[Achondrogenesis type I and II and hypochondrogenesis (author's transl)].

A study is made of achondrogenesis in relation to four observations of early fatal development. One case corresponds to type I (Parenti-Fraccaro); another to type II (Langer-Saldino); the final two, brothers, seem to come under the variation of hypochondrogenesis. In this study, authors stress the heterogenous nature of lethal, neonatal (short-limb) nanisms of which currently include: Type I and II achondrogenesis, hypochondrogenesis, homozygote achondroplasia, classical Torrance-type and San Diego-type thanatophoric dysplasia.