Noonan's syndrome
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Introduction
Male phenotype of Turner's syndrome.
Etiology
may occur in association with neurofibromatosis
Epidemiology
- male:female ratio 1:1
- common, 1 in 1000-2500 live births
Pathology
- congenital heart disease
- pulmonary valvular stenosis
- cardiomyopathy, generally hypertrophic
- SOS1 mutations engender a high prevalence of
- pulmonary valve disease
- atrial septal defects are less common
- elevated central venous pressure
- prominent a wave
- late-peaking systolic murmur
- pigeon breast (pes excavatum)
- webbing of neck
- antimongoloid slanting of palpebrae
- cryptorchidism
Genetics
- genetically heterogeneous
- type 4: autosomal dominant, involves SOS1 gene
- defects in neurofibromin when associated with neurofibromatosis
- type 3: autosomal dominant, associated with defects in KRAS
- type 1: autosomal dominant, associated with defects in PTPN11
- associated with defects in BRAF
- genes notes in CPT panel[6]
Clinical manifestations
- dysmorphic facial features
- neck webbing
- low hairline
- short stature
- hypertelorism
- cardiac anomalies
- deafness
- motor delay
- bleeding diathesis
- renal malformation
- pubertal delay, cryptorchidism
- developmental or behavioral problems
- vision problems, hearing loss
- lymphedema
- most patients are intellectually normal as adults[6]
Laboratory
- Noonan syndrome genomic sequence analysis
- see ARUP consult[7]
Diagnostic procedures
Differential diagnosis
- Down's syndrome
- pulmonary valve stenosis generally not present unless in association with tetralogy of Fallot[4]
Management
- repair of severe pulmonary valvular stenosis regardless of symptoms[4][5]
More general terms
- congenital heart disease; congenital cyanotic heart disease
- genetic disease of the heart
- genetic syndrome (multisystem disorder)
- developmental disorder syndrome (multisystem disorder)
Additional terms
- Noonan syndrome-like disorder with or without juvenile myelomonocytic leukemia
- Noonan-like syndrome (Noonan-like/multiple giant cell lesion syndrome)
- Turner syndrome (ovarian agenesis)
References
- ↑ Stedman's Medical Dictionary 26th ed, Williams & Wilkins, Baltimore, 1995
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 47
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1038
- ↑ 4.0 4.1 4.2 4.3 Medical Knowledge Self Assessment Program (MKSAP) 17, 18. American College of Physicians, Philadelphia 2015, 2018
- ↑ 5.0 5.1 Burch M, Sharland M, Shinebourne E et al Cardiologic abnormalities in Noonan syndrome: phenotypic diagnosis and echocardiographic assessment of 118 patients. J Am Coll Cardiol. 1993 Oct;22(4):1189-92 PMID: https://www.ncbi.nlm.nih.gov/pubmed/8409059
- ↑ 6.0 6.1 6.2 Bhambhani V, Muenke M. Noonan syndrome. Am Fam Physician. 2014 Jan 1;89(1):37-43. PMID: https://www.ncbi.nlm.nih.gov/pubmed/24444506 Free PMC Article
- ↑ 7.0 7.1 ARUP Consult: Noonan Spectrum Disorders Panel https://arupconsult.com/ati/noonan-spectrum-disorders-panel