Health Special Needs

Inborn Errors Of Metabolism - Types, Symptoms, Medical Tests & Management

Dr Surbhi Saini
0 to 1 years

Created by Dr. Surbhi Saini
Updated on Nov 22, 2018

Inborn Errors Of Metabolism Types Symptoms Medical Tests Management

A single gene is more than sufficient to turn the happiness of a new mom/father into grief. Inborn errors of metabolism are rare heterogeneous group of genetic disorders that occur due to spontaneous mutations in genes leading to defects in metabolic functions. In this blog, I'll explain the types, symptoms and newborn screening tests. Read on...

Common inborn errors of metabolism are:


Phenylalanine (PHE) is an amino acid which is used for protein synthesis or it is converted to other amino acid.

PKU is an autosomal recessive disorder caused due to mutation in the gene coding .PKU is characterised by accumulation of phenyl ketones in the urines of affected individuals.untreated PKU is associated with an abnormal phenotype that includes microcephaly,growth failure,intellectual impairment,seizures,delayed development.


  • Strong musty or mousy odor of urine and sweet

  • Light colored hair and skin

  • Small head and low birth weight

  • Hair loss


maple syrup urine disease is an inborn error of metabolism,characterised by defects in the normal activity of enzyme ,branched chain alpha ketoacid dehydrogenase(BCKAD) complex.

BCAAs catabolism is essential for the normal physiological functions, and increase in its level causes toxicity in the skeletal muscle and brain tissue


  • Irritability and lethargy

  • Poor feeding

  • Apnea

  • Eeizures

  • Intellectual disability

  • Developmental delay

  • Liver failure

  • Sweet smelling urine,an odor similar to maple syrup

  • Encephalopathy


CH is caused due to dysgenesis(problem with thyroid gland development) or dyshormonogenesis(defect in synthesis of thyroid hormone) that is present at birth.



GD is most common lysosomal storage diseases in India. it occurs due to accumulation of enzyme glycosylceramide and other glycolipids in lysosomes of macrophages found essentially in spleen, liver, bone marrow, and brain.


Newborn Screening Tests

A newborn screening test involves blood sample that is taken from baby’s heel as soon as possible after 48hrs of birth.few of the named tests are:

  • Ferric acid test

  • Dinitrophenylhydrazine test

  • Amino acid profile

  • Neonatal phenylketonuria

  • Congenital adrenal hyperplasia test

  • Galactosemia test


Early diagnosis along with nutritional modification management helps in reducing morbidity and mortality.

Supply of essential nutrients and having a disease specific diet is a must to improve the condition.taking pharmacologic regime is recommended.long term screening is advised for potential disease complication.

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