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.

The Dutch Fabry cohort: diversity of clinical manifestations and Gb3 levels.

BACKGROUND: Fabry disease (OMIM 301500) is an X-linked lysosomal storage disorder with characteristic vascular, renal, cardiac and cerebral complications. Globotriaosylceramide (Gb(3)) accumulates in Fabry patients as a result of alpha-galactosidase A deficiency. The phenotypic variability is high, but the relationship between clinical symptoms in individual Fabry patients has not been uniformly documented. Also, the relation between the most prominent biochemical abnormalities, elevated Gb(3) levels in plasma and urine, and clinical symptoms is not firmly established. METHODS: Clinical and biochemical characteristics of 96 (25 deceased) Dutch Fabry patients were collected retrospectively and before the initiation of enzyme therapy. RESULTS: Clinical assessment revealed that median life expectancy was 57 years for male and 72 years for female patients. Cerebral complications, acroparaesthesias and gastrointestinal complications, but not cardiac and auditory complications, were all seen more frequently in male than female patients. Glomerular filtration rate (GFR) was highly variable in male patients, including 2 patients with GFR < 30 ml/min, but median GFR did not differ between males and females (103 and 101 ml/min, respectively). Hyperfiltration was more frequently observed in the female patient group. Microalbuminuria was present in 60% of males and 45% of females. No specific pattern of combined symptoms existed except for a relationship between left ventricular hypertrophy (LVH) and cerebral complications (males 36%, females 32%), or proteinuria (males 35%, females 31%). Gb(3) was found to be more elevated in plasma samples from male (n = 26; median 6.27 micromol/L (1.39-9.74)) than female Fabry patients (n = 37; median 2.16 (0.77-4.18)). This was also observed for urinary Gb(3): males (n = 22) median 1851 nmol/24 h (40-3724); females (n = 29) median 672 (86-2052). Plasma and urinary Gb(3) levels correlated with each other in both males (r = 0.4, p = 0.05) and females (r = 0.4, p = 0.03), but no correlation between elevated Gb(3) levels and clinical symptoms could be detected. CONCLUSION: Analysis of the characteristics of the Dutch Fabry cohort has revealed that a limited relationship between various disease manifestations exists and that individual symptoms do not correlate with elevated urinary or plasma Gb(3) levels, limiting their value as surrogate disease markers.

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.

Manifestations of Fabry disease in placental tissue.

Fabry disease is an X-linked lysosomal storage disorder caused by deficiency of the lysosomal enzyme alpha-galactosidase A. Manifestations of the disease in placental tissue have been reported only twice. We report for the first time on the biochemical, histological and genetic features of two cases: placenta A derived from a mother heterozygous for Fabry disease who gave birth to a hemizygous son, and placenta B obtained from a healthy mother who carried a heterozygous daughter. Biopsies of placentae A, B and of four healthy controls were taken directly after birth. Assessment of alpha-galactosidase A (alpha-Gal) activity was performed both in fetal leukocytes (derived from umbilical cord blood) and in the biopsy specimens. The tissue was further examined by electron microscopy, immunohistochemistry and biochemical analysis for the presence of storage material (ceramide trihexoside (CTH)). In placenta A, characteristic zebra bodies reflecting accumulated storage material were seen in all biopsies evaluated. CTH values were markedly elevated as compared to the controls and alpha-Gal activity in both fetal leukocytes and placental tissue was very low. Placenta B showed no storage material at all. CTH values were within the control range. alpha-Gal activity ranged from intermediate to near normal; enzyme activity in fetal leukocytes was significantly decreased. As placental tissue is mainly derived from fetal cells, we may conclude that, in a boy suffering from Fabry disease, extensive storage of CTH is already present at birth. As complications develop only around the age of 10 years, it may be not the CTH itself but secondary processes that cause cellular and organ damage.

Antimicrobial treatment of infective endocarditis caused by viridans streptococci highly susceptible to penicillin: historic overview and future considerations.

In this article we present the path that led to current concepts regarding antimicrobial treatment of endocarditis caused by viridans streptococci highly susceptible to penicillin. Early treatment trials indicate that some patients with subacute endocarditis can be cured with shorter treatment duration than currently advised by international guidelines. Also, high-dose antibiotics, as recommended today, have a predominantly pharmacokinetic and pharmacodynamic rationale that is based mostly on experimental animal studies. Shortening antimicrobial treatment in select patients with endocarditis would be of great benefit. As yet there are no predictors of cure that can be used to individualize treatment duration in patients with bacterial endocarditis.

Unexplained left ventricular hypertrophy: consider a diagnosis of Fabry's disease.

Lysosomal storage disorders are a group of disorders characterised by the deficiency of a specific lysosomal hydrolase. These diseases are rare, with only a few hundred patients in the Netherlands. Fabry's disease, an X-linked lysosomal storage disorder, is caused by a deficiency of the lysosomal enzyme α-galactosidase A which results in, among other things, left ventricular hypertrophy, renal failure and cerebrovascular events. Patients with Fabry's disease, especially males, have a decreased life expectancy. Recent studies have shown that Fabry's disease may be much more common among patients with left ventricular hypertrophy (LVH) than previously thought. Up to 7% of male patients with left ventricular hypertrophy and up to 12% of female patients with unexplained LVH were found to suffer from Fabry's disease. Thus, Fabry's disease should be considered in patients with unexplained LVH. This case report summarises the main features of the disease. In addition recent developments concerning prevalence, diagnosis and the current available treatments are discussed and an algorithm on who and how to screen for Fabry's disease is presented.