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 a 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 In-born Metabolism Errors

#1. Phenylketonuria (PKU)

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

PKU is an autosomal recessive disorder caused due to a mutation in the gene coding. PKU is characterized by the 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.

Symptoms of Phenylketonuria

• The strong musty or mousy odor of urine and sweet

• Light-colored hair and skin

• Small head and low birth weight

• Hair loss

#2. Maple Syrup Urine Disease (MSUD)

maple syrup urine disease is an inborn error of metabolism, characterized by defects in the normal activity of the 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

Symptoms of Maple Syrup Urine Disease

• Irritability and lethargy

• Poor feeding

• Apnea

• Seizures

• Intellectual disability

• Developmental delay

• Liver failure

• Sweet-smelling urine, an odor similar to maple syrup

• Encephalopathy

#3. Congenital hypothyroidism (CH)

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

Symptoms of Congenital hypothyroidism

• Hoarse cry

• Feeding difficulty and constipation

• Lethargy

• Poor muscle tone

• Prolonged jaundice

• Umbilical hernia

• Large tongue

• Cold and mottled skin

#4. Gaucher's Disease(GD)

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

Symptoms of Gaucher Disease

• Easy bleeding and bruising

• Excessive fatigue

• Anemia

• Weak bones

• Bone and joint pain

• Hepatosplenomegaly

• Myoclonic seizures

• Lack of coordination and mental degeneration

Newborn Screening Tests

A newborn screening test involves a blood sample that is taken from the 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

Medical Tests & Management

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

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