Prenatal diagnosis of single gene disorders using amniotic fluid as the starting material for PCR.

A rapid and inexpensive method for fetal genetic diagnosis using amniotic fluid (AF) as the starting material was demonstrated in this study. Raw AF was added directly to polymerase chain reaction (PCR) mixtures with HpH buffer (a high pH buffer), without any pre-treatment. Amplified products were detected by gel electrophoresis and then subjected to Sanger sequencing. The AF from four fetuses, each expressing a single gene disorder (achondroplasia, hypochondroplasia, thanatophoric dysplasia, or X-linked hypohidrotic ectodermal dysplasia), were analyzed. DNA fragments of different lengths were efficiently amplified from 8 μl of AF, allowing each of these single gene disorders to be successfully diagnosed. Although the amplification efficiency of the AF-PCR method is comparable to that of the Chelex method, the amount of the AF sample required was considerably lower than that required for the Chelex method (10 ml). This proposed method of diagnosis is more efficient, simpler, and less expensive, and reduces the chance of cross-contamination relative to the Chelex method, which requires purified DNA or other pre-treatment processes. Our method offers a promising tool that can be used for the diagnosis of various gene disorders in fetuses.