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Low arylsulphatase A activity and choreoathetotic syndrome in three siblings: differentiation of pseudodeficiency

J Kappler1, R W Watts, E Conzelmann

  • 1Institut für Humangenetik der Universität, Bonn, Federal Republic of Germany.

European Journal of Pediatrics
|February 1, 1991
PubMed

Insights

Three siblings with neurological symptoms were found to have a pseudodeficiency genotype, not metachromatic leukodystrophy (MLD). Genetic testing is recommended to confirm MLD diagnoses, especially without sulphatiduria.

Area of Science:

  • Neurogenetics
  • Biochemistry

Background:

  • Metachromatic leukodystrophy (MLD) is a rare genetic disorder.
  • Accurate diagnosis is crucial due to severe implications.

Observation:

  • A family presented with three children exhibiting choreiform movements, dystonic posturing, and dysarthria since childhood.
  • Previous diagnosis suggested an unusual form of MLD.

Findings:

  • Polymerase chain reaction (PCR) analysis revealed a pseudodeficiency genotype (ASAp/ASAp) in all three siblings.
  • No abnormal sulphatiduria was detected.
  • Neurological symptoms and low arylsulphatase A activity were deemed unrelated to MLD in this family.

Implications:

  • The study highlights the importance of genetic testing, such as PCR and allele-specific oligonucleotide probes, for confirming MLD diagnoses.
  • Recommends corroborating MLD diagnosis when sulphatiduria is absent and sural nerve biopsy is inconclusive.
  • Distinguishing pseudodeficiency from actual MLD is critical for appropriate patient management and genetic counseling.

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