The imino acids, proline and hydroxyproline, share a renal tubular reabsorptive mechanism with glycine. Iminoglycinuria (IG; 242600), a benign inborn error of amino acid transport, is also a normal finding in neonates and infants under 6 months of age (Chesney, 2001). Early studies of families with iminoglycinuria suggested genetic complexity, with homozygotes developing IG and heterozygotes manifesting only hyperglycinuria (HG) (summary by Broer et al., 2008). A phenotype of combined glucosuria and glycinuria has been described (see 138070).

An increase in the level of hippuric acid in the urine.

Hemorrhage into the parenchyma of the cerebellum.

A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.

A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).

Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.

Infrequent or difficult evacuation of feces.

Abnormally increased size of the liver.

Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions.

A reduced desire to eat.

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.

The complete absence of wakefulness and consciousness, which is evident through a lack of response to any form of external stimuli.

An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.

A state of disinterest, listlessness, and indifference, resulting in difficulty performing simple tasks or concentrating.

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

A life-threatening disorder characterized by delirium, seizures, and neuromuscular changes.

A reduction in erythrocytes volume or hemoglobin concentration.

An abnormal reduction in numbers of all blood cell types (red blood cells, white blood cells, and platelets).

A reduction in the number of circulating thrombocytes.

Osteoporosis is a systemic skeletal disease characterized by low bone density and microarchitectural deterioration of bone tissue with a consequent increase in bone fragility. According to the WHO criteria, osteoporosis is defined as a BMD that lies 2.5 standard deviations or more below the average value for young healthy adults (a T-score below -2.5 SD).

Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.

Lack of breathing with no movement of the respiratory muscles and no exchange of air in the lungs. This term refers to a disposition to have recurrent episodes of apnea rather than to a single event.

Very rapid breathing.

Eczema is a form of dermatitis that is characterized by scaly, pruritic, erythematous lesions located on flexural surfaces.

The presence of inflammation in the pancreas.

An abnormally low number of neutrophils in the peripheral blood.

An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids.

A condition resulting from the excessive loss of water from the body. It is usually caused by severe diarrhea, vomiting or diaphoresis.

A decreased concentration of glucose in the blood.

Metabolic acidosis (MA) is characterized by a fall in blood pH due to a reduction of serum bicarbonate concentration. This can occur as a result of either the accumulation of acids (high anion gap MA) or the loss of bicarbonate from the gastrointestinal tract or the kidney (hyperchloremic MA). By definition, MA is not due to a respirary cause.

An elevated concentration of glycine in the blood.

Propionic acidemia is an autosomal recessive metabolic disorder caused by defective functioning in the mitochondrial enzyme propionyl CoA carboxylase (PCC), resulting in the accumulation of propionic acid metabolites, and dysfunction in the respiratory chain and urea cycle pathways. The disorder is clinically heterogeneous. A neonatal-onset form is characterized by poor feeding, vomiting, and fatigue in the first days of life in a previously healthy infant, and if untreated, may be followed by lethargy, seizures, coma, and death. The neonatal form is frequently accompanied by metabolic acidosis with anion gap, ketonuria, hypoglycemia, hyperammonemia, and cytopenia. A late-onset form in older children and adults has a milder phenotype, is less common, and may present with developmental regression, chronic vomiting, protein intolerance, failure to thrive, hypotonia, and occasionally basal ganglia infarction, which may result in dystonia and choreoathetosis, and cardiomyopathy. Metabolically unstable individuals can have an acute decompensation that resembles the neonatal presentation, often precipitated by a catabolic stress such as infection, injury, or surgery, or an excessive intake of intact (i.e., complete, dietary, or natural) protein. Long-term manifestations of neonatal and late onset of propionic acidemia can include growth impairment, intellectual disability, seizures, basal ganglia lesions, pancreatitis, and cardiomyopathy. Other less common manifestations include optic atrophy, hearing loss, premature ovarian insufficiency, and chronic renal failure (summary by Jurecki et al., 2019).

An increased concentration of ammonia in the blood.