Prenatal diagnosis for adenosine deaminase deficiency

Area of Science:

• Genetics
• Immunology
• Prenatal Diagnostics

Background:

• Severe combined immunodeficiency (SCID) is a group of rare genetic disorders characterized by profound defects in the immune system.
• Adenosine deaminase (ADA) deficiency is a specific genetic cause of SCID, leading to a buildup of toxic metabolites that harm lymphocytes.
• Prenatal diagnosis is crucial for families with a history of genetic disorders to assess fetal health and plan for management.

Observation:

• Amniocentesis was performed in two pregnancies of a mother with a previously diagnosed child with ADA deficient SCID.
• Adenosine deaminase (ADA) levels were assayed in amniotic fluid fibroblasts obtained from both pregnancies.
• Cord blood and fetal tissues were analyzed post-delivery and post-abortion, respectively, to confirm enzyme activity.

Findings:

• The first pregnancy was determined to be normal with detectable ADA levels.
• The second pregnancy was identified as homozygous deficient for ADA, with undetectable enzyme activity.
• Postnatal analysis confirmed normal ADA levels in the healthy infant from the first pregnancy.
• Analysis of the abortus from the second pregnancy revealed undetectable ADA activity in erythrocytes, spleen, liver, and kidney.

Implications:

• Prenatal diagnosis of ADA deficiency via amniocentesis is a reliable and effective procedure.
• Early identification of ADA deficiency allows for potential interventions, such as enzyme replacement therapy or hematopoietic stem cell transplantation.
• This diagnostic capability empowers families to make informed decisions regarding pregnancy management and future reproductive planning.