About jeune syndrome

What is jeune syndrome?

Asphyxiating thoracic dystrophy is a very rare form of congenital dwarfism affecting the development of the bone structure, particularly of the chest (thorax) but also of the legs and arms. Typical, major characteristics include failure of the rib cage to develop correctly, kidney problems (renal failure due to polycystitis), and shortened bones of the arms and legs.

What are the symptoms for jeune syndrome?

ATD is characterized by abnormal development of the rib cage (thorax) resulting in a small thoracic cavity. The characteristic “bell-shaped” chest cavity restricts the growth of the lungs and results in a variable degree of lung Hypoplasia and breathing problems (respiratory distress) in the newborn period.

Other clinical features that can be apparent at birth include too many fingers and/or toes (polydactyly), mild to moderate shortening of the long bones of the arms and legs (micromelia), insufficient growth of the pelvic bones, and cardiac defects.

Patients typically present in the newborn period with variable degrees of respiratory distress and recurrent respiratory infections. These breathing problems are the most serious complications of ATD and are the main cause of mortality in these patients. Some reports indicate that 50-60% of children with ATD die in infancy or during the first few years after birth. For those patients that live into early childhood, the breathing problems tend to improve with age such that a subset of patients may live into adolescence or adulthood.

Other complications of ATD can occur as the child grows including: high blood pressure, renal cysts, pancreatic cysts, and, less commonly liver diseases, dental abnormalities, and reduced or deteriorating vision (retinal dystrophy).

Affected individuals may develop chronic nephritis (a kidney condition) that may lead to kidney failure or malfunctions. Heart abnormalities and narrowing of the airway may also occur.

What are the causes for jeune syndrome?

Mutations in 24 genes have been found to cause ATD to date. The genes are: IFT43/52/80/81/122/140/172, WDR19/34/35/60, DYNC2H1, DYNC2LI1, CEP120, NEK1, TTC21B, TCTEX1D2, INTU, TCTN3, EVC 1/2 and KIAA0586/0753.

It is estimated that 70 percent of affected individuals have mutations in one these genes. Mutations in these genes result in abnormal cilia proteins that affect bone development.

What are the treatments for jeune syndrome?

Treatment is based on managing respiratory infections and monitoring renal and hepatic function regularly. The risk of severe respiratory infections diminishes after age two.

The vertical expandable prosthetic titanium rib (VEPTR) was approved by the FDA in 2004 as a treatment for thoracic insufficiency syndrome (TIS) in pediatric patients. TIS is a congenital condition where severe deformities of the chest, spine, and ribs prevent normal breathing and lung development. The VEPTR is an implanted, expandable device that helps straighten the spine and separate ribs so that the lungs can grow and fill with enough air to breathe. The length of the device can be adjusted as the patient grows. For treatment of spondylothoracic dysplasia, ribs are separated on each side of the chest and VEPTRs are placed on each side of the chest.

What are the risk factors for jeune syndrome?

ATD is inherited in an autosomal recessive pattern. Recessive genetic disorders occur when an individual inherits a non-working gene from each parent. If an individual receives one working gene and one non-working gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the non-working gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier, like the parents, is 50% with each pregnancy. The chance for a child to receive working genes from both parents is 25%. The risk is the same for males and females

Males and females appear to be affected in equal numbers, as do persons of various ethnic or racial backgrounds.

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