Propionic Acidemia is an autosomal recessive branched-chain organic acidemia, characterized by a deficiency of the propionyl-CoA carboxylase enzyme, which helps in the normal breakdown of several essential amino acids.
Patients may initially present some minor symptoms including poor feeding, vomiting, loss of appetite, hypotonia, and lethargy. Later, most children will show different degrees of motor, social and language delay. They also show more serious medical problems, including neutropenia, cardiac abnormalities, periodic thrombocytopenia, hypogammaglobulinemia, developmental retardation, seizures, and coma. Death is likely, if the condition is not intervened with. In most cases, the condition presents itself in the infantile stage. However, it may also rarely manifest itself in a childhood form, which is less severe, and is triggered by stress conditions, such as fasting, or infections. In the US, recorded incidence of the disease is about 1 in every 35,000 live births. However, in some other populations, the incidence is much higher. These include the Inuit population of Greenland, some Amish communities, and the Saudi population.
A neonate with symptoms that resemble organic acidemia requires biochemical investigations. The most comprehensive method to assess is by using the technique of Gas Chromatography with Mass Spectrometry (GC/MS). This enables the identification of the toxic compounds accumulated in the body. Therapy involves a three pronged strategy. As the first line strategy, protein intake is completely halted and other calorie sources are provided to the patient. For the ketoacidosis, correction involves providing increased carbohydrate calories, bicarbonate replacement, and increased fluid intake. After the condition has somewhat normalized, the patient is restarted on a low protein diet (<1.5g/kg body weight a day). In addition, intermittent administration of antibiotics needs to be provided to partially destroy the gut flora and reduce the propionate production by them. A special low-protein diet needs to be maintained for the rest of the patients' life.