Detection of Turner syndrome using high-throughput quantitative genotyping

Area of Science:

• Genetics
• Molecular Biology
• Medical Diagnostics

Background:

• Turner syndrome (TS) is a common genetic condition in females caused by X chromosome abnormalities.
• Delayed diagnosis of TS can lead to missed opportunities for timely evaluation and treatment.
• Some girls with TS may have occult Y chromosome material, complicating diagnosis.

Purpose of the Study:

• To develop a quantitative genotyping method for newborn screening of TS.
• To enable early detection and treatment of TS and related sex chromosome abnormalities.
• To address the need for a reliable screening method to prevent delayed TS recognition.

Main Methods:

• Assembled a panel of informative single nucleotide polymorphism (SNP) markers spanning the X chromosome.
• Designed pyrosequencing assays for quantitative genotyping of sex chromosome abnormalities.
• Utilized zygosity and signal strength analysis to genotype 46,XX, 46,XY, 45,X, and TS mosaics.
• Developed pyrosequencing assays for Y chromosome material detection.

Main Results:

• Four informative SNP markers achieved 100% sensitivity in identifying TS girls (45,X, partial deletions, mosaicism).
• Y chromosomal material was detected with 100% sensitivity in mosaic individuals.
• The quantitative genotyping approach demonstrated high accuracy for TS detection.

Conclusions:

• Quantitative genotyping offers an inexpensive, high-throughput screening method for TS.
• This approach can be applied to screen for other sex chromosome disorders.
• Early detection of TS through newborn screening is feasible and beneficial.