1873
Refers to a constellation of multiple systemic findings with a prominent cutaneous component.
Classified as a member of the neuro-cardio-facial-cutaneous group that consists of Noonan syndrome, neurofibromatosis type 1, Costello syndrome, and cardiofaciocutaneous syndrome.
Main features include: Lentigines, electrocardiogram conduction abnormalities, occular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and sensorineural deafness.
Criteria for diagnosis include: multiple lentigines +2 of the cardinal features, or in the absence of the lentigines, three of the cardinal features plus a 1st° relative with the diagnosis.
Inherited as an autosomal dominant or a sporadic mutation that most frequently is a missense mutation of PTPN11.
In the small percentage of cases negative for PTPN11 mutation, RAF1 mutations have been identified.
Usually the lentigines are first identified at approximately age 4 to 5 years and increase in number until puberty.
The lentigines may eventually reach thousands in numbers.
Lentigines are frequently diffuse in nature but are usually concentrated on the upper half of the body and exclude the mucosa.
Additional skin findings that may be encountered include: café au lait spots, Café noir spots and epidermal nevi.
The most significant anomaly is cardiac involvement which frequently manifests as EKG conduction abnormalities, hypertrophic cardiomyopathy or pulmonary stenosis.
About 75% of patients have EKG abnormalities with ventricular hypertrophy as the most common abnormality.
Pulmonary stenosis is seen in 10-20% of patients.
Cardiomyopathy most frequently involves the left ventricle and is frequently asymptomatic.