The D313Y variant in the GLA gene - no evidence of a pathogenic role in Fabry disease.

Fabry disease is an X- linked inherited lysosomal storage disease caused by mutations in the GLA gene encoding the lysosomal enzyme alpha-galactosidase A (α-Gal A). The possible pathological significance of the D313Y variant in the GLA gene has not been verified and it may be a Fabry variant. Our aim was to elucidate whether the presence of the D313Y variant influenced the α-Gal A activity or resulted in Fabry symptoms or Fabry organ involvement. In two Danish families the presence of the D313Y variant did not result in reduced α-Gal A activity or clinical Fabry manifestations in males, and the presence in Fabry females did not significantly enhance the phenotype of a known causative mutation in the GLA gene (G271S). Our findings indicate that the D313Y variant is not causative to nor enhancing Fabry disease phenotype. The D313Y variant in the GLA gene was not disease causative in 2 Danish families. Investigating male family members were crucial in excluding the Fabry phenotype, and thus very important for proper genetic counceling of all family members, as well as overdiagnosing a devastating genetic disease.

Migration of phthalates on culture plates - an important challenge to consider for in vitro studies.

Phthalates are endocrine disruptors of the reproductive system and suspected to influence many other organ and hormone systems. They are also semi-volatile organic compounds present in the gas phase in the environment. Their mode of action has been investigated in numerous in vitro studies. Multi-well culture plates are typically used to study phthalates in cell cultures. In a pilot study, we observed evidence of phthalate migration in 24-well culture plates. As this has not previously been described, we investigated the phenomenon in more detail. Primary human thyroid epithelial cell cultures (n = 8 cultures) were exposed to either di-ethyl phthalate (DEP), di-n-butyl phthalate (DnBP), mono-n-butyl phthalate (MnBP) or di-(2-ethylhexyl) phthalate (DEHP). Measurement of phthalate metabolites by mass spectrometry demonstrated that the short-branched DEP was able to migrate to adjacent wells when added to cell culture plates. DnBP also seemed to be able to migrate, unlike the long-branched DEHP or the monoester MnBP which did not seem to have this ability. High background levels of phthalate metabolites were also observed, which might compromise results from low dose phthalate studies. In conclusion, the migration of phthalates which is probably caused by their volatile properties might lead to false interpretation of study results.

Clinical implications of residual growth hormone (GH) response to provocative testing in adults with severe GH deficiency.

CONTEXT: The diagnosis of GH deficiency (GHD) in adults is based on provocative tests of GH release, all influenced by clinical factors. It is unknown whether the amount of residual GH reserve under the cutoff value has any physiological implication. OBJECTIVES: We used a large pharmacoepidemiological database of adult GHD (KIMS) and tested the impact of confounding factors on GH release of no greater than 3 microg/liter after an insulin tolerance test (ITT) and evaluated its potential physiological role. DESIGN, SETTINGS, AND PATIENTS: A total of 1098 patients fulfilled the criteria of having a GH peak of no greater than 3 microg/liter during ITT as well as documented IGF-I levels. OUTCOMES: The impact of underlying hypothalamic-pituitary disease, age, gender, body weight, as well as treatment modalities such as irradiation on peak GH level to ITT was evaluated, and the correlations between GH peak and targets of GH action were analyzed. RESULTS: The GH response to ITT was regulated by gender, age, and the number of additional pituitary deficiencies. In a multivariate evaluation, the extent of hypothalamic-pituitary dysfunction was the most important single predictor of GH peak in ITT. GH peaks in ITT were positively related to IGF-I levels and high-density lipoprotein-cholesterol, as well as inversely to triglycerides. CONCLUSIONS: Even in adult severe GHD, GH release appears to be regulated by factors defined to play an important role in normal GH secretion. The impact of very low GH release on IGF-I and lipid parameters indicates a persistent physiological role of low GH concentrations in severely affected patients with GHD.