The following report from the MHC-database is based on the latest version of the Mun-H-Center Observation Chart that has been in use since 2008. Please note, that this report exclude children younger than 3 years.
Reports based on the original forms (1996-2008) are presented at the bottom of this page - below the description of the diagnosis
Illustrations: Anders Nyberg
Estimated occurrence
15 - 20:100 000 live births
Etiology
Autosomal dominant hereditary trait. Most frequently spontaneous mutation.
General symptoms
Most children born with Noonan syndrome have some kind of cardiac defect. Short stature – adult individuals with Noonan syndrome are generally about 15 cm shorter than predicted height. Growth hormone production deficit. Late onset puberty is common, and in many boys the testicles remain undescended. Some individuals have delayed psycho-motor development and intellectual disabilities. There may be some increased tendency to bleed, but this is not severe.
Orofacial/odontological symptoms
A characteristic appearance with drooping eyelids, wide-set eyes, slanted eyes, an extra skin fold at the inner angle of the eyes, and short neck. Feeding difficulties are common, particularly during the first years of life. Some children have a great deal of vomiting. Owing to eating and swallowing difficulties, some children with Noonan syndrome need to eat often, and require a special diet. This may lead to an increased risk of tooth decay. High palate, late teething and small jaws with closely-spaced teeth have all been reported. However, it is difficult to establish exactly how much more common this is in children with Noonan than in others.
Orofacial/odontological treatment
- Children with eating disorders often require extra dental care, including assistance with oral hygiene and fluoride treatments. However, the dental services should not advise on eating difficulties.
- Regular check-ups of dental and jaw development. Orthodontist should be consulted when needed.
- An increased tendency to bleed may result in complications when teeth are extracted.
- Oral motor training and stimulation may be relevant in cases of eating difficulties, speech impairment and drooling.
- Feeding and swallowing difficulties are investigated and treated by a specialist team at the hospital or multidisciplinary treatment center.
- When treating medically compromised patients always contact their doctors for medical advice (bleeding problems, heart diseases etc).
Sources
The rare disease database of the Swedish National Board of Health and Welfare.
The MHC database - The Mun-H-Center database on oral health and orofacial function in rare diseases.
Noonan syndrom – folder from Smågruppscentrum.
