[The mid-growth spurt--a pre-puberty growth spurt. Review of its significance and biological correlations].

The MGS is a growth phenomenon during early childhood, expressed by a mild transitory acceleration of growth velocity between five and eight years of age. It appears to be more pronounced in boys than in girls. It is probably caused by the functional maturation of the adrenals ("adrenarche") which leads to an increased androgen production during this age. Interactions with the pituitary growth hormone, also presenting with increased secretion rates at this particular period, are very probable. A hypothesis is offered for the explanation of individual differences and distinctness of the MGS. Although the MGS cannot be interpreted as a very first step of puberty, some additional biochemical facts suggest fundamental changes in the organism. Therefore, the MGS could be regarded as a "marker" within the biological development of the child.