Prenatal genetic testing, counseling and follow-up of 33 Egyptian pregnant females with history of mucopolysaccharidoses

Abstract

Background: Mucopolysaccharidoses (MPS) are autosomal recessive disorders characterized by deficiency of lysosomal enzymes which break down the glycosaminoglycans (GAGs) which results in widespread intra and extra-cellular accumulations of GAGs. Early initiation of treatment, before the onset of irreversible tissue damage, clearly provides a favorable disease outcome. Early detection might be afforded by analysis of amniotic fluid. Aim: To report our experience of prenatal diagnosis of MPS over 14-year period for cases referred from medical centers throughout Egypt. Also to report the benefit of prenatal genetic testing in cases accompanied with genetic disorders. Materials and methods: The present study included 33 pregnant women at risk of having a fetus with MPS. Of these cases, 3 women had more than one pregnancy evaluated. All cases had a detailed genetic ultrasound examination and a maternal serum alpha-fetoprotein (MSAFP) evaluation during the second trimester of pregnancy. Thirty-eight amniocentesis procedures were performed during the study for 2 dimensional electrophoresis (2-DEP) of GAGs. Results: Positive consanguinity was present in near 70% (23/33) of the couples. Detailed genetic ultrasound examination revealed a case with anencephaly and another one with a twin pregnancy. One case had a MSAFP of 3.6 multiple of the normal median (open neural tube defect). Another 2 cases had a risk of having Down syndrome. Results of the 2-DEP of GAGs in amniotic fluid revealed 36.8% (14/33) affected fetuses. During the final counseling setting of the 14 cases with abnormal results, 43% (6/14) elected to continue their pregnancy while 57% (8/14) elected termination. Conclusion: Early prenatal screening and diagnosis, through a systematic multidisciplinary approach, to all cases of mucopolysaccharidoses are recommended, to improve the quality of life and to avoid the presence of other associated fetal developmental malformations.

Keywords

• Mucopolysaccharidosis
• Alpha-fetoprotein
• Amniotic fluid
• Glycosaminoglycans