Trisomy 9 mosaicism diagnosed in utero

Area of Science:

• Genetics
• Prenatal Diagnosis
• Fetal Medicine

Background:

• Trisomy 9 mosaicism is a rare chromosomal abnormality.
• Prenatal diagnosis is crucial for managing affected pregnancies.

Observation:

• Three cases of trisomy 9 mosaicism diagnosed via amniocentesis were identified.
• Cases presented with fetal abnormalities, including severe and mild fetal growth restriction (FGR).

Findings:

• Severe FGR was associated with intrauterine fetal demise (IUFD) in two cases.
• Mild FGR with congenital diaphragmatic hernia resulted in live birth with severe developmental delay.
• Fetal growth restriction is a primary prenatal indicator of trisomy 9 mosaicism.

Implications:

• Trisomy 9 mosaicism poses significant risks to fetal development and survival.
• Prenatal identification of FGR is critical for assessing prognosis in trisomy 9 mosaicism.
• Management strategies should consider the potential for IUFD and severe developmental outcomes.