Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

all patients

1st line – assessment ± specialist consult

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ACUTE
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all patients
1st line – 

assessment ± specialist consult

It is important to note specific medical conditions that are associated with NS. Some patients may not have the constellation of facial characteristics but may present with associated medical conditions. These include: skeletal abnormalities including chest deformity, variable degrees of developmental delay, ophthalmic and hearing deficits, coagulation defects; autoimmune disease; and lymphatic dysplasia. Appropriate investigations and specialist consults should be obtained.

Plus – referral to urology

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ACUTE
|
all patients
|
with cryptorchidism
Plus – 

referral to urology

Treatment recommended for ALL patients in selected patient group

The surgical approach is determined by surgeon preference, and is generally through an inguinal or scrotal incision.

Plus – cardiovascular assessment and evaluation for surgery

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ACUTE
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all patients
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with congenital heart anomalies
Plus – 

cardiovascular assessment and evaluation for surgery

Treatment recommended for ALL patients in selected patient group

These defects include dysplastic and/or stenotic pulmonary valve, hypertrophic cardiomyopathy, septal defects, and tetralogy of Fallot.[30][55][56][57]

Comprehensive cardiovascular evaluation at the time of diagnosis is imperative. Subsequent treatment will be guided by the specific anomaly identified.

Pulmonary valve stenosis and/or dysplasia may respond to balloon valvuloplasty, but may require valve replacement.[56] Hypertrophic cardiomyopathy may be treated by beta-blockade or calcium channel blockade, but occasionally requires surgical myomectomy.[56][57]

Cardiac care should continue into adulthood, as there can be ongoing morbidity and mortality associated with the defects.[30][56]

Plus – recombinant growth hormone

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ACUTE
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all patients
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with poor growth
Plus – 

recombinant growth hormone

Treatment recommended for ALL patients in selected patient group

Children with documented poor growth should be referred to an endocrinologist.

The treatment of young children (≤5 years of age) with growth hormone (GH) has been reported to have greater growth optimization, but risks and benefits of comorbidities such as hypertrophic cardiomyopathy and scoliosis must be considered.[70]

Studies of GH treatment in Noonan syndrome report height gains of 5 inches (13 cm) for males.[67][68][69] One study demonstrated near-adult height gains of up to 6 inches (15 cm) in patients treated for an average of 5 years (mean starting age of 11.6 years).[70] The duration of prepubertal treatment was an important contributor to change in height, suggesting greater growth potential with earlier treatment initiation.[70][67] Treatment effect is monitored by the growth response and insulin-like growth factor 1 (IGF-1) levels. Pathogenic variants in the PTPN11 gene have been associated with reduced growth response to GH in NS.[25][15][71][72] However, other studies report that response to GH therapy does not differ significantly according to genotype.[73][74][75][76] Large prospective studies are required to determine whether genotype influences response to GH therapy.

Primary options

somatropin (recombinant): consult specialist for guidance on dose

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Choose a patient group to see our recommendations

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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