Noonan syndrome with multiple lentigines
Noonan syndrome with multiple lentigines, previously known as LEOPARD syndrome (LS), is a rare autosomal dominant RASopathy that has many similarities to Noonan syndrome.
Clinical presentation
Despite a change in formal name, the 'LEOPARD' acronym is still useful to summarize the clinical features:
- L: lentigines (multiple)
- E: ECG conduction abnormalities
- O: ocular hypertelorism
- P: pulmonary stenosis
- A: abnormal genitals
- R: retardation of growth
- D: deafness (sensorineural)
Importantly, this acronym does not include the other craniofacial anomalies (in addition to hypertelorism) which are identical to those of Noonan syndrome and present in nearly all patients .
Pathology
Genetics
Thought to result from a mutation in the PTPN11 (protein tyrosinephosphatase nonreceptor type 11) gene located on chromosome 12q24.1 , which results in increased signaling of the Ras/MAPK pathway. Thus, the disorder is classified as a RASopathy .
Associations
Complications
One concerning potential complication is the development of hypertrophic cardiomyopathy (HCM) (often in infancy) related to congenital cardiac defects.
History and etymology
Originally described by R J Gorlin and his colleagues in 1969 .