Type I Pena-Shokeir syndrome is a congenital disorder characterized by several craniofacial and neurological features resulting from fetal akinesia. Earlier, the condition was regarded as a specific phenotype, but more recent research has proved that it ought to be regarded as a "fetal akinesia deformation sequence". Characteristic features of Pena-Shokeir syndrome include neurogenic arthrogyposis, camptodactyly, pulmonary hypoplasia, poyhydramnios, intrauterine growth retardation, limb contractures, craniofacial and limb anomalies, and a short umbilical cord. Typical facial features include low-set ears, hypertelorism, a short neck, scalp edema, micrognathia, and cleft palate. Other abnormalities, such as microcephaly and diaphragmatic hernia, may also be seen. It is estimated that one in every 12,000 infants worldwide is affected with this condition. A very significant portion of affected fetuses are stillborn, while those surviving do not usually live longer, and succumb to pulmonary complications.

Pena-Shokeir syndrome shows an autosomal recessive pattern of inheritance. Homozygous mutations in MUSK gene has been identified as causative among affected fetuses. Similar observations have been made in mice model with disrupted MuSK gene expression.

It is suggested that the condition is caused as a result of cerebral lesions during development in association with genetic defects. The time of onset of these lesions in the embryonal life decides the severity of the syndrome and the specific features of the condition.