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Journal of Inherited Metabolic Disease

, Volume 28, Issue 2, pp 203–227 | Cite as

Acid sphingomyelinase deficiency. Phenotype variability with prevalence of intermediate phenotype in a series of twenty-five Czech and Slovak patients. A multi-approach study

  • H. Pavlů-Pereira
  • B. Asfaw
  • H. Poupčtová
  • J. Ledvinová
  • J. Sikora
  • M. T. Vanier
  • K. Sandhoff
  • J. Zeman
  • Z. Novotná
  • D. Chudoba
  • M. Elleder
Article

Summary

A multi-approach study in a series of 25 Czech and Slovak patients with acid sphingomyelinase deficiency revealed a broad phenotypic variability within Niemann–Pick disease types A and B. The clinical manifestation of only 9 patients fulfilled the historical classification: 5 with the rapidly progressive neurovisceral infantile type A and 4 with a slowly progressive visceral type B. Sixteen patients (64%) represented a hitherto scarcely documented ‘intermediate type’ (IT). Twelve patients showed a protracted neurovisceral course with overt or mild neurological symptoms, three a rapidly progressing fatal visceral affection with rudimentary neurological lesion. One patient died early from a severe visceral disease. The genotype in our patients was represented by 4 frameshift and 14 missense mutations. Six were novel (G166R, R228H, A241V, D251E, D278A, A595fsX601). The Q292K mutation (homoallelic, heteroallelic) was strongly associated with a protracted neurovisceral phenotype (10 of 12 cases). The sphingomyelin loading test in living fibroblasts resulted in total degradation from less than 2% in classical type A to 70–80% in classical type B. In the IT group it ranged from 5% to 49% in a 24 h chase. The liver storage showed three patterns: diffuse, zonal (centrolobular), and discrete submicroscopic. Our series showed a notable variability in both the neurological and visceral lesions as well as in their proportionality and synchrony, and demonstrates a continuum between the historical ‘A’ and ‘B’ phenotypes of ASM deficiency. This points to a broad phenotypic potential of ASM deficiency, suggesting the existence of still unknown factors independently controlling the storage level in the visceral and neuronal compartments. This report highlights the important position of the IT in the ASM deficiency phenotype classification. We define IT as a cluster of variants combining clinical features of both the classical types. The protracted neuronopathic variant with overt, borderline or subclinical neurology prevails and is important in view of future enzyme replacement therapy. It appears more common in central Europe. The visceral, rapidly progressing early fatal type has been recognized rarely so far.

Keywords

Enzyme Replacement Therapy Classical Type Intermediate Type Fatal Type Liver Storage 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© SSIEM and Springer 2005

Authors and Affiliations

  • H. Pavlů-Pereira
    • 1
  • B. Asfaw
    • 1
  • H. Poupčtová
    • 1
  • J. Ledvinová
    • 1
  • J. Sikora
    • 1
  • M. T. Vanier
    • 3
  • K. Sandhoff
    • 4
  • J. Zeman
    • 2
  • Z. Novotná
    • 1
  • D. Chudoba
    • 5
  • M. Elleder
    • 1
    • 6
  1. 1.Institute of Inherited Metabolic DisordersCzech Republic
  2. 2.Department of PediatricsCharles University 1st Faculty of Medicine and University HospitalPragueCzech Republic
  3. 3.INSERM U189, Lyon-Sud Medical School, and Laboratoire Fondation Gillet MérieuxLyon-Sud HospitalPierre-BéniteFrance
  4. 4.Institute of Organic Chemistry and BiochemistryUniversity of BonnGermany
  5. 5.Institute of Biology and Medical GeneticsCharles University 2nd Faculty of Medicine and University Hospital MotolPragueCzech Republic
  6. 6.Institute of Inherited Metabolic DisordersPrague 2Czech Republic

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