MOLECULAR GENETICS

TMS (Tandem Mass Spectrometry) / GCMS (Gas Chromatography-Mass Spectrometry) / Other Biochemical and Molecular Assays
This comprehensive newborn screening panel utilizes a combination of advanced analytical techniques to detect a wide range of congenital, genetic, and metabolic disorders. Each methodology is chosen for its specific strengths in identifying different types of biomarkers: * TMS (Tandem Mass Spectrometry): This is the primary method for screening a large number of inborn errors of metabolism (IEMs) from a dried blood spot. TMS is highly sensitive and specific for detecting abnormal levels of various metabolites (amino acids, acylcarnitines, succinylacetones, etc.) in a single run. * Conditions Screened (52 conditions by TMS): This typically covers a broad spectrum of disorders, including: * Amino Acid Disorders (Aminoacidopathies): Phenylketonuria (PKU), Maple Syrup Urine Disease (MSUD), Homocystinuria, Tyrosinemia (Types I, II, III), Citrullinemia (Type I, II), Argininemia, Argininosuccinic Acidemia, etc. * Organic Acid Disorders (Organic Acidemias): Propionic Acidemia, Methylmalonic Acidemia, Isovaleric Acidemia, Glutaric Acidemia Type I, 3-Methylcrotonyl-CoA Carboxylase Deficiency, Multiple Carboxylase Deficiency, etc. * Fatty Acid Oxidation Disorders: Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD), Very Long-Chain Acyl-CoA Dehydrogenase Deficiency (VLCADD), Carnitine Uptake Defect, Carnitine Palmitoyl Transferase Deficiencies, etc. * GCMS (Gas Chromatography-Mass Spectrometry): This method is employed for analyzing urine samples, particularly for a vast array of organic acids and other metabolites that might not be comprehensively covered by TMS or are more effectively detected in urine. GCMS provides a metabolic "fingerprint" and is highly effective for diagnosing various organic acidurias, amino acidurias, and other metabolic disorders. * Conditions Screened (111 conditions by GCMS): This extended urine panel covers a wide range of metabolic conditions, including: * Disorders of Organic Acid Metabolism: Many organic acidurias not explicitly listed under TMS. * Disorders of Purine and Pyrimidine Metabolism: Lesch-Nyhan syndrome, Xanthinuria, etc. * Disorders of Carbohydrate Metabolism: Specific carbohydrate abnormalities. * Other Metabolic Disorders: Glycerol Kinase Deficiency, certain peroxisomal disorders, TCA cycle abnormalities, etc. (The exact list of 111 conditions can vary slightly between labs, but it's extensive). * Other Basic Biochemical/Molecular Assays: These are typically performed on dried blood spots or whole blood and cover the "basic" conditions, often including: * 7 Basic Conditions (often considered core in India): * Congenital Hypothyroidism (CH): Detected by elevated Thyroid Stimulating Hormone (TSH) and/or low T4 levels. * Congenital Adrenal Hyperplasia (CAH): Detected by elevated 17-hydroxyprogesterone (17-OHP). * G6PD Deficiency (Glucose-6-Phosphate Dehydrogenase Deficiency): Detected by measuring G6PD enzyme activity. * Galactosemia: Detected by elevated total galactose or galactose-1-phosphate. * Biotinidase Deficiency (BTD): Detected by measuring biotinidase enzyme activity. * Cystic Fibrosis (CF): Often screened by immunoreactive trypsinogen (IRT) with reflex DNA testing for common mutations if IRT is elevated. * Phenylketonuria (PKU): (Also covered by TMS, but often listed as a "basic" due to its historical importance and treatability). Sometimes also includes screening for hemoglobinopathies like Sickle Cell Disease and Beta Thalassemia using HPLC or isoelectric focusing, which might be implicitly covered by "basic" or separately analyzed depending on the panel. This combined approach offers a highly comprehensive screening for a vast number of treatable conditions, allowing for early detection and intervention before symptoms develop, which is crucial for preventing severe intellectual disability, developmental delays, organ damage, or even death.

Dried Blood Spot (DBS) / Whole Blood (WB) in EDTA & URINE
(This panel requires multiple sample types for comprehensive screening): * Dried Blood Spot (DBS): A few drops of blood collected via a heel prick, dried on a special filter paper card. This is the standard sample for TMS and many basic biochemical tests. * Whole Blood (WB) in EDTA: May be requested for specific basic tests or as a backup/confirmatory sample for certain conditions. * URINE Sample: A urine sample is collected (e.g., using a urine bag for infants) specifically for the GCMS analysis.

Proper timing and sample collection are crucial for accurate newborn screening results.
* Optimal Timing: The blood sample (DBS) is typically collected between 24 to 72 hours (1-3 days) of life, ideally after 24 hours of milk feeding (breast milk or formula), to ensure the metabolic pathways are active and metabolites are detectable. For premature or sick babies, special considerations might apply. * Milk Feeding: Ensure the baby has received at least 24 hours of adequate milk feeding prior to blood collection. This is important for the accumulation of metabolites, especially for amino acid and fatty acid oxidation disorders. * Hydration: Ensure the baby is well-hydrated for urine sample collection. * No Fasting Required: Fasting is not required and should be avoided for newborns. * Parental Consent: Informed consent from parents is typically obtained before performing the screening. * Follow-up Plan: Parents should be informed about the expected turnaround time and the process for receiving results, including what happens if a "positive" (abnormal) screen result occurs (which requires confirmatory testing).