Methodology

Results

Amino Acid Levels in Newborns

A Pilot Study on an Expanded Newborn Screening Program in Palestine

Samir Khatib , Amer AyyadMedical School / Al-Quds University

Introduction

Newborn screening is a universal health program which is useful in the early

detection of serious metabolic and genetic diseases in newborns before

symptoms begin to appear. Until this day newborns in Palestine are being

screened for phenylketonuria and congenital hypothyroidism only. However,

a number of other metabolic diseases have been recognized amongst the

population, including amino acid and urea cycle disorders. Therefore, the

study was conducted in an effort investigate the possibility of finding such

cases in newborns throughout the West Bank of Palestine. The study was

conducted in collaboration with the Palestinian Ministry of Health through the

collection of samples, and the Human Genetics Department at Liege

University in Belgium by analysing the samples.

Study objectives

*To assess the need for expanding the existing newborn screening program in Palestine.

*To investigate the relationship between some demographic variables such as

gender, kinship, district, weight and amino acids levels.

*To determine the reference ranges for a number of amino acids and urea cycle

intermediates in Palestinian newborns.

A cross-sectional observational study design was done. The study covered all

12 districts of the West Bank in Palestine during the period between January

2012 and January 2013 . A pilot study was done before the actual study took

place. Convenience sampling was used to recognize the study participants of

newborns. Blood samples were collected on special blood collection cards.

Information regarding weight, date of birth, sex , district, and kinship of parents

was taken. Number of samples was 4240 and informed consent was taken

from each parent participant. Analysis of amino acids and urea cycle

intermediates was done using tandem mass spectrometry (MS/MS) .

Introduction and Study objectives

Amino Acids Amino Acids Lower limit Lower limit (µmol/L)(µmol/L)

Upper limit Upper limit (µmol/L)(µmol/L)

MeanMean Std. DeviationStd. Deviation

Phenyalanine 34.9 79.7 53.31 11.24

Tyrosine 60.2 201.3 114.99 35.54

Methionine 11.7 27.9 18.52 4.19

Leucine-Isoleucine 127.0 336.0 208.95 52.72

Valine 82.2 206.3 131.46 30.96

Citrulline 9.3 26.2 15.78 4.30

Argininosuccinate 0.2 0.8 0.43 0.16

Arginine 4.8 28.5 12.95 6.19

Asparagine-Ornithine 57.5 244.9 121.52 46.86

Reference ranges of amino acids based on Non parametric percentile method(CLSI C28-A3)

Amino Acid Amino Acid NormalNormal AbnormalAbnormal TotalTotal

Count Row N % Count Row N % Count Row N % Phenylalanine 4105 96.8% 134 3.2% 4239 100%

Tyrosine 4081 96.3% 158 3.7% 4239 100%

Methionine 4076 96.2% 163 3.8% 4239 100%

Leucine-Isoleucine 4068 96.0% 171 4.0% 4239 100%

Valine 4076 96.2% 163 3.8% 4239 100%

Citrulline 4069 96.0% 170 4.0% 4239 100%

Argininosuccinate 4089 96.5% 150 3.5% 4239 100%

Arginine 4069 96.0% 170 4.0% 4239 100%

Asparagine-Ornithine 4076 96.2% 163 3.8% 4239 100%

Conclusions

*Based on our established reference ranges for each analyte the results showed that 22.5% of the tested samples (955) had at least one amino acid

level in the upper 2.5% of the population.

* There is a significant relationship between mean weight and gender.

*There is a significant relationship between mean weight and some amino acids levels.

*Neither gender nor kinship had any effect on the amino acid level, but there is a significant difference between some amino acids mean and gender.

*There is a significant difference between some amino acids levels and districts.

* The study results support further assessment of the need to expand the existing newborn screening program in Palestine.

Contact information

Status of Abnormal Amino Acid Levels in Newborns

Amino Acid GenderN Mean Std. Deviation

Std. Error Mean

P-Value by independent

sample T-TestPhenylalanine Female 2104 53.73 14.43 0.31

.714Male 2135 53.88 12.56 0.27Tyrosine Female 2104 119.11 41.44 0.90

.002Male 2135 115.23 39.39 0.85Methionine Female 2104 18.99 4.82 0.11

.034Male 2135 18.66 5.10 0.11Leucine-Isoleucine Female 2104 211.14 58.29 1.27

.065Male 2135 214.62 64.16 1.39Valine Female 2104 134.31 34.16 0.74

.180Male 2135 132.84 37.28 0.81Citrulline Female 2104 16.39 5.67 0.12

.090Male 2135 16.09 5.88 0.13 Argininosuccinate Female 2104 0.44 0.18 0.00

.302Male 2135 0.45 0.19 0.00 Arginine Female 2104 13.03 7.04 0.15

.000Male 2135 13.83 7.65 0.17 Asparagine-Ornithine Female 2104 124.43 62.77 1.37

.289Male 2135 126.36 55.82 1.21

Relationship between Gender and Mean Amino Acid Levels

Amino Acid Test Mean WeightP-Value by Independent

sample T-Test Phenylalanine Normal 3.23

0.718Abnormal 3.22 Tyrosine Normal 3.23

0.011Abnormal 3.13

Methionine Normal 3.23

0.214Abnormal 3.18 Leucine-Isoleucine Normal 3.24

0.001Abnormal 3.11

Valine Normal 3.23

0.193Abnormal 3.18 Citrulline Normal 3.23

0.52Abnormal 3.21 Argininosuccinate Normal 3.23

0.852Abnormal 3.22 Arginine Normal 3.23

0.367Abnormal 3.26 Asparagine-Ornithine Normal 3.23

0.06Abnormal 3.16

Relationship between Mean Weight and Amino Acid Levels

Relationship between District and Phenylalanine Level

Relationship between District and Citrulline Level

Relationship between District and Arginine Level

Relationship between District and Asparagine-Ornithine

Level

Samir Khatib, Genetics and Metabolic Diseases Center,

Alquds University Medical School, Abu Dis, Jerusalem, Palestine.

skhatib@med.alquds.edu00972-54-6352826. NOTE: The authors disclose

no conflict of interest.