Today’s guest post on genetic syndromes comes from Kelly Hungaski, who is contributing an informative piece on the Hurler Syndrome.
Hurler Syndrome is a rare, inherited metabolic disease in which a person can’t break down lengthy chains of sugar molecules called glycosaminoglycans. Hurler syndrome belongs to a group of diseases called mucopolysaccharidoses, or MPS.
MPS-1 is considered the most severe form of the disease. Persons with Hurler syndrome do not make a lysosomal alpha-L-iduronidase enzyme, which helps break down the above sugar molecules. These molecules are found throughout the body, often in mucus and in fluid around the joints. Without the enzyme,these sugars can build up and damage various organs such as the heart. Without treatment, the life expectancy for a child with Hurler’s Syndrome is between 5-10 years of age. MPS-1 symptoms can range from severe to mild.
MPS Types:
- MPS-I (Hurler’s Syndrome)
- MPS I H-S (Hurler-Scheie syndrome)
- MPS I S (Scheie syndrome)
Statistics
Hurler Syndrome is an inherited disease which is passed down by both the mother and father. It is equally common in males as females. It is reported to occur in approximately 1 in 100,000 births. Symptoms often appear between ages 3 and 8. Infants with severe form of Hurler appear normal at birth. Facial symptoms may become more noticeable during the first 2 years of life.
Development:
Children with Hurler Syndrome may at first grow faster than normal, however by the end of their first year that growth slows down and frequently ends altogether before age 3. Many children develop a short body trunk and a maximum stature of less than 4 feet. Distinct facial features (including flat face, depressed nasal bridge, and bulging forehead) become more evident in the second year.
Physical Characteristics:
- Short stature
- Halted growth
- Low, flattened nasal bridge
- Thick coarse facial features
- Cloudy corneas
- Abnormal bones in the spine
- Deafness
- Enlarged tongue
- Impaired cognition
- Heart Problems
Medical Complications:
The most common effects of Hurler are cognitive impairment, skeletal and joint problems, vision and hearing impairments, heart, liver and lung diseases. Medical complications for children with Hurler’s syndrome include: sleep apnea, chronic ear infections, poor vision, hydrocephalus and poor hearing. Accumulation of the glycosaminoglycans can damage the heart, liver, spleen and lungs. Problems with joints including joint stiffness and skeletal anomalies have also been reported. Respiratory issues secondary to sleep apnea, large tonsils/adenoids and a short neck have also been reported. Cardiac and respiratory issues should be considered when planning interventions. Children with Hurler’s syndrome will require intensive Physical and Occupational therapy to teach fine motor and gross motor skills.
Cognition:
Children with Hurler Syndrome have intellectual disabilities with measurable decreases in IQ as they become older. There is a range in cognitive abilities for children diagnosed with MPS-1 diseases. Some children will only speak a few words and some children are able to read a little bit. Children with Hurler’s syndrome are able to acquire new skills but their developmental pace is slower than that of their same aged peers. Bone marrow transplants should stop or slow down the deterioration of mental development. However, bone marrow transplants are not able to repair damage which occurred prior to the transplant.
Speech and Language Issues:
There is limited research on speech and language issues or treatment strategies for children with Hurler’s syndrome. Speech and language development generally develops normally during the first year of life unless there are complications such as hydrocephalous or lack of oxygen. Development of speech and language skills begin to slow by 2 years of age. Children with Hurler’s syndrome will continue to make progress in their speech and language skills but at a slower rate than their same aged peers.
Children with Hurler Syndrome require speech and language therapy to help improve their ability to imitate sounds and words, improve their understanding of basic directions, and to improve their ability to express themselves. Language stimulation therapy is recommended before and after transplants with intensive therapy from birth to three during critical brain development period.
Some children may benefit from augmentative communication including American Sign Language, gestures, picture symbols or voice output devices.
Swallowing issues are not related to Hurler’s Syndrome, However, some children with Hurler’s syndrome may require feeding therapy to work on poor lip closure, limited jaw and tongue movements for feeding.
Children with Hurler’s syndrome should have their hearing checked frequently due to the high incidence of ear infections as well as progressive loss of hearing.
Current Interventions:
Current treatments are focused on slowing down or replacing the damaged enzymes. Treatments include bone marrow transplants and enzyme replacement therapy. Bone marrow transplants have been shown to be effective in slowing or stopping the progression of the disease and decreasing the mental decline seen in Hurler’s syndrome.
Researcher’s from the University of Adelaide are attempting to modify adult stem cells to produce extra amounts of the deficient enzyme which they will use to replace the damaged cells. This is promising research since it wouldn’t require the time it takes to find a perfect donor match which is needed with a bone marrow transplant.
Conclusion:
Hurler’s Syndrome is a genetic disorder which has a profound effect on individuals physical health, cognition, motor development and speech development.
References:
The Development of Cognitive Functions in Children with Hurler phenotype mucopolysaccaridosis type I on enzyme replacment therapy with laronidase Biernacka M, Jakubowska-Winecka A, Tylki-Saymanska A, Zaklad Psychologii Zdrowia. psychologia@cssd.pl
A Guide to Understanding MPS1, National MSP Society
A Note to Physical, Occupational and Speech Therapists: Treating Children with Hurler Syndrome, University of Minnesota Amplatz Hospital
MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [updated 2005 Aug 12]. Hurler’s syndrome; [updated 5/15/11} Jul 19; Available from: http://www.nlm.nih.gov/medlineplus/ency/article/001204.htm
Kelly Hungaski MS/CCC-SLP has been practicing as an ASHA certified speech language pathologist for the last 16 years. She has worked in a variety of settings including: clinics, schools, telepractice and in adult day work programs. Kelly has special interests in Autism, motor speech disorders, and social/pragmatic language skills. Her blog is called Speech2U.