- Facial dysmorphism - intellectual deficit - short stature - hearing loss
- Laryngotracheal stenosis, arthropathy, prognathism, and short stature
- LAPS syndrome
- Growth mental deficiency syndrome of Myhre
Your QuestionMy 2 1/2 year old daughter has just been diagnosed with Mhyre syndrome. Could you provide me with information about this condition? Is there anything we should be aware of for later in life?
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Questions on this page
- Delayed development of language and motor skills such as crawling and walking
- Intellectual disability that ranges from mild to moderate
- Behavioral issues such as features of autism or related developmental disorders affecting communication and social interaction
- Hearing loss, which can be caused by changes in the inner ear (sensorineural deafness), changes in the middle ear (conductive hearing loss), or both (mixed hearing loss)
- Reduced growth, beginning before birth and continuing through adolescence and affecting weight and height (many are shorter than about 97 percent of their peers)
- Stiffness of the skin resulting in a muscular appearance
- Skeletal abnormalities including thickening of the skull bones, flattened bones of the spine (platyspondyly), broad ribs, underdevelopment of the winglike structures of the pelvis (hypoplastic iliac wings), and unusually short fingers and toes (brachydactyly)
- Joint problems (arthropathy), including stiffness and limited mobility
- Typical facial features including narrow openings of the eyelids (short palpebral fissures), a shortened distance between the nose and upper lip (a short philtrum), a sunken appearance of the middle of the face (midface hypoplasia), a small mouth with a thin upper lip, and a protruding jaw (prognathism)
- An opening in the roof of the mouth (a cleft palate), a split in the lip (a cleft lip), or both
- Constriction of the throat (laryngotracheal stenosis)
- High blood pressure (hypertension)
- Heart or eye abnormalities
- In males, undescended testes (cryptorchidism)
Some researchers believe that the SMAD4 gene mutations that cause Myhre syndrome impair the ability of the SMAD4 protein to attach (bind) properly with the other proteins involved in the signaling pathway. Other studies have suggested that these mutations result in an abnormally stable SMAD4 protein that remains active in the cell longer. Changes in SMAD4 binding or availability may result in abnormal signaling in many cell types, which affects development of several body systems and leads to the signs and symptoms of Myhre syndrome.
- Myhre Syndrome. National Organization for Rare Disorders (NORD). 2004; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/1075/viewAbstract. Accessed 3/17/2014.
- Myhre syndrome. Genetics Home Reference (GHR). Januray 2013; http://ghr.nlm.nih.gov/condition/myhre-syndrome. Accessed 3/17/2014.