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Does elevated hemoglobin F modulate the phenotype in Hb SD-Los Angeles?

Adekunle Adekile1, Ali Mullah-Ali, Najwa Ali Akar

  • 1Department of Pediatrics, Kuwait University, Kuwait, Kuwait. adekile@hsc.edu.kw

Acta Haematologica
|January 30, 2010
PubMed

Insights

Compound heterozygotes with Hemoglobin (Hb) SD-Los Angeles and elevated Hb F experience severe symptoms. Unlike Hb SS patients, elevated Hb F does not appear to improve the clinical outcome in Hb SD-Los Angeles.

Area of Science:

  • Hematology
  • Genetics
  • Pediatrics

Background:

  • Hemoglobin (Hb) SD-Los Angeles compound heterozygotes typically present with severe clinical manifestations.
  • The impact of elevated fetal hemoglobin (Hb F) on the clinical phenotype of Hb SD-Los Angeles has not been previously documented.

Observation:

  • This study details 5 Kuwaiti children diagnosed with Hb SD-Los Angeles and Hb F levels exceeding 20%.
  • These children exhibited early-onset sickling-related symptoms (by age 2) and were monitored for 3-15 years.
  • All participants experienced severe clinical courses.

Findings:

  • The observed severe clinical course included splenic sequestration crises, acute chest syndrome, vaso-occlusive crises, osteomyelitis, and avascular necrosis of the femoral head.
  • This contrasts sharply with the typically milder presentation observed in Kuwaiti patients with Hb SS and elevated Hb F.
  • Elevated Hb F levels did not ameliorate the clinical phenotype in these Hb SD-Los Angeles patients.

Implications:

  • Fetal hemoglobin (Hb F) may not offer a protective effect against severe disease in Hemoglobin (Hb) SD-Los Angeles.
  • Further research is needed to elucidate the mechanisms underlying the lack of Hb F amelioration in Hb SD-Los Angeles.
  • Understanding these mechanisms could inform future therapeutic strategies for sickle cell disease variants.

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