Analysis of Pena Shokeir phenotype.

At this point in time, we recognize that "Pena Shokeir" is not a diagnosis or a specific syndrome but rather a description of a phenotype produced by fetal akinesia or decreased in utero movement. In its "full blown" form, it is characterized by polyhydramnios, intrauterine growth retardation, pulmonary hypoplasia, craniofacial and limb anomalies, congenital contractures, short umbilical cord, and lethality. From the cases thus far reported, we would anticipate that the phenotype is present in a very heterogeneous group of disorders--heterogeneous both with regard to the specific anomalies present and with regard to the causes (which must include many environmental agents and multiple genetic forms). One challenge for the future is to better describe and delineate specific entities. In the meantime, we would do well to use the terms "Pena Shokeir phenotype" or "fetal akinesia/hypokinesia sequence," which do not imply a single entity. There are many practical aspects of recognizing this phenotype. The presence of any one of the cardinal signs of the fetal akinesia/hypokinesia sequence should alert the physician to look for the other associated anomalies, since specific treatment may be indicated, and catch-up or compensatory growth may occur, if given a chance. The ability to provide prenatal diagnosis and perhaps prenatal treatment in the future may allow us to alter dramatically the natural history of some cases. In others, we need to establish when treatment is possible and when it gives no benefit. Perhaps the most important insight gained from the study of the fetal akinesia sequence is the reaffirmation of the concept that function is an integral part of normal development. Specific structures do not develop in isolation but are part of a carefully timed and integrated system. The "use" of a structure in utero is necessary for its continuing and normal development. The old adage "use it or lose it" seems to apply just as appropriately to prenatal normal development as it does in the crusty adult world of politics, business, and academia.