LEOPARD Syndrome with PTPN11 Gene Mutation in Three Family Members Presenting with Different Phenotypes.
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ABSTRACT:
SUBMITTER: Alfurayh N
PROVIDER: S-EPMC7396475 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:LEOPARD syndrome (LS) is an acronym consisting of lentigines, electrocardiographic abnormalities, ocular hypertelorism, pulmonary valve stenosis, abnormal genitalia, retardation of growth and deafness. However, hypertrophic cardiomyopathy, the most frequent cause of sudden cardiac death in young people, is the most common cardiovascular manifestation in LS patients and the major determinant of mortality and morbidity. In approximately 85% of the patients with a definite diagnosis of LS, a missense mutation is found in the protein-tyrosine phosphatase non-receptor type 11 (PTPN11) gene located on chromosome 12q24.1. We report the case of an asymptomatic 17-year-old male with a missense mutation (c.836A>G) in exon 7 (Tyr279Cys) of the PTPN11 gene and a non-obstructive asymmetric anteroseptal hypertrophic cardiomyopathy.
| S-EPMC3362168 | biostudies-literature
Project description:LEOPARD syndrome (LS) is an autosomal dominant "RASopathy" that manifests with congenital heart disease. Nearly all cases of LS are caused by catalytically inactivating mutations in the protein tyrosine phosphatase (PTP), non-receptor type 11 (PTPN11) gene that encodes the SH2 domain-containing PTP-2 (SHP2). RASopathies typically affect components of the RAS/MAPK pathway, yet it remains unclear how PTPN11 mutations alter cellular signaling to produce LS phenotypes. We therefore generated knockin mice harboring the Ptpn11 mutation Y279C, one of the most common LS alleles. Ptpn11(Y279C/+) (LS/+) mice recapitulated the human disorder, with short stature, craniofacial dysmorphia, and morphologic, histologic, echocardiographic, and molecular evidence of hypertrophic cardiomyopathy (HCM). Heart and/or cardiomyocyte lysates from LS/+ mice showed enhanced binding of Shp2 to Irs1, decreased Shp2 catalytic activity, and abrogated agonist-evoked Erk/Mapk signaling. LS/+ mice also exhibited increased basal and agonist-induced Akt and mTor activity. The cardiac defects in LS/+ mice were completely reversed by treatment with rapamycin, an inhibitor of mTOR. Our results demonstrate that LS mutations have dominant-negative effects in vivo, identify enhanced mTOR activity as critical for causing LS-associated HCM, and suggest that TOR inhibitors be considered for treatment of HCM in LS patients.
| S-EPMC3049377 | biostudies-literature
Project description:ObjectiveTo analyze the clinical data and genetic characteristics of Noonan syndrome, both the effect and side effects of recombinant human growth hormone (rhGH) treatment.MethodsWe collected clinical data from 8 children with Noonan syndrome diagnosed from November 2017 to June 2021. The diagnosis was clarified by exome second-generation sequencing and parental PCR-NGS validation and interpretation of the preceding evidence, and growth hormone therapy was administered. Of the cases, four males and four females were seen for slow height growth and the median age at diagnosis was 8 years 7 months (1 year 7 months to 12 years 6 months).ResultsHere, 7 children were treated with rhGH. Compared to the pre-treatment period, the growth rate increased after rhGH treatment [3.7 ± 0.5 cm/year before treatment and 8.0 ± 1.0 cm/year after treatment, p < 0.01], with the maximum growth rate between 3 and 6 months of treatment and decreasing with the duration of treatment thereafter. The growth hormone treatment was discontinued and the orthopedic consultation was ordered with regular follow-up, which was considered to be related to the PTPN11 mutation.ConclusionNoonan syndrome is characterized by slow growth, short stature, mental retardation, peculiar facial features, structural heart abnormalities and abnormal bone metabolism. and osteochondroma was found after case 2 rhGH treatment. Genetic examination is mostly caused by PTPN11 mutation. It is recommended to pay attention to bone metabolism abnormalities before growth hormone treatment, especially in children with PTPN11 mutations.
| S-EPMC10655517 | biostudies-literature
Project description:The ubiquitous non-receptor protein tyrosine phosphatase SHP2 (encoded by PTPN11) plays a key role in RAS/ERK signaling downstream of most, if not all growth factors, cytokines and integrins, although its major substrates remain controversial. Mutations in PTPN11 lead to several distinct human diseases. Germ-line PTPN11 mutations cause about 50% of Noonan Syndrome (NS), which is among the most common autosomal dominant disorders. LEOPARD Syndrome (LS) is an acronym for its major syndromic manifestations: multiple Lentigines, Electrocardiographic abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormalities of genitalia, Retardation of growth, and sensorineural Deafness. Frequently, LS patients have hypertrophic cardiomyopathy, and they might also have an increased risk of neuroblastoma (NS) and acute myeloid leukemia (AML). Consistent with the distinct pathogenesis of NS and LS, different types of PTPN11 mutations cause these disorders.Although multiple studies have reported the biochemical and biological consequences of NS- and LS-associated PTPN11 mutations, their structural consequences have not been analyzed fully. Here we report the crystal structures of WT SHP2 and five NS/LS-associated SHP2 mutants. These findings enable direct structural comparisons of the local conformational changes caused by each mutation.Our structural analysis agrees with, and provides additional mechanistic insight into, the previously reported catalytic properties of these mutants. The results of our research provide new information regarding the structure-function relationship of this medically important target, and should serve as a solid foundation for structure-based drug discovery programs.
| S-EPMC4007598 | biostudies-literature
Project description:Missense mutations in the PTPN11 gene, which encodes the protein tyrosine phosphatase SHP-2, cause clinically similar but distinctive disorders, LEOPARD (LS) and Noonan (NS) syndromes. The LS is an autosomal dominant disorder with pleomorphic developmental abnormalities including lentigines, cardiac defects, short stature and deafness. Biochemical analyses indicated that LS alleles engender loss-of-function (LOF) effects, while NS mutations result in gain-of-function (GOF). These biochemical findings lead to an enigma that how PTPN11 mutations with opposite effects on function result in disorders that are so similar. To study the developmental effects of the commonest LS PTPN11 alleles (Y279C and T468M), we generated LS transgenic fruitflies using corkscrew (csw), the Drosophila orthologue of PTPN11. Ubiquitous expression of the LS csw mutant alleles resulted in ectopic wing veins and, for the Y279C allele, rough eyes with increased R7 photoreceptor numbers. These were GOF phenotypes mediated by increased RAS/MAPK signaling and requiring the LS mutant's residual phosphatase activity. Our findings provide the first evidence that LS mutant alleles have GOF developmental effects despite reduced phosphatase activity, providing a rationale for how PTPN11 mutations with GOF and LOF produce similar but distinctive syndromes.
| S-EPMC2644650 | biostudies-literature
Project description:In this review, we focus on elucidating the cardiac function of germline mutations in the PTPN11 gene, encoding the Src homology-2 (SH2) domain-containing protein tyrosine phosphatase SHP2. PTPN11 mutations cause LEOPARD syndrome (LS) and Noonan syndrome (NS), two disorders that are part of a newly classified family of autosomal dominant syndromes termed "RASopathies," which are caused by germline mutations in components of the RAS/RAF/MEK/ERK mitogen activating protein kinase pathway. LS and NS mutants have opposing biochemical properties, and yet, in patients, these mutations produce similar cardiac abnormalities. Precisely how LS and NS mutations lead to such similar disease etiology remains largely unknown. Recent complementary in vitro, ex vivo, and in vivo analyses reveal new insights into the functions of SHP2 in normal and pathological cardiac development. These findings also reveal the need for individualized therapeutic approaches in the treatment of patients with LS and NS and, more broadly, patients with the other "RASopathy" gene mutations as well.
| S-EPMC3372917 | biostudies-literature
Project description:Noonan syndrome (NS) is characterized by short stature, facial dysmorphisms and congenital heart defects. PTPN11 mutations are the most common cause of NS. Patients with NS have a predisposition for leukemia and certain solid tumors. Data on the incidence of malignancies in NS are lacking. Our objective was to estimate the cancer risk and spectrum in patients with NS carrying a PTPN11 mutation. In addition, we have investigated whether specific PTPN11 mutations result in an increased malignancy risk. We have performed a cohort study among 297 Dutch NS patients with a PTPN11 mutation (mean age 18 years). The cancer histories were collected from the referral forms for DNA diagnostics, and by consulting the Dutch national registry of pathology and the Netherlands Cancer Registry. The reported frequencies of cancer among NS patients were compared with the expected frequencies using population-based incidence rates. In total, 12 patients with NS developed a malignancy, providing a cumulative risk for developing cancer of 23% (95% confidence interval (CI), 8-38%) up to age 55 years, which represents a 3.5-fold (95% CI, 2.0-5.9) increased risk compared with that in the general population. Hematological malignancies occurred most frequently. Two malignancies, not previously observed in NS, were found: a malignant mastocytosis and malignant epithelioid angiosarcoma. No correlation was found between specific PTPN11 mutations and cancer occurrence. In conclusion, this study provides first evidence of an increased risk of cancer in patients with NS and a PTPN11 mutation, compared with that in the general population. Our data do not warrant specific cancer surveillance.
| S-EPMC3172922 | biostudies-literature
Project description:Multiple-lentigines (ML)/LEOPARD (multiple lentigines, electrocardiographic-conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and sensorineural deafness) syndrome is an autosomal dominant condition--characterized by lentigines and café au lait spots, facial anomalies, cardiac defects--that shares several clinical features with Noonan syndrome (NS). We screened nine patients with ML/LEOPARD syndrome (including a mother-daughter pair) and two children with NS who had multiple café au lait spots, for mutations in the NS gene, PTPN11, and found, in 10 of 11 patients, one of two new missense mutations, in exon 7 or exon 12. Both mutations affect the PTPN11 phosphotyrosine phosphatase domain, which is involved in <30% of the NS PTPN11 mutations. The study demonstrates that ML/LEOPARD syndrome and NS are allelic disorders. The detected mutations suggest that distinct molecular and pathogenetic mechanisms cause the peculiar cutaneous manifestations of the ML/LEOPARD-syndrome subtype of NS.
| S-EPMC379170 | biostudies-literature
Project description:LEOPARD syndrome (LS, OMIM 151100) is a rare multiple congenital anomalies condition, mainly characterized by skin, facial and cardiac anomalies. LEOPARD is an acronym for the major features of this disorder, including multiple Lentigines, ECG conduction abnormalities, Ocular hypertelorism, Pulmonic stenosis, Abnormal genitalia, Retardation of growth, and sensorineural Deafness. About 200 patients have been reported worldwide but the real incidence of LS has not been assessed. Facial dysmorphism includes ocular hypertelorism, palpebral ptosis and low-set ears. Stature is usually below the 25th centile. Cardiac defects, in particular hypertrophic cardiomyopathy mostly involving the left ventricle, and ECG anomalies are common. The lentigines may be congenital, although more frequently manifest by the age of 4-5 years and increase throughout puberty. Additional common features are café-au-lait spots (CLS), chest anomalies, cryptorchidism, delayed puberty, hypotonia, mild developmental delay, sensorineural deafness and learning difficulties. In about 85% of the cases, a heterozygous missense mutation is detected in exons 7, 12 or 13 of the PTPN11 gene. Recently, missense mutations in the RAF1 gene have been found in two out of six PTPN11-negative LS patients. Mutation analysis can be carried out on blood, chorionic villi and amniotic fluid samples. LS is largely overlapping Noonan syndrome and, during childhood, Neurofibromatosis type 1-Noonan syndrome. Diagnostic clues of LS are multiple lentigines and CLS, hypertrophic cardiomyopathy and deafness. Mutation-based differential diagnosis in patients with borderline clinical manifestations is warranted. LS is an autosomal dominant condition, with full penetrance and variable expressivity. If one parent is affected, a 50% recurrence risk is appropriate. LS should be suspected in foetuses with severe cardiac hypertrophy and prenatal DNA test may be performed. Clinical management should address growth and motor development and congenital anomalies, in particular cardiac defects that should be monitored annually. Hypertrophic cardiomyopathy needs careful risk assessment and prophylaxis against sudden death in patients at risk. Hearing should be evaluated annually until adulthood. With the only exception of ventricular hypertrophy, adults with LS do not require special medical care and long-term prognosis is favourable.
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Project description:Current clinical diagnosis of long-QT syndrome (LQTS) includes genetic testing of family members of mutation-positive patients. The present study was designed to assess the clinical course of individuals who are found negative for the LQTS-causing mutation in their families.Multivariate Cox proportional hazards model was used to assess the risk for cardiac events (comprising syncope, aborted cardiac arrest [ACA], or sudden cardiac death [SCD]) from birth through age 40 years among 1828 subjects from the LQTS Registry who were found negative for their family LQTS-causing mutation. The median QTc of study subjects was 423 ms (interquartile range, 402-442 ms). The cumulative probability of a first syncope through age 40 years was 15%. However, only 2 patients (0.1%) had ACA, and none died suddenly during follow-up. Independent risk factors for syncope in genotype-negative subjects included female sex (hazard ratio [HR], 1.60; P=0.002), prolonged QTc (HR=1.63 per 100 ms increment, P=0.02), family history of ACA or SCD (HR=1.89, P=0.002), and LQT2 versus LQT1 family mutation (HR=1.41, P=0.03). Subgroup analysis showed that the presence of the K897T polymorphism in the LQT2 gene in an affected family was associated with an 11-fold (P=0.001) increase in the risk of recurrent syncope in genotype-negative subjects.Our findings suggest that cardiac events among genotype-negative family members of LQTS patients are dominated by nonfatal syncopal episodes without occurrence of sudden cardiac death. The risk for nonfatal events in this population may be mediated by the presence of common polymorphisms in LQTS genes.
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