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Adenosine-deaminase deficiency in a child diagnosed prenatally
Insights
Adenosine deaminase (ADA) deficiency in red blood cells causes severe combined immunodeficiency (SCID). Prenatal diagnosis via amniotic fluid cell analysis allowed for early identification of ADA deficiency in a subsequent pregnancy, confirming the genetic disorder.
Area of Science:
- Immunology
- Genetics
- Biochemistry
Background:
- Severe combined immunodeficiency (SCID) is an inherited disorder affecting immune system function.
- Red-blood-cell adenosine deaminase (RBC-ADA) deficiency is linked to an autosomal recessive form of SCID.
- Previous family history indicated SCID and potential heterozygous status for ADA deficiency.
Purpose of the Study:
- To investigate the potential for prenatal diagnosis of ADA deficiency in a family with a history of SCID.
- To confirm the diagnosis of ADA deficiency in a subsequent pregnancy.
Main Methods:
- Assessed RBC-ADA levels in family members to identify heterozygous carriers.
- Analyzed ADA activity in cultured amniotic fluid cells from a subsequent pregnancy.
- Confirmed diagnosis at birth by measuring ADA activity in the child's red blood cells.
Main Results:
- Family members exhibited RBC-ADA levels consistent with heterozygous ADA deficiency.
- Amniotic fluid cell cultures showed significantly reduced ADA activity (<1.5% of normal).
- The infant was born with absent RBC-ADA activity, confirming prenatal diagnosis.
Conclusions:
- Prenatal diagnosis of ADA deficiency is feasible using amniotic fluid cell analysis.
- Early identification allows for timely management of SCID patients.
- Clinical presentation in the diagnosed child mirrored that of a previously deceased sibling with SCID.
Abstract:
Deficiency of red-blood-cell adenosine deaminase (R.B.C.-A.D.A.) has been reported in a proportion of patients with the autosomal recessive form of severe combined immunodeficiency (S.C.I.D.). In a family in which a child had died with S.C.I.D., R.B.C.-A.D.A. levels in the parents and other members of the family were compatible with a heterozygous state for A.D.A. deficiency. Cultured amniotic-fluid cells obtained from a subsequent pregnancy contained less than 1.5% of A.D.A. activity of normal amniotic cultures. The prenatal diagnosis of A.D.A. deficiency was confirmed at birth by the absence of A.D.A. ACTIVITY IN THE CHILD'S RED-BLOOD-CELLS. Clinical and laboratory findings in this child are similar to those of the sibling who had died with S.C.I.D.