Inactivation of one of the X chromosomes in females is a biological phenomenon of clinical importance

An immunoreactive theory of selective male affliction

Males are selectively afflicted with the neurodevelopmental and psychiatric disorders of childhood, a broad and virtually ubiquitous phenomenon that has not received proper attention in the biological study of sex differences. The previous literature has alluded to psychosocial differences, genetic factors and elements pertaining to male “complexity” and relative immaturity, but these are not deemed an adequate explanation for selective male affliction. The structure of sex differences in neurodevelopmental disorders is hypothesized to contain these elements: (1) Males are more frequently afflicted, females more severely; (2) disorders arising in females are largely mediated by the genotype; in males, by a genotype by environment interaction; (3) complications of pregnancy and delivery occur more frequently with male births; such complications are decisive and influence subsequent development. We hypothesize that there is something about the male fetus that evokes an inhospitable uterine environment. This “evocative principle” is hypothesized to relate to the relative antigenicity of the male fetus, which may induce a state of maternal immunoreactivity, leading either directly or indirectly to fetal damage. The immunoreactive theory (IMRT) thus constructed is borrowed from studies of sex ratios and is the only explanation consistent with negative parity effects in the occurrence of pregnancy complications and certain neurodevelopmental disorders. Although the theory is necessarily speculative, it is heuristic and hypotheses derived from it are proposed; some are confirmed in the existing literature and by the authors' research.

Renal manifestations in Fabry disease and therapeutic options

Fabry disease is an X-linked lysosomal storage disorder that affects both sexes. Progressive cellular accumulation of glycolipids starts early in life and, if untreated, eventually leads to organ failure and premature death. The Fabry nephropathy is characterized by initial proteinuria in the second to third decades of life, and development of structural changes including glomerular sclerosis, tubular atrophy, and interstitial fibrosis. Progressive kidney failure develops at a comparable rate as in diabetic nephropathy. First signs of kidney damage may arise in childhood, prior to first signs of overt renal dysfunction underscoring the key importance of early recognition and diagnosis. Globotriaosylceramide (GL-3) deposition is probably the initiating factor of the disease pathology and, with enzyme replacement therapy (ERT), clearance can be achieved in several cell types. However, some late-stage effects are not reversible. As there is growing evidence that renal outcomes are more directly related to the degree of fibrosis and scarring, preventing the development of these irreversible changes by early initiation of ERT may have the greatest impact on renal outcomes. Proteinuria should be rigorously monitored and aggressively treated with antiproteinuric therapy. This review describes the renal clinical features and histological changes, and outline options for therapeutic intervention that offer the best hope for patients affected by this life-threatening disorder.