Clinical Features of Stickler Syndrome
Stickler Syndome is an autosomal dominant condition affecting the proteins involved in the production of collagen. The three most common collagen genes which are know to cause Stickler Syndrome are called: COL 2A1, COL 11A1 and COL 11A2. Depending on the gene involved the condition does differ slightly (Research).
COL2A1 Type 1 Stickler Syndrome
COL11A1 Type 2 Stickler Syndrome
COL11A2 Non ocular variant. This does not affect the eyes and does not therefore have an increased risk of retinal detachment and will not be considered further here.
SIGNS & SYMPTOMS
Due to the large size of the Stickler genes and the different way in which each gene can be affected, the clinical signs can vary considerably between patients and families and even between affected individuals within the same family.
Even on genetic analysis it is not always possible to predict with accuracy the absence or severity of any of the above symptoms. Some sub-groups of Type 1 Stickler syndrome have a reduced risk of arthritis but all have a high risk of retinal detachment.
- Cleft Palate. Children may be born with varying degrees of cleft in the palate from bifid (double) uvula, sub-mucosal cleft through to a full hard and soft palate division.
Some children are born with Pierre Robin Sequence, which involves a cleft palate and micrognathia, (small chin) are also found to have Stickler Syndrome.
- Hearing Problems. One of the effects of cleft palate and consequent surgery is that children may be more susceptible to repeated bouts of glue ear and its associated hearing loss. However, in addition to this, Stickler Syndrome can also affect the development of the inner ear resulting in a neural hearing loss, which is typically present from birth, affects high tones and may be so subtle that it may only be picked up on special test called an audiogram. Abnormalities of the tympanic membrane (ear-drum) have also been found in Stickler syndrome.
- High Myopia. In general, children are normally born long sighted and grow out of it as they get older. In contrast children with Stickler Syndrome are often born myopic (short-sighted) and may be very short-sighted indeed even when still young.
- Cataracts. Patients can be born with mild quadrantic cataracts which may go unnoticed or they can develop cataracts at an earlier age than is usually expected.
- Retinal Detachment. All patients with ocular variants of Stickler syndrome (especially type 1 Stickler syndrome) are at high risk of retinal detachment, which can affect both eyes.
- Hypermobility. Stickler syndrome is one of the many connective tissue disorders known to be associated with hypermobility. It is often noted that affeteced children have unusually bendy fingers, ankles, knees and elbows. Some complain of aching limbs after normal, energetic childhood activities.
- Arthropathy. Due to the deficient collagen the cartilage in the joints, especially the larger weight bearing ones (and perhaps hypermobility in youth causes inappropriate wear and tear) patients with Stickler Syndrome can develop earlier onset arthritis than would be expected in the general population.
- Facial Appearance. In many cases it will be noticed that a patient has a flat mid-face or no bridge to their nose. In many cases this diminishes with age as their features develop.
CARE OF PATIENTS WITH STICKLER SYNDROME
- Cleft palates, if necessary, are surgically repaired at an early age.
- Hearing problems in association with clefts require close monitoring and sometimes insertion of grommets if the child suffers persistent glue ear. Any additional associated neural hearing loss as a result of Stickler syndrome is usually mild in most patients, but occasionally might be severe enough to require hearing aids.
- Regular Ophthalmic examinations are required by an experienced Vitreoretinal specialist to ensure there are no retinal holes, breaks or detachments which require treatment. It is also important to monitor the development of the vision to ensure that there is binocular vision and regular refraction for glasses.
- Hypermobility is often more pronounced in childhood. Assessment and advice from a rheumatologist is valuable in order to allow the child to lead a normal active childhood. Exercises may be given to strengthen the soft tissues supporting the joints in order to minimise the effects of hypermobility.
- Arthropathy is treated as or when (or even, if) it develops. It is sensible to minimise weight gain and to remain supple with exercise and good diet.
- Congenital cataracts may not affect the vision as they are often 'off centre' and can be left alone. Premature cataract which develop and do diminish the visual acuity can be removed by surgery.
- Retinal detachments can be repaired and sight restored but it is an emergency situation and should not be left. Those Type 1 Stickler patients at risk of a Giant Retinal Tear are offered prophylactic (preventative) surgery to reduce their risk. (Further Info)
- Stickler Syndrome Support Group - www.stickler.org.uk