Arthrogryposis is especially prominent in the hands. Arthrogryposis also involves the hips and the knees. Central and peripheral nervous system abnormalities are present. Pathologic findings reported in these patients include neurogenic atrophic muscle changes, and spinal cord and cerebellar histological abnormalities. Pulmonary hypoplasia results from decreased diaphragmatic motility. Neonates with Pena-Shokeir I syndrome are premature or small for gestational age. Pena-Shokeir I syndrome has been considered an autosomal recessive condition but more likely represents a typical phenotype that occurs as a consequence of decreased fetal movements at a particular gestational age.

Pena-Shokeir II Syndrome
Pena-Shokeir II syndrome, also known as cerebro-ocular-facio-skeletal syndrome, is characterized by cerebral, ocular, and skeletal abnormalities and characteristic facial features. The cerebral abnormalities consist of microcephaly, calcification of the lenticular nuclei, and hemispheric white matter, focal gliosis of the third ventricle, focal microgyria, and hypoplasia of the optic tract and chiasm. The ocular abnormalities include cataracts, blepharophimosis, and microphthalmia. Skeletal abnormalities include camptodactyly, prominent heels, rocket-bottom feet, and a longitudinal groove on the sole. Arthrogryposis primarily involves the elbows and knees. Radiographs of the lower extremities show shallow acetabular angle, coxa valga, posteriorly placed second metatarsal, and vertical talus. The characteristic facial features are thick scalp hair, large ears, prominent root of the nose, prominent upper lip that overlaps the lower lip, and micrognathia. Pena-Shokeir II syndrome is an autosomal recessive disorder.

Opitz Trigonocephaly Syndrome
Opitz trigonocephaly syndrome is characterized by trigonocephaly, upslanting palpebral fissures, hypoplastic nasal root, wide alveolar ridges, anomalous and posteriorly angulated ears, loose skin, heart anomaly, and arthrogryposis (distal). The head size is normal at birth but fails to grow postnatally. Mental retardation is constant. Opitz trigonocephaly syndrome is possibly an autosomal recessive disorder. Chromosomal anomalies (especially chromosome 3), Frydman trigonocephaly syndrome, and Say-Meyer trigonocephaly syndrome need to be excluded.

A	B	C

Figure 159.1— Opitz trigonocephaly syndrome. [A] trigonocephaly and hypoplastic nasal root; [B] 3-D CT demonstrating metopic and coronal suture synostosis; [C] CT brain demonstrating abnormal skull configuration and prominent subarachnoid space.

Smith-Lemli-Opitz Syndrome
Smith-Lemli-Opitz syndrome is characterized by microcephaly with a narrow frontal area, slanted or low-set ears, ptosis, anteverted nostrils, cryptorchidism, and hypospadias. The most important distinguishing features in males are cryptorchidism and hypospadias.

Figure 159.2.— Smith-Lemli-Opitz syndrome. [A] extradigit, mild arthrogryposis, and simian crease; [B] cryptorchidism and hypospadia.