Genotypic Findings in Noonan and Non-Noonan RASopathies and Patient Eligibility for Growth Hormone Treatment.

Molecular study has become an invaluable tool in the field of RASopathies. Treatment with recombinant human growth hormone is approved in Noonan syndrome but not in the other RASopathies. The aim of this study was to learn about the molecular base of a large cohort of patients with RASopathies, with particular emphasis on patients with pathogenic variants in genes other than PTPN11, and its potential impact on rGH treatment indication. We reviewed the clinical diagnosis and molecular findings in 451 patients with a genetically confirmed RASopathy. HRAS alterations were detected in only 2 out of 19 patients referred with a Costello syndrome suspicion, whereas pathogenic variants in RAF1 and SHOC2 were detected in 3 and 2, respectively. In 22 patients referred with a generic suspicion of RASopathy, including cardiofaciocutaneous syndrome, pathogenic alterations in classic Noonan syndrome genes (PTPN11, SOS1, RAF1, LZTR1, and RIT1) were found in 7 patients and pathogenic variants in genes associated with other RASopathies (HRAS, SHOC2, and PPPCB1) in 4. The correct nosological classification of patients with RASopathies is critical to decide whether they are candidates for treatment with rhGH. Our data illustrate the complexity of differential diagnosis in RASopathies, as well as the importance of genetic testing to guide the diagnostic orientation in these patients.

Truncating FLNC Mutations Are Associated With High-Risk Dilated and Arrhythmogenic Cardiomyopathies.

BACKGROUND: Filamin C (encoded by the FLNC gene) is essential for sarcomere attachment to the plasmatic membrane. FLNC mutations have been associated with myofibrillar myopathies, and cardiac involvement has been reported in some carriers. Accordingly, since 2012, the authors have included FLNC in the genetic screening of patients with inherited cardiomyopathies and sudden death. OBJECTIVES: The aim of this study was to demonstrate the association between truncating mutations in FLNC and the development of high-risk dilated and arrhythmogenic cardiomyopathies. METHODS: FLNC was studied using next-generation sequencing in 2,877 patients with inherited cardiovascular diseases. A characteristic phenotype was identified in probands with truncating mutations in FLNC. Clinical and genetic evaluation of 28 affected families was performed. Localization of filamin C in cardiac tissue was analyzed in patients with truncating FLNC mutations using immunohistochemistry. RESULTS: Twenty-three truncating mutations were identified in 28 probands previously diagnosed with dilated, arrhythmogenic, or restrictive cardiomyopathies. Truncating FLNC mutations were absent in patients with other phenotypes, including 1,078 patients with hypertrophic cardiomyopathy. Fifty-four mutation carriers were identified among 121 screened relatives. The phenotype consisted of left ventricular dilation (68%), systolic dysfunction (46%), and myocardial fibrosis (67%); inferolateral negative T waves and low QRS voltages on electrocardiography (33%); ventricular arrhythmias (82%); and frequent sudden cardiac death (40 cases in 21 of 28 families). Clinical skeletal myopathy was not observed. Penetrance was >97% in carriers older than 40 years. Truncating mutations in FLNC cosegregated with this phenotype with a dominant inheritance pattern (combined logarithm of the odds score: 9.5). Immunohistochemical staining of myocardial tissue showed no abnormal filamin C aggregates in patients with truncating FLNC mutations. CONCLUSIONS: Truncating mutations in FLNC caused an overlapping phenotype of dilated and left-dominant arrhythmogenic cardiomyopathies complicated by frequent premature sudden death. Prompt implantation of a cardiac defibrillator should be considered in affected patients harboring truncating mutations in FLNC.

Síndrome LEOPARD: una variante del síndrome de Noonan con fuerte asociación a miocardiopatía hipertrófica / LEOPARD syndrome: a variant of noonan syndrome strongly associated with hypertrophic cardiomyopathy

Introducción y objetivos. El síndrome LEOPARD es una enfermedad autosómica dominante relacionada con el síndrome de Noonan, aunque menos conocida. El objetivo del presente estudio es describir las características clínicas y moleculares de una serie amplia de pacientes con síndrome LEOPARD. Métodos. Se obtuvieron datos clínicos de 19 pacientes procedentes de 10 hospitales. Se estudiaron los genes PTPN11, RAF1 y BRAF mediante secuenciación bidireccional de los exones más recurrentes. Resultados. Tras las dismorfias faciales, la principal característica descrita es la cardiopatía congénita (88%). La más frecuente es la miocardiopatía hipertrófica (71%), por delante de la estenosis pulmonar (35%). Se describió lentiginosis múltiple o manchas café con leche en un 84% y sordera en 3 pacientes; 16 pacientes (84%) portaban mutación en PTPN11 (en 10 de ellos, la mutación recurrente en el síndrome LEOPARD, p.Thr468Met) (NP_002825.3). En otros 2 pacientes se identificó mutación en RAF1 y 1 solo en BRAF. En comparación con otros síndromes neurocardiofaciocutáneos, los pacientes con LEOPARD tienen mayor prevalencia de miocardiopatía hipertrófica y lesiones cutáneas y menor prevalencia de estenosis pulmonar y talla baja. Conclusiones. El síndrome LEOPARD presenta algunas características distintivas además de la lentiginosis múltiple, como son la mayor frecuencia de miocardiopatia hipertrófica y menor prevalencia de talla baja. Dadas las potenciales implicaciones clínicas de la miocardiopatía hipertrófica, se debe buscar activamente en los pacientes del espectro clínico del síndrome de Noonan, y muy especialmente en aquellos con síndrome LEOPARD (AU)

Introduction and objectives. LEOPARD syndrome is an autosomal dominant condition related to Noonan syndrome, although it occurs less frequently. The aim of this study was to characterize the clinical and molecular features of a large series of LEOPARD syndrome patients. Methods. We collected clinical data from 19 patients in 10 hospitals. Bidirectional sequencing analysis of PTPN11, RAF1, and BRAF focused on exons carrying recurrent mutations. Results. After facial dysmorphism, structural heart defects (88%) were the most common feature described. Hypertrophic cardiomyopathy (71%) was diagnosed more often than pulmonary valve stenosis (35%). Multiple lentigines or café au lait spots were found in 84% of the series, and deafness was diagnosed in 3 patients. Mutations in PTPN11 were identified in 16 (84%) patients (10 patients had the recurrent LEOPARD syndrome mutation, p.Thr468Met) (NP_002825.3T468M). Two other patients had a mutation in RAF, and 1 patient had a mutation in BRAF. When compared with other neurocardiofaciocutaneous syndromes, LEOPARD syndrome patients showed a higher prevalence of hypertrophic cardiomyopathy and cutaneous abnormalities, and a lower prevalence of pulmonary valve stenosis and short stature. Conclusions. LEOPARD syndrome patients display distinctive features apart from multiple lentigines, such as a higher prevalence of hypertrophic cardiomyopathy and lower prevalence of short stature. Given its clinical implications, active search for hypertrophic cardiomyopathy is warranted in Noonan syndrome spectrum patients, especially in LEOPARD syndrome patients (AU)

LEOPARD syndrome: a variant of Noonan syndrome strongly associated with hypertrophic cardiomyopathy.

INTRODUCTION AND OBJECTIVES: LEOPARD syndrome is an autosomal dominant condition related to Noonan syndrome, although it occurs less frequently. The aim of this study was to characterize the clinical and molecular features of a large series of LEOPARD syndrome patients. METHODS: We collected clinical data from 19 patients in 10 hospitals. Bidirectional sequencing analysis of PTPN11, RAF1, and BRAF focused on exons carrying recurrent mutations. RESULTS: After facial dysmorphism, structural heart defects (88%) were the most common feature described. Hypertrophic cardiomyopathy (71%) was diagnosed more often than pulmonary valve stenosis (35%). Multiple lentigines or café au lait spots were found in 84% of the series, and deafness was diagnosed in 3 patients. Mutations in PTPN11 were identified in 16 (84%) patients (10 patients had the recurrent LEOPARD syndrome mutation, p.Thr468Met) (NP_002825.3T468M). Two other patients had a mutation in RAF, and 1 patient had a mutation in BRAF. When compared with other neurocardiofaciocutaneous syndromes, LEOPARD syndrome patients showed a higher prevalence of hypertrophic cardiomyopathy and cutaneous abnormalities, and a lower prevalence of pulmonary valve stenosis and short stature. CONCLUSIONS: LEOPARD syndrome patients display distinctive features apart from multiple lentigines, such as a higher prevalence of hypertrophic cardiomyopathy and lower prevalence of short stature. Given its clinical implications, active search for hypertrophic cardiomyopathy is warranted in Noonan syndrome spectrum patients, especially in LEOPARD syndrome patients.

Alteraciones de los genes de la vía RAS-MAPK en 200 pacientes españoles con síndrome de Noonan y otros síndromes neurocardiofaciocutáneos. Genotipo y cardiopatía / Alterations in RAS-MAPK genes in 200 spanish patients with noonan and other neuro-cardio-facio-cutaneous syndromes. Genotype and cardiopathy

Introducción y objetivos. La caracterización molecular de cardiopatías incluye una entidad congénita no infrecuente, el síndrome de Noonan. Presentamos el estudio de seis genes de la vía RAS-MAPK en pacientes españoles: perfil genotípico, impacto de la cardiopatía y expresividad clínica. Métodos. Compusieron la población en estudio 643 pacientes (y 182 familiares) diagnosticados por dismorfólogos, cardiólogos y endocrinopediatras de 74 hospitales (11 comunidades). Estudio primario de PTPN11 y complementario de SOS1, RAF1, BRAF, KRAS y HRAS, estratificado y orientado por signos clínicos, mediante secuenciación de exones recurrentes (un 80-95% de mutaciones descritas). Resultados. Se documentó mutación en 230 pacientes (91 mujeres, 139 varones) de 200 familias (31%), 172 PTPN11 +, 14 SOS1 +, 9 RAF1 + y 5 BRAF +, con referencia explícita a la cardiopatía padecida en 156 casos índice; 103 presentaban estenosis de la válvula pulmonar; 12, estenosis de la válvula pulmonar y miocardiopatía hipertrófica; 18, miocardiopatía hipertrófica y 14, otra cardiopatía; en sólo 9 casos se encontraba ausente. En 23/30 familiares positivos no había o no constaba cardiopatía. El rendimiento diagnóstico fue superior (p = 0,016) para las muestras de algunos centros (53%; 14/32), y alcanzó el 64% (9/14; p = 0,019) en profesionales concretos. El rendimiento cayó al 18% en los pacientes sin datos clínicos facilitados. El dato genotípico reorientó el diagnóstico clínico en 26 pacientes. Conclusiones. El 94% de los pacientes portadores de mutación presentaban cardiopatía, el 79% estenosis de la válvula pulmonar y el 12% miocardiopatía hipertrófica. En el 76% de los familiares positivos con rasgos clínicos compatibles, no se había documentado la cardiopatía. El estudio molecular es una herramienta útil en estos síndromes, aunque debe progresarse en la objetivación del diagnóstico clínico (AU)

Introduction and objectives. Molecular characterization of congenital heart diseases now includes the not infrequent dysmorphic Noonan syndrome. A study of 6 genes of the RAS-MAPK pathway in Spanish patients is presented: the impact of heart disease, clinical expressivity, and diagnostic yield are investigated. Methods. The study included 643 patients (and 182 family members) diagnosed by dysmorphologists, cardiologists, and pediatric endocrinologists from 74 tertiary hospitals. Bidirectional sequencing analysis of PTPN11, SOS1, RAF1, BRAF, KRAS and HRAS focused on exons carrying recurrent mutations accounting for 80% to 95% of previously described mutations. Results. Mutations were detected in 230 patients (91 women and 139 men) in 200 (31%) families (172 PTPN11+, 14 SOS1+, 9 RAF1+, 5 BRAF+). There was specific reference to the heart defect suffered in 156 index cases: 103 patients had shown pulmonary stenosis, 12 pulmonary stenosis with hyperthrophic cardiomyopathy, 18 hypertrophic cardiomiopathy, and 14 other cardiopathies; heart disease was absent in 9 index cases. Heart disease had not been documented in 23 of 30 family members with positive genotype and compatible clinical signs. Diagnostic yield was higher (P=.016) for samples from some centers (53%; 14/32) and even from certain professionals (64%; 9/14; P=.019). Characterization rate was 18% in patients for whom clinical data were not available. Genotyping led to a more precise diagnosis in 26 patients. Conclusions. Most patients (94%) with a positive genotype had known congenital heart disease, 79% pulmonary stenosis and 12% hyperthrophic cardiomyopathy. Cardiopathy had not been documented in 76% of family members carrying the mutation. Molecular study is a useful tool in these syndromes but a more rigorous clinical diagnosis should be intended as well (AU)

Alterations in RAS-MAPK genes in 200 Spanish patients with Noonan and other neuro-cardio-facio-cutaneous syndromes. Genotype and cardiopathy.

INTRODUCTION AND OBJECTIVES: Molecular characterization of congenital heart diseases now includes the not infrequent dysmorphic Noonan syndrome. A study of 6 genes of the RAS-MAPK pathway in Spanish patients is presented: the impact of heart disease, clinical expressivity, and diagnostic yield are investigated. METHODS: The study included 643 patients (and 182 family members) diagnosed by dysmorphologists, cardiologists, and pediatric endocrinologists from 74 tertiary hospitals. Bidirectional sequencing analysis of PTPN11, SOS1, RAF1, BRAF, KRAS and HRAS focused on exons carrying recurrent mutations accounting for 80% to 95% of previously described mutations. RESULTS: Mutations were detected in 230 patients (91 women and 139 men) in 200 (31%) families (172 PTPN11+, 14 SOS1+, 9 RAF1+, 5 BRAF+). There was specific reference to the heart defect suffered in 156 index cases: 103 patients had shown pulmonary stenosis, 12 pulmonary stenosis with hyperthrophic cardiomyopathy, 18 hypertrophic cardiomiopathy, and 14 other cardiopathies; heart disease was absent in 9 index cases. Heart disease had not been documented in 23 of 30 family members with positive genotype and compatible clinical signs. Diagnostic yield was higher (P=.016) for samples from some centers (53%; 14/32) and even from certain professionals (64%; 9/14; P=.019). Characterization rate was 18% in patients for whom clinical data were not available. Genotyping led to a more precise diagnosis in 26 patients. CONCLUSIONS: Most patients (94%) with a positive genotype had known congenital heart disease, 79% pulmonary stenosis and 12% hyperthrophic cardiomyopathy. Cardiopathy had not been documented in 76% of family members carrying the mutation. Molecular study is a useful tool in these syndromes but a more rigorous clinical diagnosis should be intended as well.