الفهرس 
Lung developmentOnly 14 pages are availabe for public view
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Abstract
Respiratory Distress Syndrome (RDS) previously called hyaline membrane disease is a life threatening disease in premature neonates.
RDS is due to a deficiency and immaturity of alveolar surfactant along with structural immaturity of the lung and it is mainly, but not exclusively, confined to preterm babies.
Natural course begins at or shortly after birth in premature infants and increases in severity over the first 2 days of life. If left untreated, death can occur from progressive hypoxia and respiratory failure.
Renin–angiotensin system (RAS) controls the blood pressure, liquid, and electrolyte equilibrium, angiotensin-converting enzyme (ACE) is a membrane-bound exopeptidase located in many types of cells‟ membrane
The vascular structure of the lung is one of the major regions in presenting ACE. ACE-encoding gene in humans is located in 17q23, which is 21 kb in length and includes 26 exons and 25 introns
The most frequent polymorphism of ACE gene is the existence or absence of the intron 16 (287-bp alu repeat sequence), known as the insertion/deletion (I/D)-type polymorphism.
The existence (insertion [I]) or the absence (deletion [D]) of intron 16 can result in three different genotypes: D/D, I/I homozygotes, and I/D heterozygote.
This insertion in ACE gene decreases ACE expression, and thus D/D homozygotes have 65% and 31% more ACE activity than I/I homozygotes and I/D heterozygotes, respectively
Evaluation of the ACE I/D gene polymorphism in premature infants with and without RD within the first 24 hours of life.
We found that significant association exists between the development of RDS in patient group and the ACE gene D/I genotype.
The presence of ACE gene I variant is associated with increased incidence of RDS.
Summary
75
In a prospective study conducted in the Pediatric Department of Menoufia University and Berkt Elsabaa Hospital,we examined 100 premature neonates were divided into two equal groups as follows:
group 1 (Patient group):
Included 50 preterm neonates; 31 male and 19 female born between 30 and 36 weeks gestational age with mean gestational age 31.4 weeks, diagnosed according to the presence of typical clinical and radiological criteria of RDS in preterm infants.
group 2 (Control group):
Included 50 preterm neonates ; 28 males and 22 females born between 34 and 36 weeks gestational age with mean gestational age 34.96 weeks with no signs of respiratory distress .
All patients were subjected to the following after taking informed consent:
- Full Detailed history, complete clinical examination, assesment of Respiratory distress grades
- Laboratory Investigations: Compete blood count (CBC), C-reactive protein (CRP), and Arterial blood gases (ABG). Plain chest x-ray were done and Echocardiography (ECHO) to exclude PDA.
- Molecular Study of ACE Gene Polymorphism which was made by lab investigation (RFLP) in our genetics and endocrinology unit lab in the pediatric department, Menoufia university including:
Deoxyribonucleic acid extraction.
Polymerase chain reaction (PCR)
Gel electrophpresis
This study revealed that:
By gene testing, D/D genotype was found in 13 patients in patients group (26%) and 24 babies in control group (48%).
D/I genotype was found in 20 patients in patients group (40%) and 25 babies in control group (50%). I/I genotype was found in 17 patients in patients group (34%) and one baby in control group (2%).
Summary
76
ACE gene polymorphism D/I was frequent in patient group and control group, D/D genotype was frequent in control group and I/I genotype was higher in neonates with RDS than in controls (p.value < 0.001).
By counting D alleles among members of both groups, it is found 46 times in patient group (46%) and 73 times in control group (73%).and
I alleles was found 54 times in patient group (54%) and 27 times in control group (27%).
These findings may suggest that the I allele of the ACE gene increased the risk for RD, and the D allele and D/D genotype could be protective against RD in neonates.
D allele was significantly higher in control group and I allele was significantly higher in patient group (p .value < 0.001).
Respiratory distress grades, duration of O2 support and duration of admission increase the severity of RDS in patient group ACE gene D/I genotype.
Maternal age, premature rupture of membrane and antenatal steroid administration are considered as significant predictive risk factors for ACE gene D/I polymorphism plays arole in occurrence of RDS.
Low gestational age and low birth weight increase incidince of RDS.