Figure 4.

The electron-dense elements not counted as dense-granules are calcium- and phosphorus-poor veils [67] (A,B, arrows), clusters of spongy elements (C), also present in the form of chains or larger grains (D,E), which are found in abundance and bigger in STIM1–York–Stormorken pathologies and are rich in calcium and phosphorus [70], while others are poorer in calcium (F), which could represent immature dense-granules (possibly polyphosphate filaments without calcium accumulation, found in non-identified cases of delta deficiency, but not in Hermansky–Pudlak syndrome).