2 a number of drastic mutations can produce this kind of dwarfism , ranging from a defect in a gene that releases growth hormone to defects in genes that result in damage to the pituitary gland 注 as a whole 4多种剧烈的突变都可能导致这种侏儒症,其中包括从释放生长激素的一个基因的一个缺陷,到导致整个垂体损害的多个基因的多个缺陷。