Medical conditions that only affect a small portion of the population are known as rare diseases. A disease is deemed rare by the World Health Organization (WHO) if it affects fewer than 1 in 2,000 people. More than 7,000 rare diseases have been identified in India, where it is thought that 70 million people are afflicted. Some rare diseases affect newborns as well. Let’s know more about rare diseases in newborns.

Nearly 74000 babies are born every day in India, of which approximately 74 are born with Inborn Errors of Metabolism (IEM). As a result, more than 27000 infants require specialist nutrition and medical care each year. The burden of infant mortality is significantly increased by these factors, even though their individual frequency is relatively low. The affected children are at risk for mental retardation, epilepsy, and serious deficiencies that could even result in mortality if the necessary nutrition is not provided or if delays are brought on by imports of special medical foods.

Rare diseases in newborns in India

Following are the few rare genetic diseases in newborns prevalent in India:

1. Congenital adrenal hyperplasia

One in 10,000 to one in 20,000 babies are born with Congenital Adrenal Hyperplasia (CAH), an autosomal recessive condition. CAH is a collection of genetic diseases affecting the adrenal glands, a pair of walnut-sized organs above the kidneys. The body’s reaction to stress or illness is controlled by the hormone cortisol, which is produced by the adrenal glands. The screening positive rate of this disease is 1 in 5762 out of 104,066 babies in the Indian population. The classic form of CAH manifests as an adrenal crisis in both boys and girls or as genital ambiguity in newborn females (caused by an excess of sex hormones and their derivatives).

2. Galactosemia

Galactose metabolism disorder is brought on by a lack of galactose-1- enzyme. GALT stands for phosphate uridyltransferase. Most babies who are affected show severe symptoms like vomiting, diarrhoea, and hypoglycemia. Babies affected with this disorder may experience jaundice, and cataracts within a couple of weeks. Severe liver diseases like hepatosplenomegaly, cirrhosis, coagulopathy and abnormal liver function tests, kidney tubular injury, ascites, and brain injury are some of the common complications of the disease.

3. Maple syrup urine disease (MSUD)

A rare inborn error of amino acid metabolism and has autosomal recessive inheritance with a reported incidence of 1 in 1,85,000 infants. MSUD is caused by a deficiency of branched-chain alpha-ketoacid dehydrogenase complex. This leads to the accumulation of branch-chained amino acids in the blood causing, central nervous system (CNS) symptoms. Neurological symptoms commonly include lethargy, irritability, poor feeding, apnea, opisthotonus, and ‘bicycling’ movements. Since neurological symptoms are frequently vague and subtle, these newborns are frequently overlooked in the early neonatal period and later present with worsening obtundation, coma, and respiratory failure. This presentation is more prevalent in low- and middle-income countries where neonatal direct blood spot screening for inborn metabolic errors is not widely used.

4. Phenylketonuria

A hereditary condition called phenylketonuria (also referred to as PKU) causes the blood to contain more of the amino acid phenylalanine. An amino acid known as phenylalanine is a component of proteins and is ingested through food. Additionally, some artificial sweeteners and all proteins contain it. If PKU is left untreated, phenylalanine can accumulate in the body to dangerous levels, leading to intellectual disability and other serious health issues.

From mild to severe, PKU can present various signs and symptoms. Classic PKU is the name given to the most severe variation of this disorder. Before they turn a few months old, infants with classic PKU seem normal. These kids become intellectually disabled if they do not receive treatment. Typical symptoms of the condition include seizures, delayed development, behavioural issues, and psychiatric disorders. A side effect of having too much phenylalanine in the body in untreated people may be a musty or mouse-like odour. Children with classic PKU are more likely to have eczema and lighter skin and hair than unaffected family members.

Other rare diseases that may also affect newborns

Other rare neonatal genetic disorders observed in the Indian population are:

• Duchenne muscular dystrophy
• Spinal muscular atrophy
• Wilson’s Disease
• Cystic fibrosis
• Intellectual disability
• Skeletal dysplasia
• Glycogen storage disorder
• Krabbe Disease
• Fabry Disease
• Beta thalassemia trait