Pathogenesis of the lung in restrictive defects of Klinefelter's syndrome.

Patients with Klinefelter's syndrome show a high incidence of restrictive lung defects, the pathogenesis of which is not clear yet. We investigated the respiratory muscle force (PImax) and lung compliance in 13 patients with Klinefelter's syndrome who had not been receiving hormonal therapy for at least one year prior to being studied. Eleven were smokers and two were nonsmokers. None showed abnormalities of the chest wall. Five had normal lung volumes and eight showed a restrictive defect (TLC < 80 percent, VC < 85 percent, FEV1/FVC percent within normal values); DCOSB and arterial blood gases were within normal limits. PImax was similar in restricted (-115.9 +/- 26.7 cm H2O) and not restricted patients (-115.4 +/- 20.3 cm H2O), all within reference values. Lung compliance, however, was significantly decreased in the four patients studied (0.13 +/- 0.08 cm H2O-1) compared with five normal control subjects (0.29 +/- 0.05 cm H2O-1). We conclude that the likely cause of the lung restriction is a decrease of compliance of the lung matrix, probably related to the absence of testosterone.