Melanoma and LEOPARD Syndrome: Understanding the Role of PTPN11 Mutations in Melanomagenesis

Abstract is missing (Short communication)

Natural History of Hypertrophic Cardiomyopathy in Noonan Syndrome With Multiple Lentigines

BACKGROUND

We aimed to examine clinical features and outcomes of consecutive molecularly characterized patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy.

METHODS

A retrospective, longitudinal multicenter cohort of consecutive children and adults with a genetic diagnosis of Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy between 2002 and 2019 was assembled. We defined a priori 3 different patterns of left ventricular remodeling during follow-up: (1) an increase in ≥15% of the maximal left ventricular wall thickness (MLVWT), both in mm and z-score (progression); (2) a reduction ≥15% of the MLVWT, both in mm and z-score (absolute regression); (3) a reduction ≥15% of the MLVWT z-score with a stable MLVWT in mm (relative regression). The primary study end point was a composite of cardiovascular death, heart transplantation, and appropriate implantable cardioverter defibrillator-shock.

RESULTS

The cohort comprised 42 patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy, with a median age at diagnosis of 3.5 (interquartile range, 0.2-12.3) years. Freedom from primary end point was 92.7% (95% CI, 84.7%-100%) 1 year after presentation and 80.9% (95% CI, 70.1%-90.7%) at 5 years. Patients with MLVWT z-score >13.7 showed reduced survival compared with those with <13.7. During a median follow-up of 3.7 years (interquartile range, 2.6-7.9), absolute regression was the most common type of left ventricular remodeling (n=9, 31%), followed by progression (n=6, 21%), and relative regression (n=6, 21%).

CONCLUSIONS

These findings provide insights into the natural history of left ventricular hypertrophy, and can help inform clinicians regarding risk stratification and clinical outcomes in patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy.

[Overlap syndrome. LEOPARD and neurofibromatosis. A case report]

We expose a clinical case of a 43-year-old patient who was attended at the Dermatology service in a general hospital of the Instituto Mexicano del Seguro Social, with a disseminated pattern of lentigines, psychomotor retardation and electrocardiographic abnormalities. Afterwards, we made an analysis of the literature.

Do you know this syndrome? Leopard syndrome

Hypertrophic cardiomyopathy is known as Leopard syndrome, which is a mnemonic rule for multiple lentigines (L), electrocardiographic conduction abnormalities (E), ocular hypertelorism (O), pulmonary stenosis (P), abnormalities of genitalia (A), retardation of growth (R), and deafness (D). We report the case of a 12-year-old patient with some of the abovementioned characteristics: hypertelorism, macroglossia, lentigines, hypospadias, cryptorchidism, subaortic stenosis, growth retardation, and hearing impairment. Due to this set of symptoms, we diagnosed Leopard syndrome.

LEOPARD Syndrome

LEOPARD syndrome (LS) is an autosomal dominantly inherited or sporadic disorder of variable penetrance and expressivity. The acronym LEOPARD stands for its cardinal clinical features including Lentigines, Electrocardiographic conduction abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormalities of genitalia, Retardation of growth, and Deafness. We present herein a patient with LEOPARD syndrome and distinctive features. It was noteworthy that our patient presented with the concern of generalized lentiginosis and subsequent evaluation revealed that the patient had LEOPARD syndrome. In this report we would like to highlight the importance of detailed clinical examination and appropriate imaging in patients with multiple lentigines.

Generalized lentiginosis in an 11 year old boy

Generalized lentiginosis refers to generalized lentigines without systemic abnormalities, characterized by multiple brown or black macules owing to increased proliferation of melanocytes. There are also lentiginosis syndromes associated with systemic abnormalities such as Peutz-Jeghers syndrome, Leopard syndrome, and Carney complex. Generalized lentiginosis can be diagnosis by patient's history, physical and laboratory examination, and histopathology. We report an 11-year-old boy who presented with multiple dark brown macules, varying in size, but less than 0.5 cm, with no abnormalities of other systemic organs.

A rare cause of dyspnoea: the LEOPARD syndrome

The LEOPARD syndrome is a rare hereditary disorder in Asian countries. This syndrome involves complex malformations and other features. Though the LEOPARD syndrome is rare, diagnosis is important since it can be related with serious cardiac ailments. Patients must be followed up regularly in order to reduce the risk of sudden death which is the most severe complication. The study presents the case of a 23-year-old woman who had dyspnoea on daily exercises. She had multiple lentigines, cardiac anomalies (apical hypertrophic cardiomyopathy, left ventricular hypertrophy and pulmonary stenosis), ocular hypertelorism and abnormal electrocardiographic findings. Based on the findings, the patient was diagnosed with the LEOPARD syndrome.

Two cases of LEOPARD syndrome--RAF1 mutations firstly described in children

. LEOPARD syndrome 2 (LS-2) (OMIM #611554) is a rare, dominantly inherited genetic disorder affecting multiple organ systems. We report two unrelated females of different ages whose phenotype fits best in the category of LEOPARD syndrome, both with proven mutations in the RAF1 gene not previouslyreported in pediatric patients. In our 10-year-old patient, who was negative in the PTPN11 gene analysis but involving the RAF1 gene in a complementary analysis, the sequence variant Ser257Leu (770C > T, exon 7) was detected, which previously had been reported in only one 35-year-old woman with LS. The second patient was a two-year-old female infant with Ser259Leu mutation in the same gene, described in several patients with Noonan syndrome (NS) but not in LS patients of any age. The first girl had ventricular and supraventricular extrasystoles, and the second had episodes of paroxysmal supraventricular tachycardia. Echocardiographic examination revealed biventricular obstructive hypertrophic cardiomyopathy in both patients.

LEOPARD syndrome (PTPN11, T468M) in three boys fulfilling neurofibromatosis type 1 clinical criteria

Noonan syndrome (NS) and neurofibromatosis type 1 (NF1) are well-defined entities. The association of both disorders is called neurofibromatosis-Noonan syndrome (NFNS), a disorder that has been related to mutations in the NF1 gene. Both NS and NFNS display phenotypic overlapping with LEOPARD syndrome (LS), and differential diagnosis between these two entities often represents a challenge for clinicians. We report on three patients (two brothers and a not-related patient) diagnosed as having NFNS. They fulfilled NF1 diagnostic criteria and had some features of NS. The three of them had hypertophic cardiomyopathy while neurofibromas, Lisch nodules, and unidentified bright objects on MRI were absent. PTPN11 gene assays revealed a T468M mutation, typical of LS. Thorough clinical examinations of the patients revealed multiple lentigines, which were considered to be freckling in the initial evaluation. We conclude that NF1 clinical criteria should be used with caution in patients with features of NS. Patients with hyperpigmented cutaneous spots associated with cardiac anomalies, even if fulfilling the minimal NF1 criteria for diagnosis, should be strongly considered for LS diagnosis.

Noonan syndrome and clinically related disorders

Noonan syndrome is a relatively common, clinically variable developmental disorder. Cardinal features include postnatally reduced growth, distinctive facial dysmorphism, congenital heart defects and hypertrophic cardiomyopathy, variable cognitive deficit and skeletal, ectodermal and hematologic anomalies. Noonan syndrome is transmitted as an autosomal dominant trait, and is genetically heterogeneous. So far, heterozygous mutations in nine genes (PTPN11, SOS1, KRAS, NRAS, RAF1, BRAF, SHOC2, MEK1 and CBL) have been documented to underlie this disorder or clinically related phenotypes. Based on these recent discoveries, the diagnosis can now be confirmed molecularly in approximately 75% of affected individuals. Affected genes encode for proteins participating in the RAS-mitogen-activated protein kinases (MAPK) signal transduction pathway, which is implicated in several developmental processes controlling morphology determination, organogenesis, synaptic plasticity and growth. Here, we provide an overview of clinical aspects of this disorder and closely related conditions, the molecular mechanisms underlying pathogenesis, and major genotype-phenotype correlations.

[LEOPARD syndrome]

We describe a 12-year-old boy with a typical phenotype of the LEOPARD syndrome (LS). The diagnosis was confirmed in the boy and his mother, who both had a mutation in the PTPN11 gene at Thr468Met (c.1403C > T). Several other members of the maternal family are suspected also to have the LEOPARD syndrome. We discuss the clinical characteristics of LS, the need for follow-up and genetic counselling, and the molecular-genetic background as well as the relationship to the allelic disease Noonan syndrome.

[Lentigines in different multiple organ defects syndromes]

The aim of our study is to introduce a larger number of doctors to the subject of lentigines. They may be a first syndrome coexistent with very rare multiple organ defects as syndrome Peutz-Jeghers, LEOPARD, LAMB and Carney syndrome.

Leopard syndrome

The L.E.O.P.A.R.D. syndrome is an autosomal, dominant disorder with characteristic features that include: multiple lentigines, café au lait spots, electrocardiographic conduction abnormalities, ocular hypertelorism, obstructive cardiomyopathy, pulmonary stenosis, abnormal (male) genitalia, retardation of growth, and deafness. Patients do not usually present all the clinical features traditionally associated with the disorder. Indeed, several features are not present until late in life and do not become clinically manifest until puberty. It has been observed that this syndrome is caused by a "missense" mutation in PTPN11, a gene encoding the protein tyrosine phosphatase SHP-2 located on chromosome 12q22. A diagnosis of LEOPARD syndrome may be established exclusively on the basis of clinical criteria. In our case, the patient was diagnosed with the syndrome late in his life when he was already exhibiting all its distinctive clinical features. We have reported the case of a LEOPARD syndrome patient exhibiting extremely elongated vertebral and basilar arteries previously undescribed in the literature.

Severe cerebral calcification in a case of LEOPARD syndrome

We report severe brain calcification in a case of LEOPARD syndrome that has not been reported in the literature. A 53-year-old Japanese man presented with generalized lentigines, arrhythmia, gonadal hypoplasia, endocrine abnormality, mental retardation and skeletal abnormalities, and was consequently diagnosed as LEOPARD syndrome. Brain computed tomography demonstrated surprisingly dense and symmetric calcifications in the cerebellar dentate nuclei, cerebral basal ganglia, thalamus, and cerebral white matter. It may be an incidental idiopathic calcification. Alternatively it may be a rare clinical manifestation of LEOPARD syndrome.

Prevalence and clinical significance of cardiovascular abnormalities in patients with the LEOPARD syndrome

The aim of this study was to characterize cardiovascular involvement in a large number of patients with LEOPARD syndrome. Twenty-six patients (age range 0 to 63 years, median age at the time of the study evaluation 17 years) underwent clinical and genetic investigations. Familial disease was ascertained in 9 patients. Nineteen patients (73%) showed electrocardiographic abnormalities. Left ventricular (LV) hypertrophy was present in 19 patients (73%), including 9 with LV outflow tract obstructions; right ventricular hypertrophy was present in 8 patients (30%). Valve (57%) and coronary artery (15%) anomalies were also observed. Single patients showed LV apical aneurysm, LV noncompaction, isolated LV dilation, and atrioventricular canal defect. During follow-up (9.1 +/- 4.5 years), 2 patients died suddenly, and 2 patients had cardiac arrest. These patients had LV hypertrophy. Despite the limited number of subjects studied, genotype-phenotype correlations were observed in familial cases. In conclusion, most patients with LEOPARD syndrome showed LV hypertrophy, often in association with other valvular or congenital defects. A spectrum of underrecognized cardiac anomalies were also observed. Long-term prognosis was benign, but the occurrence of 4 fatal events in patients with LV hypertrophy indicates that such patients require careful risk assessment and, in some cases, consideration for prophylaxis against sudden death.

PTPN11 gene analysis in 74 Brazilian patients with Noonan syndrome or Noonan-like phenotype

Mutations in the PTPN11 gene are known to cause a large fraction of the cases of Noonan syndrome. The objective of this study was to determine the PTPN11 gene mutation rate in a cohort of clinically well-characterized Brazilian patients with Noonan or Noonan-like syndromes and to study the genotype-phenotype correlation. Fifty probands with Noonan syndrome ascertained according to well-established diagnostic criteria, 3 with LEOPARD syndrome, 5 with Noonan-like/multiple giant cell lesion syndrome, and 3 with neurofibromatosis/ Noonan were enrolled in this study. Mutational analysis was performed using denaturing high-performance liquid chromatography (DHPLC) followed by sequencing of amplicons with an aberrant elution profile. We detected missense mutations in the PTPN11 gene in 21 probands with Noonan syndrome (42%), in all 3 patients with LEOPARD syndrome, and in 1 case with Noonan-like/multiple giant cell lesion syndrome. One patient with neurofibromatosis-Noonan syndrome had a mutation in both the PTPN11 and NF1 genes. The only anomalies that reached statistical significance when comparing probands with and without mutations were the hematological abnormalities. Our data confirms that Noonan syndrome is a genetically heterogeneous disorder, with mutations in the PTPN11 gene responsible for roughly 50% of the cases. A definitive genotype-phenotype correlation has not been established, but the T73I mutation seems to predispose to a myeloproliferative disorder. Regarding Noonan-like syndromes, mutation of the PTPN11 gene is the main causal factor in LEOPARD syndrome, and it also plays a role in neurofibromatosis-Noonan syndrome. Noonan- like/multiple giant cell lesion syndrome, part of the spectrum of Noonan syndrome, is also heterogeneous.

PTPN11 gene mutations: linking the Gln510Glu mutation to the "LEOPARD syndrome phenotype"

We describe the "LEOPARD syndrome (LS) phenotype" associated with the Gln510Glu mutation of the PTPN11 gene in two patients presenting with rapidly progressive severe biventricular obstructive hypertrophic cardiomyopathy and structural abnormalities of the mitral valve, facial anomalies, café-au-lait spots and multiple lentigines.

LEOPARD syndrome: clinical diagnosis in the first year of life

LEOPARD syndrome (LS) is an autosomal dominant syndrome characterized by multiple lentigines and café-au-lait spots, electrocardiographic-conduction abnormalities, ocular hypertelorism/obstructive cardiomyopathy, pulmonary stenosis, abnormalities of the genitalia in males, retardation of growth, and deafness. LS shares many features with Noonan syndrome (NS), in which lentigines and deafness are usually not present. Molecular studies have shown that LS and NS are allelic disorders, caused by different missense mutations in PTPN11, a gene encoding the protein tyrosine phosphatase SHP-2 located at chromosome 12q22-qter. The clinical diagnosis of LS is generally difficult in the first months of life because the distinctive lentigines are generally not present at birth and develop during childhood. From January 2002 to December 2004, we suspected LS clinically in 10 patients admitted to our genetic counseling services in the first 12 months of life. A PTPN11 gene mutation was detected in 8/10 (80%) patients. In one patient without a PTPN11 mutation a subsequent clinical diagnosis of neurofibromatosis type 1 (NF1) was made, following the evaluation of the mother, who had previously undiagnosed classic NF1. The age of LS patients with PTPN11 mutation ranged between 1 and 11 months (mean age +/- SD 7.5 +/- 3.96 months). Review of the clinical characteristics of patients with LS confirmed by molecular study during the first year of life demonstrates that the diagnosis of LS in the first months of age can be clinically suspected in patients presenting with three main features, that is, characteristic facial features (100%), hypertrophic cardiomyopathy (HCM) (87%), and cafe-au-lait spots (75%). Characteristic facial features can be mild or severe, and consist of hypertelorism, downslanting palpebral fissures, ptosis, and dysmorphic ears. The clinical suspicion of LS may be confirmed by molecular screening for PTPN11 mutations. An early diagnosis of the disease is useful for the prospective care of associated medical problems and for precise genetic counseling.

Innenohrschwerhörigkeit beim LEOPARD-Syndrom

The rare multiple lentigines (LEOPARD) syndrome represents a complex of skin, cardiac, skeletal, inner ear and other malformations. There is marked variability in expression of the syndrome. We report on a 20 year old man, showing typical lentiginosis, a retardation of growth, tachycardiac conduction abnormality, ophthalmologic manifestations and a sensorineural hearing loss. Pathogenesis, clinical and differential diagnostic aspects are discussed in this case report. The early diagnosis of a senosorineural hearing loss is useful in order to provide appropriate rehabilitation. When lentiginosis is diagnosed, it is important to consider further abnormalities such as cardiomyopathy, which can be associated with a high mortality.

Familial aggregation of genetically heterogeneous hypertrophic cardiomyopathy: a boy with LEOPARD syndrome due to PTPN11 mutation and his nonsyndromic father lacking PTPN11 mutations

BACKGROUND

Nonsyndromic hypertrophic cardiomyopathy (HCM) is a primary cardiac disease transmitted as an autosomal dominant trait. Multiple chromosomal loci have been found to be involved in the etiology of this defect. LEOPARD syndrome is a genetic condition characteristically associated with HCM. Additional features of the syndrome include multiple lentigines, facial anomalies, sensorineural deafness, and growth retardation. Mutations in PTPN11, a gene encoding the protein tyrosine phosphatase SHP-2 located at chromosome 12q24, have been identified in patients with LEOPARD syndrome.

CASES

We report here on a patient with HCM presenting with classic clinical features of LEOPARD syndrome, whose father also has HCM, but lacks phenotypic anomalies of the syndrome. Molecular analysis searching for PTPN11 mutations was performed in this family. A missense mutation (836A-->G; Tyr279Cys) in exon 7 of PTPN11 gene was identified in the patient with LEOPARD syndrome, whereas no mutation in PTPN11 gene was detected in the father or in additional family members.

CONCLUSIONS

Aggregation of syndromic and nonsyndromic HCM in the same family is an unusual pattern of recurrence. Although genetic heterogeneity of LEOPARD and nonsyndromic HCM is not disputed, the existence of peculiar interactions linking genes causing nonsyndromic HCM and HCM in LEOPARD syndrome can be hypothesized. Different genes can work together, and a more severe cardiac phenotype can be due to additive effects. The involvement of familial susceptibility to specific cardiac malformations based on the presence of common predisposing factors can also be considered. Further molecular studies may shed light on these observations.