Contiguous gene syndromes are disorders caused by deletions of genes that are adjacent to one another. One of them is complex glycerol kinase deficiency. It is caused by partial deletion of Xp21, which includes the genes responsible for glycerol kinase deficiency, congenital adrenal hypoplasia, Duchenne muscular dystrophy and intellectual disability. There are no definite dysmorphic features for this syndrome. The diagnosis is based on clinical and laboratory findings. Symptoms depend on the size of deletion and appear almost exclusively in the male gender. Usually the first and most severe are the signs of adrenal hypoplasia, which, if not cured, may lead to death in a short time. The symptoms of glycerol kinase deficiency occur also early in life, but they may be masked by the deficiency of mineralocorticoids. Duchenne muscular dystrophy appears in childhood and is always accompanied by certain symptoms. Developmental retardation and intellectual disability occur often with complex glycerol kinase deficiency. The reasons for it are heterogeneous, but usually, there is a connection with the deletion of DMD or I L1R A P L genes. Due to the fact that loci of all genes responsible for complex glycerol kinase deficiency were determined, it is possible to carry out molecular examination, confirm clinical diagnosis and determine female carriers of the disorder.