Definition

Noonan syndrome with multiple lentigines (NSML) is a rare inherited disorder. People with this condition have problems with the skin, head and face, inner ear, and heart. The genitals may also be affected.

Noonan syndrome with multiple lentigines was formerly known as LEOPARD syndrome.

Alternative Names

Multiple lentigines syndrome; LEOPARD syndrome; NSML

Causes

NSML is inherited as an autosomal dominant trait. This means the person only needs an abnormal gene from one parent in order to inherit the disorder.

Symptoms

The former name of NSML of LEOPARD stands for the different problems (signs and symptoms) of this disorder:

• Lentigines -- large number of brown or black freckle-like skin markings that mainly affect the neck and upper chest but can appear all over the body
• Electrocardiograph conduction abnormalities -- problems with the electrical and pumping functions of the heart
• Ocular hypertelorism -- eyes that are spaced wide apart
• Pulmonary valve stenosis -- narrowing of the pulmonary heart valve, resulting in less blood flow to the lungs and causing shortness of breath
• Abnormalities of the genitals -- such as undescended testicles
• Retardation of growth (delayed growth) -- including bone growth problems of the chest and spine
• Deafness -- hearing loss may vary between mild and severe

NSML is similar to Noonan syndrome. However, the main symptom that tells apart the two conditions is that people with NSML have lentigines.

Exams and Tests

Your health care provider will perform a physical exam and listen to the heart with a stethoscope. 

Tests that may be done include:

• Electrocardiogram (ECG) and echocardiogram to check the heart
• Hearing test
• CT scan of the brain
• Skull x-ray
• EEG to check the brain's function
• Blood tests to check certain hormone levels
• Removing a small amount of skin for examination (skin biopsy)

Treatment

Symptoms are treated as appropriate. A hearing aid may be needed. Hormone treatment may be necessary at the expected time of puberty to cause the normal changes to occur.

Laser, cryosurgery (freezing), or bleaching creams may help lighten some of the brown spots on the skin.

Support Groups

More information and support for people with LEOPARD syndrome and their families can be found at:

• National Organization for Rare Disorders - rarediseases.org/rare-diseases/leopard-syndrome/
• Noonan Syndrome Foundation - www.teamnoonan.org/information
• Rasopathies Network - rasopathiesnet.org/

Possible Complications

Complications vary and include:

• Deafness
• Delayed puberty
• Heart problems
• Infertility

When to Contact a Medical Professional

Contact your provider if there are symptoms of this disorder.

Contact your provider for an appointment if you have a family history of this disorder and plan to have children.

Prevention

Genetic counseling is recommended for people with a family history of NSLM who want to have children.

References

James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM. Melanocytic nevi and neoplasms. In: James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM, eds. Andrews' Diseases of the Skin: Clinical Dermatology. 13th ed. Philadelphia, PA: Elsevier; 2020:chap 30.

Paller AS, Mancini AJ. Disorders of pigmentation. In: Paller AS, Mancini AJ, eds. Paller and Mancini – Hurwitz Clinical Pediatric Dermatology. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 11.