Biochemistry Section DOI : 10.7860/JCDR/2018/30035.11515
Year : 2018 | Month : May | Volume : 12 | Issue : 05 Page : BC07 - BC13

Prevalence of Inborn Errors of Metabolism in Neonates

Preeti Sharma1, Pradeep Kumar2, Mayurika S Tyagi3, Rachna Sharma4, PS Dhot5

1 Associate Professor, Department of Biochemistry, Santosh University, Ghaziabad, Uttar Pradesh, India.
2 Professor, Department of Biochemistry, Santosh University, Ghaziabad, Uttar Pradesh, India.
3 Assistant Professor, Department of Pathology, Santosh Medical College and Hospital, Ghaziabad, Uttar Pradesh, India.
4 Lecturer, Department of Biochemistry, T.S. Mishra Medical College and Hospital, Lucknow, Uttar Pradesh, India.
5 Professor, Department of Biochemistry, Santosh University, Ghaziabad, Uttar Pradesh, India.


NAME, ADDRESS, E-MAIL ID OF THE CORRESPONDING AUTHOR: Dr. Preeti Sharma, 23, Arya Nagar, Surajkund Road, Meerut-250001, Uttar Pradesh, India.
E-mail: prcdri2003@yahoo.co.in
Abstract

Introduction

Among the most advanced public health promotion and disease prevention programs, the newborn screening is of paramount importance, seeking timely detection, diagnosis and treatment of genetic disorders which may otherwise lead to serious consequences upon the health of newborn.

Aim

To evaluate the prevalence of Inborn Error of Metabolism (IEM) disorders among neonates of various ethnic or racial groups from east, west, north and south, zones of India through newborn screening.

Materials and Methods

A cross-divtional, population based prospective study was conducted at PreventiNe Life Care Laboratories, Navi Mumbai, Maharashtra, India. Study was conducted for a period of three years from October 2012 to November 2015. Mass screening of newborn blood samples was done via TMS/GCMS/Enzyme assay/HPLC/ELISA technique. The blood and urine samples were used for analysis. The samples have been collected from 150 locations through various hospitals across India. Samples obtained were categorised zone wise (east, west, north, south zones of India). For analysis of blood, samples were collected by heel prick method.

Results

In the present study, 2.9% prevalence (of the total 70,590 samples analysed, 2053 cases were found positive) of IEM was observed. Of these positive cases, 13% (279 of 2053 positive cases) cases belonged to eastern zone, 24% (493 of 2053 positive cases) were from northern zone, 38% (793 of 2053 positive cases) were from southern zone and 23% (488 of 2053 positive cases) were from western zone. Among these, the highest prevalent disorder was found to be G6PD deficiency, with 1.3% (923 positive of 70,590) cases reported followed by haemoglobinopathies, 0.5% (360 positive of 70,590) and congenital hyperplasia with 0.34% (239 positive of 70,590) cases of the total newborns, screened.

Conclusion

The newborn screening is expanding its wings throughout the world. The outcome of present data offers a unique opportunity to explore the birth prevalence of inborn metabolic disorders in the current population. Understanding the birth prevalence of these disorders in India from its various zones will definitely improve the short term and long term medical needs faced by affected communities.

Introduction

Inborn errors of metabolism disorders are a complex and heterogeneous group of disorders due to enzymatic defect in single pathway of intermediary metabolism. Certain pathological alterations in normal catabolic path of amino acids, carbohydrates, lipids or biogenic amine often cause abnormal excretion pattern of organic metabolites. These metabolites are normally absent or present in very small concentration [1,2]. The inborn metabolic disorders currently in human beings exceed more than 500 types and of these 100 alone are the disorders of the amino acid metabolism [3]. Being an important cause of morbidity and mortality in clinical practice and any delay in the diagnosis and treatment of these disorders leads to a variety of symptoms including moderate to severe neuropsychological manifestations in the form of mental retardation, seizures, death etc., [4]. Neonatal disorders presently are the major cause of perinatal and neonatal mortality with 9.2% cases alone in urban areas of India [5]. The newborn screening is a technique in our hands to investigate congenital genetic and metabolic disorders in order to prevent the mortality and disabilities associated with these disorders. It is a study meant to screen infants shortly after birth for a list of conditions that are treatable. Symptoms of these disorders are not clinically evident in the newborn period. Some of the conditions included in newborn screening programs are only detectable after irreversible damage has been done. But in many of the cases sudden death is the first manifestation of the disease [6]. Therefore, in present study, mass screening of the blood samples of newborns was done via TMS/GCMS/HPLC/Enzyme assay technique [7,8]. The blood samples for analysis were collected by heel prick method. Both blood and urine (freshly voided urine) samples were collected on filter paper.

Materials and Methods

A cross-sectional, population based prospective study was conducted at PreventiNe Life Care Laboratories. Study was conducted for a period of three years from October 2012 to November 2015. A total of 70,590 neonatal blood and urine samples were analysed for IEM. The samples have been collected from 150 locations through various hospitals across India. These neonates were already enrolled for the cord blood and cord tissue banking and newborn screening was an additional test offered to parents as routine screening to rule out IEM. The neonates belonged to various racial and ethnic groups of India. Samples obtained were categorised zone wise (east, west, north, south zones of India) and processed at Central Laboratory at Navi Mumbai, India. The blood samples for analysis were collected by heel prick method [7]. A pinprick puncture in one heel of the newborn was done and blood was soaked into pre-printed collection cards or Guthrie cards. Urine samples were also collected on filter paper by soaking freshly voided urine. Blood and urine samples were collected in all the cases. Tests done on blood samples were for beta thalassaemia, sickle cell anaemia (HbSS), sickle cell disease (HbS/C), variant haemoglobinopathies (C,D,H barts band), including HbE, congenital hypothyroidism, congenital hyperplasia. Rest of the tests were performed using urine samples. Samples were analysed for 119 disorders including amino acid disorders, fatty acid disorders, organic acid disorders, carbohydrate disorders, peroxisomal disorders and various other disorders using Tandem Mass Spectrometry (TMS), Gas Chromatography-Mass Spectrometry (GC-MS), High Performance Liquid Chromatography (HPLC), Enzyme Assay and Enzyme linked Immunosorbant Assay (ELISA) method [Table/Fig-1,2] [7,8]. Written informed consent from parents was taken before collection and analysis of the samples. Ethical clearance was obtained from ethical clearance committee of Santosh Medical College and Hospital, Ghaziabad, Uttar Pradesh, India. For sample collection, baby was prepared to have 3-4 milk feeds. As stress of birth may change various values especially the thyroid profile, collection of samples for IEM screening during initial 24 hours was avoided. Infants on antibiotics, premature babies or babies on blood transfusion were excluded from the study.

Test done on blood and urine samples.

Test Done on Blood Samples
Haemoglobinopathies
S. No. 1BetaThalassaemia
2Sickle Cell Anaemia (HB SS)
3Sickle Cell Disease (Hb S/ C)
4Variant Haemoglobinopathies(C, D, H, bart band), including HbE
Endocrinology
5Congenital Hypothyroidism
6Congenital adrenal Hyperplasia
Other Genetic Disorders
7Cystic Fibrosis
8G6PD Deficiency
Test Done on Urine Samples
Amino acid disorders
9Phenyl ketonuria
10Defect in Biopterin Cofactor Biosynthesis
11Defects in Biopterin Cofactor Regeneration
12GTP Cyclohydrolase (GTPCH) Deficiency
13Dihydropteridine Reductase Deficiency
14Benign Hyperphenylalaninaemia (H-PHE)
15Tyrosinaemia Type I
16Tyrosinaemia Type II
17Tyrosinaemia Type III
18Trasient Tyrosinaemia in Infancy
19Tyrosinaemia caused by liver dysfunctions
20Maple Syrup Urine Disease (MSUD)
21Carbamoyl Phosphate Synthetase-1 Deficiency
22Ornithine Transcarbomylase (OTC) Deficiency
23Citrullinaemia
24Citrullinaemia Type II
25Argininosuccinic aciduria
26Argininaemia
27Hypermethioninaemia
28Homocysteinuria
29Alkaptonuria
30Tryptophanuria with dwarform
31Xanthurenic Aciduria
32Valinaemia
33Hyperleucinaemia
34Dihydroptoyl Dehydrogenase deficiency
353-Hydroxylbutyryl CoA Deacylase Deficiency
36Histidinuria
37Hurtnup Disease
38Lysinuric Protein Intolerance
39Famillial Renal Iminoglycinuria
40Iminoglycinuria
412-Ketoadipic aciduria
42Sacchropenuria
43Hydroxylysinuria
44Cystathionuria
45Hyperprolinaemia
46Hyperprolinaemia Type II
47Hyperhydroxyprolinaemia
485-Oxoprolinuria
50Hypersarcosinaemia
51Imidazole aminoaciduria
52Formiminoglutamic aciduria
53Serum carnosinase deficiency
54Glutathionuria
55Hyperpipecolatemia
563-Aminobutyric aciduria
57Histidinaemia
Organic acid Disorders
58Propionic acidemia
59Multiple carboxylase Deficiency
60Methyl Malonic Acidemia
61Methyl Malonyl CoA Mutase Deficiency
62Methyl Malonic Aciduria
63Malonic Acidemia
64Biobutyryl CoA Dehydrogenase Deficiency
65MethylButyryl CoA Dehydrogenase Deficiency
66Methyl Malonic Saemialdehyde Dehydrogenase Deficiency
67B-Ketothiolase Deficiency
68Isovaleric aciedmia
693-MethylcrotonylCoA Carboxylase Deficiency
703-Methyl Glutaconic aciduria
713-Hydroxy 3-methyl Glutaric Aciduria
72Glutaric aciduria Type-ll
73Glutaric aciduria Type-l
74Mevalonic Acidemia
753-Methyl 3-Hydroxy Butyric Aciduria
764-Hydroxybutyric aciduria
Carbohydrate Disorders
77Galactosaemia
78Galactokinase Deficiency
79Galactose Epimerase Deficiency
80Transient Galactosaemia
81Fructosuria
82D-Glyceric Aciduria
83Fructose 1, 6 Diphosphatase Deficiency
84Endogenous Sucrosuria
85Lactose Intolerance
Fatty Acid Oxidation disorders
86Short Chain CoA Dehydrogenase deficiency(SCAD)
87Medium Chain CoA Dehydrogenase Deficiency(MCAD)
88Long Chain CoA Dehydrogenase Deficiency (LCAD)
89Very Long Chain CoA Dehydrogenase Deficiency (VLCAD)
90Short/Medium Chain 3-Hydroxy CoA Dehydrogenase Deficiency
91Long Chain 3-Hydroxy CoA Dehydrogenase Deficiency
92Mitochondrial Trifunctional Protein Deficiency
93Carnitine Transport Defect
94Multiple CoA Dehydrogensae Deficiency
95Medium Chain Ketoacyl CoA Dehydrogenase Deficiency
Peroxisomal Disorders
96Zellweger Syndrome
97Neonal Adenoleucodystrophy
98Infantile Refsums Disease
99Zellweger Like Syndrome
100Primary Hyperoxaluria
Disorders of Purine Pyrimidine Metabolism
101Adinosine Deaminase Deficiency
102Lesch Nyhan Syndrome
103Partial Deficiency ofHypoxanthine Adenine Phosphoribosyl Transferase
104Adenine Phosphoribosyl Transferase Deficiency
105Xanthinuria
106Orotic Aciduria
107Thymine uraciluria
108Dihydropyriminidase Deficiency
109Hyperuric Acidemia
Lactic Acidemia, Hyperpyruvic Acidemia
110Pyruvate Dehydrogenase Deficiency
111Pyruvate Dehydrogenase Phosphatase Deficiency
112Pyruvate carboxylase deficiency
113Pyruvate decarboxylase deficiency
114Leigh Syndrome
Other IEM
115Biotinidase Deficiency
116Canavan Deficiency
117Fumerate Hydrolase Deficiency
118Hyperornithinaemia-Hyperammonaemia-Hyperhomocitrullinaemia (HHH) Syndrome
Miscellaneous genetic condition
119Neuroblastoma

Test done on blood and urine samples.

TechnologiesEastNorthSouthWestNumber of cases
Enzyme linked immunosorbant assayn=45n=90n=233n=61n=429
Congenital adrenal hyperplasia17355313118
Congenital hypothyroidism215013037238
Congenital hypothyroidism and beta-thalassaemia11
Cystic fibrosis74491171
Liver disease or hyperalimentation and/or ketoacidosis11
Enzyme assayn=165n=212n=340n=254n=971
Biotinidase deficiency12914641
G6PD deficiency153201321247922
Galactosaemia235
Hyperphenylalaninaemia11
Phenylketonuria112
Gas chromatography mass spectrometryn=6n=75n=53n=49n=183
2-Hydroxyglutaric aciduria22
3-Methylcrotonyl CoA carboxylase deficiency11
3-Methylglutaconic aciduria11
4-Hydroxybutyric aciduria11
Alkaptonuria12126
Beta-keto thiolase deficiency224
Biotinidase deficiency or multiple carboxylase deficiency11
Canavan disease11
Ethyl malonic aciduria11
Galactosaemia11114
Glutaric aciduria11
Glutaric aciduria Type I135624
Glutaric aciduria Type II11114
Hyperglycinuria (nonketotic)22
Hyperornithinaemia (with Gyrate Atrophy)11
Hypersarcosinaemia11
Isovaleric acidemia213
Lactic aciduria11
Lactic aciduria (primary)11
Lactose intoelrance11
Maple syrup urine disease123511
Medium chain acyl CoA dehedrogenase deficiency11
Medium chain acyl CoA dehedrogenase deficiency or 2-Hydroxyglutaric aciduria11
Methyl malonic acidemia222121349
Mitochondrial disorder64717
Mitochondrial disorder (or) primary lactic acidemia11
Multiple acyl dehydrogenase deficiency11
Multiple carboxylase deficiency11
N-acetylglutamate synthase deficiency11
Orotic aciduria11
Phenylketonuria224
Propionic acidemia77418
Pyroglutamic aciduria11
Pyruvate dehydrogenase (E1) deficiency11
Succinate saemialdehyde dehydrogenase deficiency213
Thymine uraciluria22
Tyrosinaemia213
Urea cycle disorder3126
High performance Liquid chromatographyn=58n=62n=139n=101n=360
Haemoglobinopathies5862139101360
Tandem mass spectromretryn=5n=54n=28n=23n=110
3-Hydroxy-3-Methylglutaryl-CoA lyase deficiency HMG11
3-Methylcrotonyl CoA carboxylase deficiency11
3-Methylcrotonyl CoA carboxylase deficiency or mitochondrial acetoacetyl-CoA thiolase deficiency11
Argininaemia22
Argininosuccinic acidemia11
Benign hyperphenylalaninaemia11
Benign hyperphenylalninaemia (or) biopterin cofactor deficiency11
Beta-keto thiolase deficiency224
Biotinidase deficiency or multiple carboxylase deficiency11
Biotinidase deficiency or multiple carboxylase deficiency or 3-Methylcrotonyl CoA carboxylase deficiency11
Carnitine acylcarnitine translocase deficiency11
Carnitine uptake defect213
Carnitine uptake defect or carnitine palmitoyl transferase deficiency Type II (CPT-II)11
Carnitine uptake defect or primary carnitine deficiency123
Citrullinaemia33
Citrullinaemia or arginosuccinic acidemia11
Citrullinaemia Type I11
Citrullinaemia Type I or citrullinaemia Type II or argininosuccinic academia11
Classical hyperphenylalaninaemia or biopterin cofactor deficiency123
Fatty acid oxidation disorder11
Glutaric aciduria Type I73212
Glutaric aciduria Type I or mitochondrial disorder11
Glutaric aciduria Type II33
Homocystinuria and/or hypermethioninaemia11
Hyperalimentation11
Hyperalimentation (or) liver disease22
Hypermethioninaemia or liver disease11
Isobutyryl-CoA dehydrogenase deficiency or short-chain Acyl-CoA dehydrogenase deficiency11
Isovaleric acidemia213
Isovaleric acidemia or 2-Methylbutyryl-CoA dehydrogenase deficiency11
Ketoacidosis11
Maple syrup urine disease111315
Maple syrup urine disease or propionic acidemia11
Medium chain acyl CoA dehedrogenase deficiency or medium chain triglyceride Oil11
Methyl malonic acidemia (MMA) (or) propionic aciduria24410
Methylmalonyl-CoA mutase deficiency (or) propionic acidemia22
Mitochondrial disorder11
Mitochondrial disorder (or) hyperalaninaemia11
Neonatal carnitine palmitoyl transferase deficiency Type I11
Phenylketonuria (or) biopterin cofactor deficiency11
Phenylketonuria (PKU)11
Primary carnitine deficiency112
Propionic acidemia (PA)2158
Short chain hydroxy acyl-CoA dehydrogenase deficiency22
Tyrosinaemia I/II/III/transient11
Tyrosinaemia Type I11
Urea cycle disorder22
Very long chain acyl-CoA dehydrogenase deficiency11
Grand total2794937934882053

Dried Blood Sample (DBS) Analysis on Tandem Mass Spectrometry

The DBS samples were analysed for amino acid and acyl carnitine profile on the system LCMS-MS 8030, Triple-Quadruple Mass Spectrometer equipped with ESI probe (Shimadzu, Japan). DBS samples were processed according to the method stated in Chromsystems reagent kit [9]. With the every batch of patients being tested, a positive and negative control sample was made and analysed. The data analysis was performed on Neonatal Software version 3.2, and the markers were expressed as μmol/L based on its ratio with stable-isotope deuterium-labeled isomer (e.g., Leucine/deuterium-Leucine). Reference values for amino acid and acyl carnitine profiles have been calculated from the DBS concentrations measured in healthy newborns and early infancy.

Urine Analysis by GCMS

For urine filter paper sample analysis, T. Kuhara’s method was followed [10]. Samples were extracted with water and pretreated with urease at 37°C to remove urea followed by deproteinisation with ethanol containing Heptadecanoic acid as internal standard. Samples were then vacuum dried and residues were derivatised by adding N, O,-bistrimethylsilyl) trifluroacetamide (BSTFA) and Trimethylchlorosilane (TMCS). Further, 1 μL Aliquots of derivatised samples were injected into Shimadzu QP-2010 Plus GC/MS using auto sampler in split mode. Analysis of metabolites was conducted chromatographically, using trimethylsilyl derivatised compounds. The data analysed with computer-assisted program and National Institute of Standards and Technology (NIST) library.

Enzyme Linked Immunosorbant Assay

An assay based on sandwich Enzyme Linked Immunoassay (EIA), using peroxidise labelled anti TSH monoclonal antibody in a microwell with coating of another anti TSH monoclonal antibody, was used for diagnosis of congenital hypothyroidism. For microplate neonatal TSH estimation, 1/8 disc was punched out from the blood collection card. Intensity of colour in the microwell was proportional to TSH concentration [11].

High Performance Liquid Chromatography

For Amino acid analysis, Thin Layer Chromatography is used as a preliminary screening technique using Butanol, Acetic acid, Water and staining with ninhydrin. Confirmation of screen positive cases was carried out by reverse-phase HPLC following the pre-column derivatisation with Phenyl isothiocyanate (PITC) [11,12].

Statistical Analysis

All the obtained data were calculated and represented by using Microsoft excel 2007.

Results

With 2.9% prevalence of IEM, out of total 70,590 cases of neonates screened, 2053 cases (including both male and female neonates) were found positive. Neonates were screened for total 119 disorders [Table/Fig-1]. The most prevalent disorder was found to be G6PD deficiency with 923 (1.3% of total screened 70,590 cases) cases positive with 44% prevalence (923 of 2053 positive cases) followed by 360 (0.5% of total screened 70,590 cases) cases with 17.5% prevalence (360 of 2053 positive cases) of haemoglobinopathies and the number of congenital hyperplasia and congenital adrenal hyperplasia were 239 (0.34% of total screened 70,590 cases) and 118 (0.16% of total screened 70,590 cases) of the total cases screened for NBS with prevalence of 11.6% (239 of 2053 total positive) and 5.7% (118 of 2053 positive) respectively. Various amino acid disorders screened were citrullinaemia-l, homocysteinuria, hypermethioninaemia, Maple Syrup Urine Disease (MSUD), tyrosinaemia Type l, ll, lll, phenylalaninaemia etc., and are clearly mentioned in [Table/Fig-1]. Number of all positive cases are shown in [Table/Fig-2]. Highest number of cases was of MSUD (26) with 1.2% prevalence (26 out of 2053) followed by phenylketonuria and alkaptonuria with 0.3% and 0.2 % prevalence (7 and 6 of 2053 positive cases). Among fatty acid disorders, highest number of cases (7) of Carnitine Uptake Defects (CUD) was found with 0.3% prevalence (7 out of 2053 positive). One case each of Medium Chain Acyl-Coa Dehydrogenase Deficiency (MCAD), carnitine palmitoyl transferase deficiency Type-l and 2 cases of Short Chain Hydroxyl-Acylcoa Dehydrogenase Deficiency (SCHAD) were observed with 0.04% (1 of 2053 positive) and 0.09 % (2 out of 2053 positive) prevalence respectively [Table/Fig-2]. Rest of the disorders and number of positive cases are mentioned in [Table/Fig-1,2]. Other disorders with significant number of cases were glucose 6 phosphate dehydrogenase deficiency with 44% prevalence (923 of 2053 positive), cystic fibrosis with 3.4% prevalence (71 of 2053 positive cases) and biotinidase deficiency with 1.9% prevalence (41 of 2053 positive) and others disorders are shown in [Table/Fig-2]. Zone wise distribution of the cases are clearly mentioned in [Table/Fig-1,2]. Also, clear account of use of techniques done, for detection of the diseases are presented in [Table/Fig-1,2].

Discussion

There was significant number of positive cases seen in series of neonatal tests. Similar data in the local population is practically rare for comparison though very few such studies have been conducted and reported in other states. In current scenario there is basic and stern requirement for a screening program, to avail the epidemiological data regarding disease burden. In India, the birth rate is 21.76 births/1,000 population [13]. Delhi alone has nearly 900 births, reported every day and out of these one or two babies are born with a metabolic defect [14]. However, the diagnosis is ignored due to lack of awareness and easily available techniques. Also, because present health policies are more concerned towards prevention of mortality and that figure has of course rectified but there has been a simultaneous hike in number of cases of disabilities too. In this newborn screening study carried out among 70,590 neonates, G6PD disorder was found to be most prevalent with 1.3% (923 cases of 70590 screened) of all the cases screened and with 44% prevalence (923 of total 2053 positive cases). The next most common disorder was haemoglobinopathies with 0.5% (360 cases) and with 17.5% prevalence (360 cases of 2053 positive cases) followed by 0.34% (239 cases of 70590 screened) cases of Congenital Adrenal Hyperplasia (CAH) with 11.6% (239 of 2053 positive cases) prevalence and 0.16% (118 cases of 70590 screened) of Congenital Hypothyroidism (CH) with 5.7% (118 cases of 2053 positive cases) prevalence. In one of the major study conducted among 125 thousand neonates, have reported homocysteinaemia, hyperglycinaemia, MSUD, phenylketonuria (PKU), congenital hypothyroidism and G6PD deficiency to be the most common disorders with good prevalence [15]. A study done in year 2014 have documented CH, CAH, G6PD, Biotinidase deficiency, galactosaemia and cystic fibrosis as the most prevalent disorders [16]. In a hospital population based study, 2479 neonates were screened for G6PD deficiency, and had a 28.3% incidence in males and 1.05% in female neonates [17]. Considered as most life threatening disorders, haemoglobinopathies are a group of a number of disorders including β-thalassaemia, sickle cell anaemia etc. According to WHO nearly 10,000 babies in India are born every year affected with β-thalassaemia [18]. Tribal community which represents our 8% Indian population, predominantly suffer from sickle cell anaemia [19]. Significant number of cases of haemoglobinopathies was reported in present study. In one more study conducted at AIIMS, CAH was diagnosed in about 38% children presenting with ambiguous genitalia [20]. So outcome of present study are compatible with earlier reports documented. Infact for CH, CAH and glucose-6-phosphate dehydrogenase deficiency, neonatal screening has been proposed to be must in Indian scenario. In one of the study conducted by Gopalkrishnan V et al., done in Lucknow, Uttar Pradesh in 2014, cut-offs for galactosaemia and biotinidase deficiency were 0.32% and 0.16%, respectively while in present study the cut-off values were found to be 0.43% and 1.9% [16]. Cystic fibrosis cases have been reported rare in Indian population with prevalence 1/43,321 to 1/100,323 [19]. In a study conducted at Hyderabad also, have shown maximum prevalence of cystic fibrosis, galactosaemia and biotinidase deficiency beside other disorders including cases of urea cycle disorders [15]. Mitrochondrial disorders were less than 1%. From the analysis of various studies it is apparent that a significant portion of the population is being affected from metabolic disorders. While before it can be recommended to be included in a nationwide screening program, lot many studies are needed to be done. In present study an attempt is also made to understand the geographical distribution of the IEM among newborn, zonal categorisation of the positive cases has been done. Zonal frequency was found with maximum cases found in southern zone with 38.5% (793 cases of 2053 positive) prevalence, northern zone 24.2% (493 cases of 2053 positive) prevalence, west zone 23.7% (488 cases of 2053 positive), and in eastern zone 13.57% (279 cases of 2053 positive) prevalence of IEM in India. Such type of zone wise presentation of NBS data is rarely reported in the literature in India. In the last few years India has immensely progressed in the field of medical science and technology. Laboratory advancement especially in mass spectrometry has facilitated so much easier screening of newborns for many IEM. This is the need of time for all of us to be aware of the fact that early detection, appropriate investigation and treatment can prevent the morbidity and mortality in neonates. A number of such studies are also needed to be done to determine actual prevalence of disorders in different parts of India. Though, in Asia Pacific region, there are clear evidences of growth of newborn screening, well reported in the literature. Newborn screening through blood spot began in New Zealand and Australia in the year 1960, followed by Japan and then in Singapore through cord blood screening for G6PD. Screening for congenital hypothyroidism as an additional screening started in 1980 followed by development of new programmes started in countries like Taiwan, Hong Kong, China, India, and Malaysia [22]. During 1990’s various new programmes developed based on previous experience especially in Korea, Thailand and Philippines with rapid growth. In the year 2000’s countries including Indonesia, Magnolia, Sri Lanka, Myanmar and Pakistan with limited funding from the International Atomic Energy Agency, started a screening programme for congenital hypothyroidism [21]. Recently Palau and Philippine jointly started NBS programme while there is very less information available on newborn screening activities in Nepal, Cambodia, Laos and the other Pacific Island nations [21,22]. According to the current data, around 131 million babies are born every year across the globe and approximately 7.9 million are born with IEM [22]. Nearly half of the births and defects occur in Asia Pacific region and almost 80% of these occur in China, Indonesia, Bangladesh, India, and Pakistan [23]. Japan has expanded the NBS program through funding support for IEM of aminoacids, organic acids, fatty acid metabolism in the year 2012 while in other Asian countries patients generally pay for these cost effective testing [24]. Taiwan, Japan and Korea have recently reported new born screening of Lysosomal disorders and Pompe disease [25-27]. From the limited data available of NBS in the Asian countries, an apparent high incidence of CAH has also been reported [28]. In present study also the 3.1% prevalence has been observed. As far as NBS initiation and implementation program in developing countries, especially South-East Asian is concerned, it is running at very slow pace and a very challenging job here. Infact in most of the countries, NBS is not mandatory and has not yet been incorporated into the public healthcare system [28,29]. Limited funding, manpower shortages, inadequate support services, low public awareness are the main challenges which nations have to face. Though Laws requiring new born screening or its offering now well established in some of the countries and significant efforts are being made to include NBS as national health insurance maternity benefits packages. Asia Pacific region is reported have half of the births in the world. So in order to maintain the health status of the children, proper implementation and expansion of NBS is very much required [30].

Limitation

We were unable to produce separate male and female data of the diseases. Also, we have not discussed the conditions where two or more diseases may possibly be present in the same patient.

Conclusion

NBS has been established as important tool to detect inborn errors of metabolism. In order to curb the incidence of congenital anomalies, World Health Organisation has recommended for new born screening. However, current state of NBS is not very good in Asian countries. The main challenges in establishing this program have been the lack of funds, less awareness in public, inadequate manpower and support services. Early diagnosis may save a number of children from getting disabled. In fact presymptomatic evaluation of these conditions through NBS will definitely minimise the irreversible, life threatening changes and will thereby improve the treatment regimen. A significant number of positive cases were found in present screening of new born babies, which apparently shows that IEM disorders are quite prevalent in Indian population. The present study put forward many facts about demographic prevalence in India but many such studies are required to be done in the direction so as to establish the actual burden of IEM, their various types and strategies to cop up with these situations.

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