:0000952): Yellow pigmentation of the skin due to bilirubin, which in turn is the result of increased bilirubin concentration in the bloodstream. Evidence: PCS. Frequency: 13/13. Onset: Infantile onset (HP:0003593). (PMID:19732863)
- Macrovesicular hepatic steatosis (HP:0001403): A form of hepatic steatosis characterized by the presence of large, lipid-laden vesicles in the affected hepatocytes. Evidence: PCS. Frequency: 2/2. (PMID:19732863)
- Decreased circulating IgG concentration (HP:0004315): An abnormally decreased level of immunoglobulin G (IgG) in blood. Evidence: PCS. Frequency: 5/7. (PMID:19732863)
- Lactic acidosis (HP:0003128): An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids. Evidence: PCS. (PMID:19732863)
- Neonatal onset (HP:0003623): Onset of signs or symptoms of disease within the first 28 days of life. Evidence: PCS. Frequency: 3/13. (PMID:19732863)
- Vomiting (HP:0002013): Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions. Evidence: PCS. Frequency: 13/13. Onset: Infantile onset (HP:0003593). (PMID:19732863)
- Increased circulating lactate concentration (HP:0002151): Abnormally increased level of blood lactate (2-hydroxypropanoic acid). Lactate is produced from pyruvate by lactate dehydrogenase during normal metabolism. The terms lactate and lactic acid are often used interchangeably but lactate (the component measured in blood) is strictly a weak base whereas lactic acid is the corresponding acid. Lactic acidosis is often used clinically to describe elevated lactate but should be reserved for cases where there is a corresponding acidosis (pH below 7.35). Evidence: PCS. Frequency: 12/12. (PMID:19732863)
- 3-hydroxydicarboxylic aciduria (HP:0008160): The concentration of 2-hydroxydicarboxylic acid in the urine, normalized for urine concentration, is above the upper limit of normal. Evidence: PCS. Frequency: 13/13. (PMID:19732863)
- Hyperbilirubinemia (HP:0002904): An increased amount of bilirubin in the blood. Evidence: PCS. Frequency: 10/11. (PMID:19732863)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:19732863)
- Microvesicular hepatic steatosis (HP:0001414): A form of hepatic steatosis characterized by the presence of small, lipid-laden vesicles in the affected hepatocytes. Evidence: TAS. (OMIM:613070)
- Dicarboxylic aciduria (HP:0003215): An increased concentration of dicarboxylic acid in the urine. Evidence: PCS. Frequency: 13/13. (PMID:19732863)
These phenotypes are associated with the disease acute infantile liver failure due to synthesis defect of mtDNA-encoded proteins (OMIM:613070).