Pena-Shokeir syndrome (PSS) (OMIM 208150) is a rare, early lethal disorder with an estimated incidence of 1:12,000 [1-3]. Approximately one hundred cases have been reported . It was first identified by Pena and Shokeir in 1974 , although early descriptions resulted in the eponym, it has recently been suggested that Pena-Shokeir is not a specific unitary diagnosis or syndrome, but rather a description of a clinically and genetically heterogeneous phenotype from variable etiology, resulting from the reduction of movements in the uterus due to an intrinsic pathology regardless of the cause, and was subsequently included among the phenotypes associated with the fetal akinesia/hypokinesia deformation sequence (FADS) . In some families it has been suggested a recessive autosomal inheritance, and identified homozygosity for a frameshift mutation in the RAPSN gene, and homozygous truncating mutation in the DOK7 gene . In pathogenesis has also identified several infants with PSS, born of mothers with myasthenia gravis ; or associated with other autosomal dominant diseases .
Prenatal diagnosis of PSS is feasible as early as 14th week of gestation [8,9]. The abnormal neural development results in fetal akinesia/hypokinesia (decrease in fetal movements), with secondary arthrogryposis (contractures of the joints) and skeletal dysplasia. Prenatal ultrasonography may reveal polyhydramnios, short umbilical cord, and pulmonary hypoplasia. In addition to neurogenic arthrogryposis, PSS is characterized by intrauterine growth restriction, various cranio-facial anomalies (microcephaly, micrognathia, cleft-palate deformity, ocular hypertelorism, low-set and malformed ears, and a depressed nasal tip) camptodactyly, and pulmonary hypoplasia . Skeletal deformities like scoliosis, kyphoscoliosis, pectus carinatum, congenital hip dislocation, rocker-bottom feet, and syndactyly may accompany. These manifestations vary in severity, but are usually severe. Pulmonary hypoplasia is obligatory in PSS and cannot be found in others subtypes of fetal akinesia such as the arthrogryposis multiplex congenital (AMC). Involvements of cardiovascular, genitourinary (cryptorchidism), endocrine, and gastrointestinal systems have been reported [3,10]. In most cases, intelligence was impaired.
Approximately 30% of affected infants are stillborn, otherwise in live births death generally occurs during neonatal period or soon thereafter due to developmental delay, and respiratory and neurological problems. The ultimate prognosis for children with PSS is mostly dependent on the severity of pulmonary hypoplasia.
Two variants of this syndrome have been described and are commonly referred to as PSS Type I and II. Pena-Shokeir syndrome Type II (cerebro-oculo-facio-skeletal syndrome) differentiated from PSS Type I by the presence of microcephaly, ocular findings (microphthalmia, blepharophimosis, and/or cataracts), and by the lack of pulmonary hypoplasia [2,11].