LEOPARD syndrome with recurrent PTPN11 mutation Y279C and different cutaneous manifestations: two case reports and a review of the literature.

LEOPARD syndrome (LS) is a heterogeneous disease characterised mainly by cutaneous manifestations. LEOPARD is the acronym for its major features-multiple lentigines, electrocardiographic conduction defects, ocular hypertelorism, pulmonary stenosis, abnormalities of (male) genitalia, retardation of growth and sensorineural deafness. As clinical manifestations are variable, molecular testing is supportive in the diagnosis of LS. We describe two unrelated LS cases with a common PTPN11 mutation Y279C and with completely different clinical features including distinct changes in skin pigmentation. In patient 1, the first complaint was hyperactive behaviour. First lentigines were presented at birth, but intensive growth began at the age of 2-4 years. Multiple dark lentigines were located mainly on the face and the upper part of the trunk, but the oral mucosa was spared. Patient 2 was born from induced labour due to polyhydramnion, and in the second week of life, mitral valve insufficiency and hypertrophic cardiomyopathy were diagnosed. Rapid growth of lentigines began at the age of 3 years. These are mostly located in the joint areas in the lower extremities; the face and upper trunk are spared from lentigines. In both cases, the rapid growth of lentigines made it possible to shift the diagnosis towards LS. Clinicians should give more consideration to rare genetic syndromes, especially in the case of symptoms from different clinical areas.