Failure to detect Fabry patients in a cohort of prematurely atherosclerotic males.

Fabry disease, or alpha-galactosidase A (alpha-Gal A) deficiency, is a lysosomal storage disorder in which accumulation of globotriaosylceramide (Gb(3)) is thought to be responsible for the development of renal, cardiac and cerebral complications. The availability of enzyme replacement therapy has led to an increased awareness and the screening of patients suffering from complications that may be associated with Fabry disease. An association between alpha-Gal A deficiency and atherosclerosis has been suggested, although there is controversy. We therefore studied the prevalence of Fabry disease in a Dutch cohort of prematurely atherosclerotic males. Measurement of alpha-Gal A activity was performed in plasma of 440 Dutch male patients with premature atherosclerosis. Patients were included if they were under the age of 50 years and had proven coronary and/or peripheral artery disease. Analysis revealed a mean alpha-Gal A activity of 7.75 +/- 3.48 nmol/h per ml (range 0.55-34.36). In 425 patients (96.5%) alpha-Gal A activity was within the reference range (3.2-14.3 nmol/h per ml, based on historical controls); 13 patients (3%) had values above and 2 patients (0.5%) below the reference range. Additional analysis of alpha-Gal A activity in leukocytes and fresh plasma in these two patients revealed normal values (53 and 47 nmol/h per mg (reference range: 32-60 nmol/h per mg) and 31.1 and 14.2 nmol/h per ml, respectively). Thus Fabry disease was not detected, leading to an overall prevalence of 0% (95 CI 0-0.68). In conclusion, screening for Fabry disease in prematurely atherosclerotic patients seems not to be very useful, although a slightly increased prevalence is not excluded.

Plasma chitotriosidase in male Fabry patients: a marker for monitoring lipid-laden macrophages and their correction by enzyme replacement therapy.

Increased plasma chitotriosidase is a well established surrogate marker for the occurrence of lipid-laden macrophages in the glycosphingolipidosis Gaucher disease. The complete lack of surrogate markers for Fabry disease, X-linked globotriaosylceramidosis stemming from deficiency in the lysosomal alpha-galactosidase A (AGA), prompted us to study chitotriosidase in this disorder. In male Fabry patients plasma chitotriosidase is significantly elevated, consistent with the presence of lipid-laden macrophages in several tissues. Increased levels are detectable at very young age and precede clinical manifestations. No strict correlation exists with severity of disease manifestations. Upon therapy with either of the two available recombinant AGA preparations, plasma chitotriosidase levels are nicely normalized in male Fabry patients. However, in patients developing neutralizing antibodies towards AGA, reduction in plasma chitotriosidase is hampered. In sharp contrast to the situation in male patients, females heterozygous for AGA deficiency show no significantly elevated plasma chitotriosidase. This suggests that circulating endogenous AGA in heterozygotes is sufficient to supplement enzyme-deficient macrophages. In conclusion, for the first time a biological marker for lipid-laden cells in Fabry patients is demonstrated; elevated plasma chitotriosidase levels reflecting lipid-laden macrophages. Corrections in this marker illustrate the efficacy of enzyme replacement therapy in clearing the lipid accumulation in this particular cell type.

A novel member of the transmembrane serine/threonine kinase receptor family is specifically expressed in the gonads and in mesenchymal cells adjacent to the müllerian duct.

The activin and TGF-beta type II receptors are members of a separate subfamily of transmembrane receptors with intrinsic protein kinase activity, which also includes the recently cloned TGF-beta type I receptor. We have isolated and characterized a cDNA clone (C14) encoding a new member of this subfamily. The domain structure of the C14-encoded protein corresponds with the structure of the other known transmembrane serine/threonine kinase receptors. It also contains the two inserts in the kinase domain that are characteristic for this subfamily. Using in situ hybridization, C14 mRNA was detected in the mesenchymal cells located adjacent to the müllerian ducts of males and females at day 15 (E15) of embryonic development. Marked C14 mRNA expression was also detected in the female gonads. In female E16 embryos, the C14 mRNA expression pattern remained similar to that in E15 embryos. However, in male E16 embryos C14 mRNA was detected in a circular area that includes the degenerating müllerian duct. The expression of C14 mRNA was also studied using RNase protection assays. At E15 and E16, C14 mRNA is expressed in the female as well as in the male urogenital ridge. However, at E19, a high C14 mRNA level in the female urogenital ridge contrasts with a lack of C14 mRNA in the male urogenital ridge. This correlates with the almost complete degeneration of the müllerian ducts in male embryos at E19. C14 mRNA expression was also detected in embryonic testes at E15, E16 and E19 using RNase protection assays, but at much lower levels than those found in the developing ovaries.(ABSTRACT TRUNCATED AT 250 WORDS)