Introduction: Mucopolysaccharidosis type II (MPSII) is an X-linked lysosomal disorder caused by
deficiency of
iduronate -2-
sulfatase (
IDS ). In this study, we proposed a new protocol for
prenatal diagnosis , using
DNA obtained from
amniotic fluid cells that did not attach to the bottom of the
culture flask after the first medium change.
Methods: Four pregnant MPS II carriers were referred to the
Medical Genetics Service of
Hospital de Clinicas de Porto Alegre for a
prenatal diagnosis and identification of the
disease , which were performed by
polymerase chain reaction (
PCR ) amplification,
restriction fragment length polymorphism , and sequencing according to the
mutation previously found in the
family .
Results: The
analysis indicated the absence of
mutation in three fetal materials and the presence of
mutation in one case. Concomitantly,
cytogenetic and biochemical analyses were performed after 12 days of
cell culture , and only one case showed absence of
enzyme activity, confirming the molecular
analysis .
Conclusions: This diagnostic protocol designed to provide more robust results and safer
genetic counseling suggests that
DNA obtained from floating
amniotic fluid cells can be used as a source of fetal material to allow a faster alternative for
prenatal care through molecular
analysis .
Determination of
IDS gene mutation in fetal
amniotic fluid cells together with
IDS enzyme activity testing is a rapid, sensitive and accurate
method for
prenatal diagnosis of MPS II for high-
risk pregnant women .