Short-Rib Polysyndactyly Syndrome

The Short-Rib Polysyndactyly syndrome is a descriptive category for a group of lethal skeletal dysplasias characterized by a hypoplastic thorax, short ribs, short limbs, polydactyly, and visceral abnormalities.

The Short-Rib Polysyndactyly Syndrome is subdivided into four types: classified as follow:

Type I: Saldino-Noonan Syndrome (Polysyndactyly with Neonatal Chondrodystrophy type I)

Type II: Majewski Syndrome (Polysyndactyly with Neonatal Chondrodystrophy type II)

Type III: Verma-Naumoff Syndrome (Polysyndactyly with Neonatal Chondrodystrophy type III)

Type IV:Beemer-Langer Syndrome (Short Rib Syndrome, Beemer type).

All variants are believed to be inherited as autosomal recessive pattern. However, because of the frequent phenotypic overlap, there is controversy as to whether the variants are because of variable expression or genetic heterogenity.

Type I or Saldino-Noonan Syndrome is a lethal condition (dwarfism) in the newborn period. The infant has a hydropic appearance, postaxial polydactyly, severely shortened and flipper-like limbs and striking metaphyseal dysplasia of tubular bones. Severe micromelia is often noted. The cardiac system often presents a transposition of the great vessels. Ossification is defective in the calvaria and vertebrae. It also affects the pelvis and bones of the hand and feet. The pelvis resembles that in the Ellis-van Creveld Syndrome and the Asphyxiating Thoracic Dystrophy Syndrome. The visceral abnormalities involve gastrointestinal (GI) atresia, genitourinary atresia, and polycystic kidneys.

Type II or Majewski Syndrome is a lethal disease in the perinatal period. It is characterized by the presence of median cleft-lip and palate, hypoplastic epiglottis, malformed larynx, and pulmonary hypoplasia. The presence of short ribs and GI atresia may mislead the diagnosis and often it is suggested to be a type I variant. However, the genitourinary system is largely affected with polycystic kidneys, ambiguous genitalia, and glomerular and renal tubular cysts. Neurologically, the presence of a hypoplastic cerebellar vermis and pachygyria is classical to this entity.

Type III or Verma-Naumoff Syndrome: The most important distinguishing features of this type are to be found in the skull: the cranial base is short, the forehead is bulging, the nasal bridge is depressed and the occiput is flat. Another difference resides in the radiologic appearance of the long tubular bones, which show a distinct corticomedullary demarcation, somewhat widened metaphyses and marked longitudinal spurs. The neonatal period is often associated with asphyxiating episodes because of the narrow thorax and very short ribs. In comparison with type II, the genitourinary system does not show as frequent abnormalities.

Type IV or Beemer Langer Syndrome is characterized by short ribs with pulmonary hypoplasia, associated with a variety of other visceral malformations. Short tubular bones, perinatal hydrops and macrocephaly are present in virtually all children. Midline cleft with or without cleft palate, congenital heart disease, central nervous system malformations, GI and urogenital abnormalities are other frequently encountered features. The syndrome is generally lethal with most children dying in utero or during early infancy because of respiratory insufficiency secondary to pulmonary hypoplasia.

Because of the dismal prognosis of all variants, these patients are unlikely candidates for anesthesia. If a surgical intervention is indicated, the full extent of craniofacial, cardiac malformations, and pulmonary functions needs to be assessed carefully.

Anesthetic implications vary according to the type involved. However, most of them present with potentially difficult airway management (especially type II), oxygenation failure on the ventilator, and severe difficulties to wean from the mechanical ventilation. The anesthetic considerations concerning the cardiovascular system depend on the pathophysiology of the underlying cardiac defect.

Depending on the cardiac state, agents causing myocardial depression or resulting in changes of systemic and/or pulmonary vascular resistance should be used cautiously.

Ellis-Van Creveld Syndrome: Polydactyly, and abnormalities of the ectoderm (dystrophy of the fingernails, change in the upper lip variously called “partial hare-lip,” lip-tie, cleft lip and palate) occurs. Micrognathia may be present. Frequent genital anomalies. Presence of cardiac malformations (usually a septal defect and often single atrium) in 60% of affected patients. Respiratory distress is common in the newborn because of pulmonary hypoplasia within a narrow dysplastic thorax with extremely short ribs. Dandy-Walker malformation, hydrocephalus. Management consists of dental care, orthopedic treatment of polydactyly, and correction of cardiac defects.

Jeune Syndrome: This asphyxiating thoracic dysplasia is a rare autosomal recessive chondrodysplasia that often leads to death in infancy because of a severely constricted thoracic cage and respiratory insufficiency. Most often associated with pulmonary hypoplasia, recurrent respiratory infections leading to respiratory insufficiency. Long, narrow thorax, short, horizontal ribs, handlebar clavicles, and bulbous irregular rib ends. The frequency is 1/100,000 to 1/130,000 live births. The survivors may develop renal failure and hepatic fibrosis, polycystic liver disease, jaundice, and pancreatic fibrosis. Proteinuria and hyperbilirubinemia must be assessed.