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This is a case report of a classical presentation of the Leopard syndrome from the Indian subcontinent. The male patient had progressively increasing generalised multiple lentiginosis, ocular hypertelorism, pulmonary stenosis, short stature, cryptorchidism, and pectus excavatum. The case is documented for its rarity in this part of the world and typical clinical presentation.
We observed dermal Merkel cells around vellus hair follicles in one patient with nevus of Ota and one with leopard syndrome. These Merkel cells were in contact with Schwann cells and nerve endings in the dermis. The question of whether or not Merkel cells exist normally in adult dermis remains unanswered. However, their presence in these abnormal conditions suggests that normally they do occur in the dermis but go undetected because their numbers are so few or they are in a form not readily identifiable by currently available methods.
We report a case of a 27-year-old woman with Leopard syndrome in which we observed the association of hypertrophic obstructive cardiomyopathy with arteriovenous cerebral shunt. This association has not been reported previously in the literature.
A man aged 32 years was referred to a dermatological department for alopecia areata. In addition, the patient had multiple lentigines which, together with other abnormalities, suggested the leopard syndrome. Alopecia areata does not appear to have been described previously in this syndrome.
LEOPARD (LS) and Noonan (NS) are overlapping syndromes associated with distinct mutations of SHP-2. Whereas NS mutations enhance SHP-2 catalytic activity, we show that the activity of three representative LS mutants is undetectable when assayed using a standard protein tyrosine phosphatase (PTP) substrate. A different assay using a specific SHP-2 substrate confirms their decreased PTP activity, but also reveals a significant activity of the T468M mutant. In transfected cells stimulated with epidermal growth factor, the least active LS mutants promote Gab1/PI3K binding, validating our in vitro data. LS mutants thus display a reduced PTP activity both in vitro and in transfected cells.
Antiarrhythmic agents can cause pneumonitis. Flecainide is a rare cause of hypersensitivity pneumonitis, and few cases have been reported. We describe a case of interstitial hypoxaemiant pneumonitis probably related to flecainide in a patient with the LEOPARD syndrome, a rare congenital disorder.
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The multiple lentigines/LEOPARD syndrome (ML/LS) is a rare and complex genetic syndrome. It is an autosomal dominant disorder with a variable expressivity. The syndrome is mainly characterised by growth retardation, multiple lentigines, and congenital heart diseases with electrocardiographic anomalies, dysmorphia of the face and deafness. The incidence of this pathology is still unknown and a familial inheritance is present in 70% of cases. Some of the ML/LS clinical features are the same as those of the Noonan syndrome (NS), such as congenital cardiac abnormalities, dysmorphia and growth retardation. NS and ML/LS are caused by allele mutations of the PTPN11 gene. We report the case of a 3-year-old girl, who was observed for the presence of widespread lentigines, a 1/6-protosystolic murmur at the mesocardium and growth retardation. The diagnosis of ML/LS was made and thus a molecular analysis of the PTPN11 gene was carried out, directly sequencing the codifying region. The molecular analysis revealed a missense mutation (A836G) in hexone 7 (TYR279CYS) of the PTPNII gene. This mutation is has been observed, at present, in a few cases of ML/LS and Noonan syndrome.
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Multiple lentigines/LEOPARD syndrome (LS) is a rare, autosomal dominant disorder characterized by Lentigines, Electrocardiogram abnormalities, Ocular hypertelorism, Pulmonic valvular stenosis, Abnormalities of genitalia, Retardation of growth, and Deafness. Like the more common Noonan syndrome (NS), LS is caused by germ line missense mutations in PTPN11, encoding the protein-tyrosine phosphatase Shp2. Enzymologic, structural, cell biological, and mouse genetic studies indicate that NS is caused by gain-of-function PTPN11 mutations. Because NS and LS share several features, LS has been viewed as an NS variant. We examined a panel of LS mutants, including the two most common alleles. Surprisingly, we found that in marked contrast to NS, LS mutants are catalytically defective and act as dominant negative mutations that interfere with growth factor/Erk-mitogen-activated protein kinase-mediated signaling. Molecular modeling and biochemical studies suggest that LS mutations contort the Shp2 catalytic domain and result in open, inactive forms of Shp2. Our results establish that the pathogenesis of LS and NS is distinct and suggest that these disorders should be distinguished by mutational analysis rather than clinical presentation.
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