Fetal Hemoglobin H Hydrops Fetalis: Another Three Case Reports

Area of Science:

• Genetics
• Maternal-Fetal Medicine
• Hematology

Background:

• Nondeletional alpha-thalassemia represents a significant genetic risk factor for severe fetal anemia and hydrops fetalis.
• Hemoglobin H (Hb H) disease encompasses a spectrum of alpha-thalassemia mutations, with nondeletional forms posing a particular threat to fetal well-being.

Observation:

• Three cases of hydrops fetalis were identified in pregnancies affected by nondeletional alpha-thalassemia.
• Two cases were attributed to hemoglobin H-Quong Sz disease, and one to homozygous hemoglobin Constant Spring.
• Fetal hydrops manifested in the late second trimester across all reported cases.

Findings:

• Nondeletional alpha-thalassemia, specifically Hb H-Quong Sz disease and homozygous Hb Constant Spring, is a direct cause of hydrops fetalis.
• The onset of hydrops fetalis in these cases occurred during the late second trimester, highlighting a critical window for intervention.

Implications:

• Pregnancies with risk factors for fetal nondeletional Hb H disease require stringent and regular ultrasound surveillance.
• Early prenatal diagnosis, even without intrauterine transfusion capabilities, empowers parents to make informed decisions regarding pregnancy management.