Serum beta-hexosaminidases in pregnancy.

Area of Science:

• Biochemistry
• Genetics
• Clinical Chemistry

Background:

• Serum contains multiple hexosaminidase (HEX) forms, including HEX A, HEX B, and an intermediate form (HEX I).
• HEX I levels increase during pregnancy, potentially complicating carrier detection for genetic disorders.
• Tay-Sachs and Sandhoff diseases are inherited conditions caused by HEX deficiencies.

Purpose of the Study:

• To investigate the utility of serum hexosaminidase analysis for carrier detection of Tay-Sachs and Sandhoff diseases, particularly during pregnancy.
• To differentiate between normal HEX profiles and those of carriers, considering the impact of pregnancy.

Main Methods:

• DEAE-cellulose chromatography was employed to separate serum HEX A, HEX I, and HEX B.
• Activity ratios of HEX A/B were measured in normal individuals, pregnant individuals, and carriers of Tay-Sachs and Sandhoff diseases.
• Heat lability of HEX B and HEX I forms was assessed in carrier sera.

Main Results:

• DEAE-cellulose chromatography effectively separated HEX A, I, and B.
• Normal HEX A/B ratios were significantly higher than those in Tay-Sachs heterozygotes.
• In Sandhoff heterozygotes, HEX B and HEX I forms showed 50% heat lability.
• Pregnancy-induced changes in HEX levels did not preclude reliable carrier identification.

Conclusions:

• Serum hexosaminidase analysis, using DEAE-cellulose chromatography, is a reliable method for identifying carriers of Tay-Sachs and Sandhoff diseases.
• Serum HEX analysis remains effective for carrier detection even during pregnancy.
• Heat lability of specific HEX forms can aid in differentiating carrier types.