ABSTRACT
During embryonic development, bone formation begins with the condensation of mesenchymal stem cells. In a number of places in the body, such as the flat bones of the skull, bone formation is driven by a process called intramembranous ossification, where mesenchymal stem cells differentiate directly into bone-forming osteoblasts. Glucocorticoids, which are a subclass of steroid hormones, are quite commonly used as anti-inflammatory and immunosuppressive drugs in children. During puberty, estrogens and androgens are produced by the gonads and are associated with the pubertal growth spurt. This growth acceleration is primarily induced by estrogen rather than androgen, because a near-normal growth spurt is observed in individuals with androgen insensitivity. Malnutrition also strongly attenuates the reproductive axis, therefore decreasing the levels of both estrogen and androgen. One particular micronutrient that is important for bone homeostasis and bone growth is vitamin D. Epigenetics broadly refers to changes in gene functions without involving changes in the genomic DNA sequence.
