Newborn Screening Of Inherited Metabolic Disorders

Some newborns may appear normal and healthy, but they actually carry certain disease-causing genes. If left untreated, these defective genes can result in permanent physical and mental retardation or even death. Early detection of the disease and appropriate intervention, therefore, can avoid irreversible damages to the infants' organs, mental development and may help to regain a normal and healthy life.


We currently provide genetic testing for 43 types of inherited metabolic disorders, and the coverage is still increasing. The total incident rate of these metabolic disorders ranges from 1/4000 to 1/3000; some of these diseases show regional variation with particularly high incident rates in certain areas. Early detection and treatment of these diseases is therefore of particular importance

Commom Disease

Phenylketonuria (PKU)

A very common form of inherited metabolic disorder caused by a lack of the hepatic enzyme phenylalanine hydroxylase (PAH), which is involved in the metabolism of the amino acid phenylalanine to tyrosine. Newborn infants, without feeding, do not exhibit clinical symptoms. Due to PAH deficiency, however, blood concentration of phenylalanine increases as feeding takes place and the accumulation of metabolites leads to a gradual manifestation of clinical symptoms. If left untreated, PKU results in mental retardation, impaired physical development pale hair and skin, and a "musty or mousy" odour of the body and urine. Organic Acidemia Common Disease

Methylmalonic Acidemia (MMA)

Methylmalonic Acidemia is the most common form of organic academia and it can only be tested by spectrometry. Clinical manifestations include depression, hypersomnia, irritability, convulsion, mental and physical retardation, hypotonia, ataxia, optic nerve atrophy, and epilepsy. Methylmalonic academia has no specific clinical symptoms and therefore often causes misdiagnosis initially.

Fatty Acid Oxidation Deficiency

Common disease Medium-chain acyi-CoA dehydrogenase (MCAD) deficiency MCAD deficiency is a common disorder of the fatty acid oxidation process caused by a lack of functional medium-chain acyl-coenzyme A dehydrogenase. Initial onset of the disease can be very serious and often causes sudden death. Most cases occur during 3 to 15 months after birth with pathological changes of hepatic steatosis and cerebral oedema. All reported cases of infant sudden death had occurred prior to diagnosis, making new born screening before disease outbreak a key preventive measure.