- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 1/2. (PMID:9384616)
- Hypertriglyceridemia (HP:0002155): An abnormal increase in the level of triglycerides in the blood. Evidence: PCS. Frequency: 3/5. (PMID:9384616;PMID:8896567)
- Reduced hepatic phosphorylase kinase activity (HP:6000333): Activity of phosphorylase kinase in liver tissue below the lower limit of normal. Phosphorylase kinase (PhK) has a major regulatory role in the breakdown of glycogen. The enzyme PhK comprises four copies each of four subunits, encoded by PHKA1, PHKA2, PHKB, and PHKG. Evidence: PCS. (PMID:21634085)
- 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: PCS. Frequency: 2/3. (PMID:8896567)
- 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: 1/2. (PMID:9384616)
- Cirrhosis (HP:0001394): A chronic disorder of the liver in which liver tissue becomes scarred and is partially replaced by regenerative nodules and fibrotic tissue resulting in loss of liver function. Evidence: PCS. Frequency: 2/2. (PMID:9384616)
- Hepatomegaly (HP:0002240): Abnormally increased size of the liver. Evidence: PCS. Frequency: 3/3. (PMID:8896567)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 3/3. (PMID:8896567)
- Reduced tissue phosphorylase kinase activity (HP:6000832): Concentration or activity of phosphorylase kinase below the lower limit of normal. This enzyme can be measured in multiple tissues including leukocytes and cultured fibroblasts. Evidence: TAS. (OMIM:613027)
- Fasting hypoglycemia (HP:0003162). Evidence: PCS. Frequency: 1/3. (PMID:8896567)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 2/3. (PMID:8896567)
- Bile duct proliferation (HP:0001408): Proliferative changes of the bile ducts. Evidence: PCS. Frequency: 1/3. (PMID:8896567)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: IEA. Frequency: 1/2. (PMID:9384616)
- 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:8896567)
- Hypoglycemia (HP:0001943): A decreased concentration of glucose in the blood. Evidence: PCS. Frequency: 1/2. (PMID:9384616)
- Ketosis (HP:0001946): Presence of elevated levels of ketone bodies in the body. Evidence: IEA. (OMIM:613027)
- Postnatal growth retardation (HP:0008897): Slow or limited growth after birth. Evidence: PCS. Frequency: 1/2. (PMID:9384616)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: PCS. Frequency: 3/3. (PMID:8896567)
- 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: PCS. Frequency: 4/5. (PMID:9384616;PMID:8896567)
- Splenomegaly (HP:0001744): Abnormal increased size of the spleen. Evidence: TAS. (OMIM:613027)
- Increased hepatic glycogen content (HP:0006568): An increase in the amount of glycogen stored in hepatocytes compared to normal. Evidence: PCS. Frequency: 2/2. (PMID:9384616)
- Lactic acidosis (HP:0003128): An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids. Evidence: IEA. (OMIM:613027)
These phenotypes are associated with the disease glycogen storage disease IXc (OMIM:613027).