The "discovery" of lipid droplets: A brief history of organelles hidden in plain sight.

Mammalian lipid droplets (LDs), first described as early as the 1880s, were virtually ignored for more than 100 years. Between 1991 and the early 2000s, however, a series of discoveries and conceptual breakthroughs led to a resurgent interest in obesity as a disease, in the metabolism of intracellular triacylglycerol (TAG), and in the physical locations of LDs as cellular structures with their associated proteins. Insights included the recognition that obesity underlies major chronic diseases, that appetite is hormonally controlled, that hepatic steatosis is not a benign finding, and that diabetes might fundamentally be a disorder of lipid metabolism. In this brief review, I describe the metamorphosis of LDs from overlooked globs of stored fat to dynamic organelles that control insulin resistance, mitochondrial oxidation, and viral replication.

CHILD syndrome avant la lettre.

The CHILD syndrome is an acronymic designation for congenital hemidysplasia with ichthyosiform nevus and limb defects. This X-linked dominant, male-lethal trait is caused by mutations in the gene NSDHL that is localized at Xq28 and involved in cholesterol metabolism. The CHILD nevus that constitutes a hallmark of this multisystem birth defect usually shows a striking lateralization pattern. Until now, a report of Zellweger and Uehlinger from 1948 was believed to represent the first published case of CHILD syndrome. However, we have now found an earlier report published in 1903 by Otto Sachs. An 8-year-old girl had a "xanthoma-like nevus" involving the right axillary region and a congenital muscular weakness of the right upper arm. Sachs described the clinical and histopathological features of CHILD nevus comprehensively, including the characteristic changes of verruciform xanthoma that can be taken within the group of epidermal nevi as a pathognomonic feature of CHILD nevus. This report is the earliest description of CHILD syndrome known so far. Moreover, Sachs presented in this article a comprehensive description of verruciform xanthoma, thus anticipating Shafer's "first report" of this histopathological phenomenon (1971) by almost 70 years.