Diagnostic Criteria

Suggested clinical diagnostic criteria for Noonan syndrome with multiple lentigines (NSML) have been published .

Suggestive Findings

NSML should be suspected in individuals with one or more of the following cardinal features:

• Lentigines

• Cardiac abnormalities, particularly hypertrophic cardiomyopathy

• Poor linear growth / short stature

• Pectus deformity

• Dysmorphic facial features including widely spaced eyes and ptosis

Additional features occurring frequently in NSML:

• Variable degree of cognitive deficits

• Sensorineural hearing loss

• Cryptorchidism

• Skeletal anomalies

• Caf au lait macules

• Family history consistent with autosomal dominant inheritance (e.g., affected males and females in multiple generations)

Note: Absence of a known family history does not preclude the diagnosis.

Source: GeneReviews — "Noonan Syndrome with Multiple Lentigines"

Differential Diagnosis

Noonan syndrome with multiple lentigines (NSML) should be distinguished from Turner syndrome, Williams syndrome, and monogenic disorders with developmental delay, short stature, congenital heart defects, and distinctive facies . Turner syndrome, found only in females, is distinguished from NSML by demonstration of an X-chromosome abnormality on cytogenetic studies. The characteristic facial features are also distinct, and in Turner syndrome renal anomalies are more common, developmental delay is much less frequently found, and left-sided heart defects are the rule. Williams syndrome and NSML are relatively distinct, as they are associated with different facial features, cardiovascular involvement, skin features, and neurodevelopmental profiles.

Source: GeneReviews — "Noonan Syndrome with Multiple Lentigines"

Management Guidelines

No clinical practice guidelines for Noonan syndrome with multiple lentigines (NSML) have been published. Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with NSML, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 5. Recommended Evaluations Following Initial Diagnosis in Individuals with Noonan Syndrome with Multiple Lentigines

Source: GeneReviews — "Noonan Syndrome with Multiple Lentigines"

Clinical Guidance

For individuals with hypertrophic cardiomyopathy:

• Treatment with growth hormone must be undertaken with great caution – if at all – to avoid exacerbating a cardiac condition;

• Certain physical activities may be curtailed in order to reduce the risk of sudden cardiac death.

Source: GeneReviews — "Noonan Syndrome with Multiple Lentigines"

Therapies Under Investigation

Search Clinical Trials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "Noonan Syndrome with Multiple Lentigines"

Surveillance Guidelines

Table 7. Recommended Surveillance for Individuals with Noonan Syndrome with Multiple Lentigines

Source: GeneReviews — "Noonan Syndrome with Multiple Lentigines"