What Is Yunis Varon Syndrome?

Reviewed on 12/18/2020

Yunis Varon syndrome

Yunis Varon syndrome affects less than 200,000 people in the United States.
Yunis Varon syndrome affects less than 200,000 people in the United States.

Yunis Varon syndrome is an extremely rare, congenital (present at birth), genetic, and multisystem disorder. This syndrome affects the bones, hair, teeth, and systems of the heart and lungs in the body. Many children with this condition have characteristic facial features or abnormalities of fingers and toes. In most cases, babies who are born with this condition experience breathing and/or feeding challenges. It is listed as a rare disease by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). Yunis Varon syndrome affects less than 200,000 people in the United States. Signs and symptoms of Yunis Varon syndrome can vary widely in severity, even within the same family. Characteristics of Yunis Varon syndrome are:

  • Usually, patients have underdeveloped or absent collarbones (clavicles).
  • Narrow or sloped shoulders. In some cases, the shoulders can be made to meet in the middle of the body.
  • Delayed closing of the spaces between the bones of the skull (fontanels) is also characteristic of this condition. The fontanels usually close in early childhood but may remain open into adulthood in people with this disorder.
  • Affected individuals maybe 3 to 6 inch shorter than other members of their family
  • Short, tapered fingers, and broad thumbs
  • Short forearms
  • Flat feet
  • Knock knees
  • An abnormal curvature of the spine
  • A wide, short skull (brachycephaly)
  • A prominent forehead
  • Wide-set eyes (hypertelorism)
  • Flat nose
  • Small upper jaw
  • Abnormalities of the ears
  • Upturned nostrils
  • Developmental delays
  • Eyes that appear large or bulging
  • Heart problems (including cardiomyopathy or congenital heart conditions)
  • Intellectual problems
  • Disproportionately small head
  • Deformity of the pelvis
  • A small jaw that can cause problems with eating and breathing
  • Failure to thrive (a child who doesn’t grow or gain weight at the expected rate for their age)
  • Abnormalities of fingers and toes (such as missing or underdeveloped thumbs, toes, or pinky fingers)

Causes:

  • Yunis Varon syndrome is passed down in families (hereditary).
  • The imbalance of a rare second messenger called FIG4 mutations in the brain is the cause of Yunis Varon syndrome.
  • A history of marriage in close relatives (consanguinity).
  • There is a higher risk involved when both the parents are carriers and pass the defective gene and therefore, there is a 25% chance to have an affected child with each pregnancy. There is a 50% risk to have a child, who would be a carrier like the parents, with each pregnancy. The chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%.

Diagnosis:

  • Certain findings that may suggest a diagnosis of Yunis Varon syndrome (e.g. limb and bone abnormalities or a congenital heart defect) may be identified before birth (prenatally) using ultrasonography. In fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus.
  • Yunis Varon syndrome may be diagnosed or confirmed after birth based on a thorough clinical evaluation, which is the identification of signs and symptoms.
  • Genetic testing for mutations in FIG4 can also confirm a diagnosis.

Treatment and prognosis:

  • The syndrome is usually fatal in infancy.
  • Early intervention is considered important. For infants, breathing and feeding difficulties are monitored. Therapies used are “symptomatic and supportive.”
  • Symptomatic measures, such as corrective dental, facial, and orthopedic surgery, depending on the extent of accompanying abnormalities.
  • Medical and surgical therapy for treating respiratory distress and the need for adequate and early treatment in newborn infants.
  • Specific therapies for individuals with Yunis Varon syndrome are symptomatic and supportive. Treatment may require the coordinated efforts of a team of specialists. Pediatricians and specialists, who diagnose and treat skeletal abnormalities (orthopedists), physical therapists, physicians who specialize in diagnosing and treating disorders of the heart (cardiologists), and other health care professionals may need to systematically and comprehensively plan an effective treatment.
  • Physicians should closely monitor infants with Yunis Varon syndrome to promptly detect any feeding or breathing difficulties associated with the disorder.
  • Physicians may recommend preventive measures and/or institute immediate appropriate therapy.
  • Treatment for feeding difficulties may include artificial feeding methods, such as tube feeding that administers food through a tube directly into the infant’s stomach or intravenous feeding in which essential nutrients are administered into a vein using a tube.
  • Breathing difficulties, when severe and life-threatening, may require special measures, such as the use of a special machine (ventilator) that supports breathing (artificial respiration).
  • Special services that may be beneficial to affected children may include special remedial education, special social support, physical therapy, and other medical, social, and/or vocational services.
  • Genetic counseling will be of benefit for affected individuals and their families.

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References
Campeau PM, Lenk GM, Lu JT, et al. Yunis-VarĂ³n Syndrome Is Caused by Mutations in FIG4, Encoding a Phosphoinositide Phosphatase. Am J Hum Genet. May 2, 2013; 92(5): 781-791. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3644641/

Rare Disease Database. Yunis Varon Syndrome. National Organization for Rare Disorders (NORD). https://rarediseases.org/rare-diseases/yunis-varon-syndrome/#

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