Inborn errors of metabolism (IEM) are an important cause of acute illness in newborns. Presentation may mimic common neonatal conditions such as sepsis. Prompt detection requires a high index of suspicion and the early measurement of biochemical markers such as blood ammonia. Diagnosis is important not only for treatment but also for genetic counselling.
In Neonatal IEM – pregnancy and delivery are generally uneventful. The newborn baby with IEM is normal for few hours or first day to 3-4 days after which the disorder presents due to intake of dietary protein or sugar (Lactose, Fructose). Neonates with IEMs are often misdiagnosed as Sepsis or other disorders. Sepsis often accompanies IEM but may confine the diagnosis. Neonates have limited responses to illness and prominent ones are poor feeding, lethargy, coma, failure to thrive, seizures, acidosis or ketosis. A high index of suspicion and follow-up diagnosis is necessary when the following symptoms are present -
Parental consanguinity (marriages in relation).
Positive Family History
Symptoms onset a few hours to days after feeding (poor feeding, lethargy, seizures, vomiting, diarrhea, coma, hypotonia)
Ketosis, hypoglycemia, acidosis
Unusual odor in the urine
Jaundice
Dysmorphic features
Overview of Newborn Screening (NBS)
Newborn screening (NBS) is a crucial public health initiative that involves testing newborn babies to detect serious, treatable conditions before symptoms appear. This early detection allows for prompt treatment, which can prevent death, disability, and long-term health problems.
NBS typically involves three main components:
Blood Spot Screening (Heel Stick): A few drops of blood are collected from the baby's heel onto a special filter paper. This sample is then tested for a variety of metabolic, endocrine, hemoglobin, and other genetic disorders.
These tests are most effective during the neonatal period, which is why the blood sample is taken 24 to 48 hours after birth. If the initial screening shows any irregularities, the blood is sent for further testing. The full reports are then submitted to the baby's pediatrician or parents, who can then begin treatment and seek counseling based on the findings.
Hearing Screening: This test checks for hearing loss, often using Otoacoustic Emissions (OAE) or Automated Auditory Brainstem Response (AABR) technology.
Pulse Oximetry Screening: A non-invasive test that measures the amount of oxygen in the baby's blood to screen for critical congenital heart defects (CCHD).
Global Status of Newborn Screening
Many countries worldwide have implemented universal newborn screening programs, especially in developed nations. The specific conditions screened for and the level of coverage can vary significantly by country or region.
United States: All 50 states have newborn screening programs, though the number of conditions screened for varies. The U.S. has a Recommended Uniform Screening Panel (RUSP) that provides guidance on a core set of conditions.
European Union: Many EU countries have, or are in the process of implementing, universal NBS programs. Countries like Austria, Belgium, Denmark, Croatia, England, Luxembourg, the Netherlands, and Poland have achieved high levels of coverage.
Australia and New Zealand: Both countries have universal newborn screening programs.
China: China has made significant progress in implementing a universal newborn hearing screening program, with coverage reaching over 94% of newborns by 2020.
Other Countries: Universal or widespread NBS programs also exist in countries such as Canada and Japan.
It's important to distinguish between "universal" (offered to all newborns) and "mandatory" (required by law) screening. In some places, parents can opt out. The list of conditions screened for is not static and is continuously evolving as new technologies and treatments become available. Despite the widespread adoption of NBS in high-income countries, coverage remains limited in many low- and middle-income countries.
Newborn Screening in India
In India, healthcare priorities are still primarily focused on reducing the infant mortality rate and meeting basic infrastructure requirements. The central and state governments have yet to implement a nationwide mandatory screening program for newborns.
Currently, some healthcare centers in India offer NBS as a standard procedure, while others provide it as an option for parents. The states of Goa and Kerala, along with the Union Territories of Chandigarh and Delhi, conduct routine newborn screening. While some regions like Rajasthan (JK Lone Hospital, Jaipur) and Tamil Nadu (Vellore) have had programs in the past, they are no longer active. Many childcare hospitals, however, have adopted routine NBS as part of their standard hospital policy.
Important Considerations
For infants in the Neonatal Intensive Care Unit (NICU) and other high-risk babies, there are special considerations and complexities that must be addressed during the screening process.
Disclaimer: The information provided above has been sourced from various websites and articles. It is not exhaustive to be up-to-date. For medical or clinical advice, it is essential to consult with a physician, geneticist, or metabolic expert. We do not provide genetic counseling or clinical advice.