Noonan Syndrome is a genetic disorder that impairs normal development of several parts of the body. The main features of Noonan Syndrome include unusual facies (hypertelorism, down-slanting eyes, webbed neck), congenital heart disease, short stature and chest deformity. Mental retardation can be seen in approximately 25% of individuals affected by Noonan syndrome. Other findings present to varying degrees include skeletal, neurologic, genitourinary, lymphatic, eye and skin manifestations. Gene mutations identified in individuals with Noonan Syndrome phenotype are involved in the RAS/MAPK (mitogen-activated protein kinase) signal transduction pathway, also known as RASopathy. RASopathies are developmental syndromes caused by germline mutations in genes that alter the RAS subfamily and MAPK that control signal transduction and that present overlapping clinical features. Some of the diseases belonging to this category include Noonan syndrome, Costello syndrome, Neurofibromatosis type 1, cardio–facio–cutaneous syndrome and others. The most common mode of inheritance for these diseases is autosomal dominant.
The Igenomix Noonan Spectrum Disorders and RASopathies Precision Panel can be used to make a directed and accurate differential diagnosis of Noonan syndrome and RASopathies ultimately leading to a better management and prognosis of the disease. It provides a comprehensive analysis of the genes involved in this disease using next-generation sequencing (NGS) to fully understand the spectrum of relevant genes involved.
- The Igenomix Noonan Spectrum Disorders and RASopathies Precision Panel is indicated for those patients with a clinical diagnosis presenting with the following manifestations:
- Facial features: triangular-shaped face, hypertelorism, down-slanting palpebral fissures, ptosis, low set ears etc
- Ocular abnormalities: amblyopia, myopia, astigmatism, strabismus etc
- Sensorineural hearing loss
- Pectus carinatum or excavatum
- Cardiac abnormalities: pulmonary stenosis, hypertrophic cardiomyopathy
- Skeletal features: joint laxity, short stature etc
- Skin abnormalities
- Genitourinary abnormalities
The clinical utility of this panel is:
- The genetic and molecular confirmation for an accurate clinical diagnosis of a symptomatic patient.
- Early initiation of treatment with a multidisciplinary team to perform appropriate medical care, early surveillance of malignancy and surgical repair of anatomic abnormalities.
- Risk assessment of asymptomatic family members according to the mode of inheritance.
- Improvement of delineation of genotype-phenotype correlation.
Romano, A. A., Allanson, J. E., Dahlgren, J., Gelb, B. D., Hall, B., Pierpont, M. E., Roberts, A. E., Robinson, W., Takemoto, C. M., & Noonan, J. A. (2010). Noonan syndrome: clinical features, diagnosis, and management guidelines. Pediatrics, 126(4), 746–759. https://doi.org/10.1542/peds.2009-3207
Turner, A. (2011). Noonan syndrome. Journal Of Paediatrics And Child Health, 50(10), E14-E20. doi: 10.1111/j.1440-1754.2010.01970.x
Cessans, C., Ehlinger, V., Arnaud, C., Yart, A., Capri, Y., & Barat, P. et al. (2016). Growth patterns of patients with Noonan syndrome: correlation with age and genotype. European Journal Of Endocrinology, 174(5), 641-650. doi: 10.1530/eje-15-0922
Turner A. M. (2014). Noonan syndrome. Journal of paediatrics and child health, 50(10), E14–E20. https://doi.org/10.1111/j.1440-1754.2010.01970.x
Allanson, J., Bohring, A., Dörr, H., Dufke, A., Gillessen-Kaesbach, G., & Horn, D. et al. (2010). The face of Noonan syndrome: Does phenotype predict genotype. American Journal Of Medical Genetics Part A, 152A(8), 1960-1966. doi: 10.1002/ajmg.a.33518
Liao, J., & Mehta, L. (2019). Molecular Genetics of Noonan Syndrome and RASopathies. Pediatric endocrinology reviews : PER, 16(Suppl 2), 435–446. https://doi.org/10.17458/per.vol16.2019.lm.molecularnoonan
Rauen K. A. (2013). The RASopathies. Annual review of genomics and human genetics, 14, 355–369. https://doi.org/10.1146/annurev-genom-091212-153523
Aoki, Y., Niihori, T., Inoue, S., & Matsubara, Y. (2016). Recent advances in RASopathies. Journal of human genetics, 61(1), 33–39. https://doi.org/10.1038/jhg.2015.114