Frequency of aortic dilation in Noonan syndrome

Genetic aortopathies: a case-based approach to multidisciplinary program development

PURPOSE OF REVIEW

The incorporation of genetic counseling and testing is essential to evaluation and management of thoracic aortic disease in patients under 60 years of age and those with family histories suspicious for heritable thoracic aortic disease and disorders associated with increased risk for acute type-A aortic dissection.

RECENT FINDINGS

As many as 20% of individuals with thoracic aortic disease under the age of 60 years have autosomal dominant patterns of inheritance. A considerable number of heritability factors remain undefined for these families.

SUMMARY

Genetic aortopathy programs require a collaborative approach including cardiovascular specialists and surgeons, medical geneticists, genetic counselors, and allied healthcare professionals. Comprehensive evaluation and management of these patients includes collection of detailed phenotypic data to inform the broader community and identify new associated and causative genes of interest, genetic modifiers, and other risk factors. These programs optimize outcomes and reduce the overall burden in the population of acute aortic dissection and related comorbidities.

Retained primary teeth: A clinical complaint not to be dismissed

Retained primary teeth (RPT) may be an isolated finding, or one associated with other clinical complaints. In order to achieve timely and accurate diagnosis, it is helpful for paediatricians to perform thorough work-up for these patients. The article aims at providing an overview of the inborn medical causes that may be related to children with RPT, as well as their corresponding investigation and treatment modalities.

Clinical Variability in a Family with Noonan Syndrome with a Homozygous PTPN11 Gene Variant in Two Individuals

Objective

Noonan syndrome (NS) is characterized by dysmorphic facial features, short stature, congenital heart defects, and varying levels of developmental delays. It is a genetic, multisystem disorder with autosomal dominant inheritance and is the most common of the RASopathies. In approximately 50% of patients, NS is caused by variants in the Protein Tyrosine Phosphatase Non-Receptor Type 11 (PTPN11) gene. The aim of this study was to evaluate two patients with a previously reported PTPN11 homozygous variant for the first time and seven other kindred members carrying the same heterozygous variant in terms of clinical, biochemical, genetic, and response to treatment.

Methods

Nine patients diagnosed with NS due to the same variants in the PTPN11 gene were included in the study.

Results

The median (range) age at diagnosis was 11.5 (6.8-13.9) years and the mean follow-up duration was 4.7 (1-7.6) years. In eight patients (88.9%), short stature was present. The height standard deviation score of the patients on admission was -3.24±1.15. In six of the patients, growth hormone treatment was initiated. Cardiovascular or bleeding disorders were not detected in any of the patients. Three (33.3%) had hearing loss, two (22.2%) had ocular findings and one (11.1%) had a horseshoe kidney. The mean psychomotor development performance score was 84.03±17.09 and the verbal score was 82.88±9.42. Genetic analysis revealed a variant in the PTPN11 gene [c.772G>A; (p.Glu258Lys)] that had been previously described and was detected in all patients. Two patients were homozygous for this variant and short stature was more severe in these two.

Conclusion

A previously described in PTPN11 affected nine members of the same kindred, two with homozygous inheritance and the remainder being heterozygous. To the best of our knowledge, these are the first homozygous PTPN11 case reports published, coming from two related consanguineous families.

Rare Congenital Dissecting Thoracic Aortic Aneurysm in a Child with Noonan Syndrome: A Case Report

We present a rare case of congenital thoracic aortic aneurysm (TAA) complicated with dissection in a nine-year-old girl with Noonan syndrome and atrial septal defect. She presented with rapid breathing and upper respiratory tract symptoms. Chest X-ray revealed a huge upper mediastinum with cardiomegaly. Echocardiogram showed possible ascending TAA. Computerized tomography angiogram of the aorta revealed huge aortic root-ascending TAA with small aortic dissection. Despite immediate treatment, the patient passed away due to severe airway compromise.

The heart in RASopathies

The cardiovascular phenotype associated with RASopathies has expanded far beyond the original descriptions of pulmonary valve stenosis by Dr Jaqueline Noonan in 1968 and hypertrophic cardiomyopathy by Hirsch et al. in 1975. Because of the common underlying RAS/MAPK pathway dysregulation, RASopathy syndromes usually present with a typical spectrum of overlapping cardiovascular anomalies, although less common cardiac defects can occur. The identification of the causative genetic variants has enabled the recognition of specific correlations between genotype and cardiac phenotype. Characterization and understanding of genotype-phenotype associations is not only important for counseling a family of an infant with a new diagnosis of a RASopathy condition but is also critical for their clinical prognosis with respect to cardiac disease, neurodevelopment and other organ system involvement over the lifetime of the patient. This review will focus on the cardiac manifestations of the most common RASopathy syndromes, the relationship between cardiac defects and causal genetic variation, the contribution of cardiovascular abnormalities to morbidity and mortality and the most relevant follow-up issues for patients affected by RAS/MAPK pathway diseases, with respect to cardiac clinical outcomes and management, in children and in the adult population.

Third reported patient with RAP1B-related syndromic thrombocytopenia and novel clinical findings

RAP1B is a RAS-superfamily small GTP-binding protein involved in numerous cell processes. Pathogenic gain-of-function variants in this gene have been associated with RAP1B-related syndromic thrombocytopenia, an ultrarare disorder characterized by hematologic abnormalities, neurodevelopmental delays, growth delay, and congenital birth defects including cardiovascular, genitourinary, neurologic, and skeletal systems. We report a 23-year-old male with a novel, de novo RAP1B gain-of-function variant identified on genome sequencing. This is the third reported case which expands the molecular and phenotypic spectrum of RAP1B-related syndromic thrombocytopenia.

Long-Term Effectiveness and Safety of Childhood Growth Hormone Treatment in Noonan Syndrome

INTRODUCTION

Few data exist on long-term growth hormone (GH) treatment in patients with Noonan syndrome (NS).

OBJECTIVE

To evaluate the effectiveness and safety of GH treatment in NS in clinical practice.

METHODS

Height gain, near-adult height (NAH), and safety were assessed in 2 complementary non-interventional studies: NordiNet® IOS and ANSWER. The safety analysis included 412 patients, and the effectiveness analysis included 84 GH-treated patients (male, n = 67) with ≥4 years' height standard deviation score (HSDS) data. HSDS was determined using national reference (NR) and NS-specific (NSS) data.

RESULTS

The mean (SD) baseline age was 8.38 (3.57) years; HSDS, -2.76 (1.03); GH dose, 41.6 (11.1) µg/kg/day. The mean (SD) HSDS increase from baseline (ΔHSDS) was 0.49 (0.37) (first year), 0.79 (0.58) (second year), and 1.01 (0.60) (third year) (NR). The mean (SD) HSDS at year 3 was -1.66 (1.00) (NR; 1.06 [1.12] [NSS]). Twenty-four patients achieved NAH. The mean (SD) NAH SDS (NR) was -1.51 (0.60) (154.90 [3.21] cm) in females and -1.79 (1.09) (165.61 [7.19] cm) in males; 70.8% (17/24) had NAH SDS ≥ -2. Adverse drug reactions and GH-unrelated serious adverse events (n = 34) were reported in 22/412 (5.3%) patients. Four neoplasms and 3 cases of scoliosis were reported; no cardiovascular adverse events occurred.

CONCLUSIONS

GH-treated children with NS achieved substantial height gain during the first 3 years of follow-up. Overall, 24 patients achieved NAH, with 70.8% having NAH SDS ≥ -2. There was no evidence to support a higher prevalence of neoplasm, or cardiac or other comorbidities.

Coronary artery disease in adults with Noonan syndrome: Case series and literature review

Noonan syndrome (NS) is a genetic disorder characterized by facial dysmorphism, congenital heart disease, and short stature. In very rare cases, patients with this syndrome have coronary disease. Their management and prognosis are currently unclear. We have described 4 cases of coronary aneurysms/coronary ectasia and 1 case of a single coronary artery in patients with adult Noonan syndrome, followed in a medical and surgical center of adult congenital heart disease. The average age was 49.4years old. The majority of them had both pulmonary stenosis and interauricular communication. None had symptoms of angina, at rest, or with stress. Only one patient who had any structural heart disease, had a thrombotic complication with chronic occlusion of the right coronary and anterior inter ventricular artery, fortuitous finding, with no ischemic signs to functional tests, treated only with anti-vitamin K. Finally, any deaths have also been reported in our series. Coronary artery diseases essentially coronary aneurysm/ectasia remain a rare condition in adult patients with NS. Evolution is unknown and complications such as coronary artery thrombosis do not necessarily require surgical treatment.

Prevalence and Clinical Correlates of Aortic Dilation in Hypertrophic Cardiomyopathy

BACKGROUND

Aortic dilation has been associated with various cardiac conditions, although its prevalence and clinical correlates in hypertrophic cardiomyopathy (HCM) remain unclear.

OBJECTIVES

The purposes of this study were to define the prevalence of ascending aortic dilation in a large referral population of patients with HCM and to determine clinical and echocardiographic correlates of aortic dilation.

METHODS

A total of 1,698 patients with HCM underwent echocardiographic measurement of the tubular ascending aorta (proximal and midlevel) during index evaluation at a tertiary HCM referral center. End-diastolic ascending aorta dimension was indexed to body surface area, with dilation defined for the tubular ascending aorta as 2 SD above the mean (>19 mm/m²) and independently as greater than published age-, sex-, and body surface area- adjusted norms (for the sinus of Valsalva and midlevel). Aortic size and presence of aortic enlargement were correlated with clinical and echocardiographic parameters.

RESULTS

Tubular ascending aortic dilation >19 mm/m² was present in 303 patients with HCM (18%), and dilation above adjusted norms was present in 210 patients with HCM (13%). The median indexed tubular ascending thoracic aortic dimension was 16.5 (interquartile range, 14.8-18.2) mm/m². Indexed dimension increased linearly with age (R = 0.53, P < .0001). Women and patients with a history of systemic hypertension were more likely to have tubular aortic enlargement >19 mm/m² (29.8% vs 9.9% and 24.1% vs 10.5%, respectively, P < .0001 for both). Patients with obstructive physiology were more likely to have tubular aortic enlargement >19 mm/m² than those without resting or provocable obstruction (19.6% vs 14.4%, P = .007). Using adjusted norms, aortic enlargement was more frequent at the midlevel compared with the sinus of Valsalva (71% vs 29%), more common in patients with hypertension (15.4% vs 10.6%, P = .009), and more common in patients with paroxysmal atrial fibrillation (16.3% vs 11.5%, P = .036), but no other relationships remained statistically significant.

CONCLUSIONS

In this large cohort of patients with HCM, aortic dilation was common. The key correlate of tubular aortic enlargement >19 mm/m², and aortic enlargement greater than adjusted norms included a history of systemic hypertension. Given an increased prevalence of aortic dilation in HCM, further study is needed on the clinical impact of aortic dilation.

Congenital heart defects in Noonan syndrome: Diagnosis, management, and treatment

Noonan syndrome is a pleomorphic genetic disorder, in which a high percentage of affected individuals have cardiovascular involvement, most prevalently various forms of congenital heart disease (i.e., pulmonary valve stenosis, septal defects, left-sided lesions, and complex forms with multiple anomalies). Care includes attentiveness to several comorbidities, some directly impacting cardiac management (bleeding diatheses and lymphatic anomalies). More than 50% of patients with Noonan syndrome harbor PTPN11 pathogenic variation, which results in hyperactivation of RAS/mitogen-activated protein kinase signaling. Several other disease genes with similar biological effects have been uncovered for NS and phenotypically related disorders, collectively called the RASopathies. Molecular diagnosis with gene resequencing panels is now widely available, but phenotype variability and in some cases, subtlety, continues to make identification of Noonan syndrome difficult. Until genetic testing becomes universal for patients with congenital heart disease, alertness to Noonan syndrome's broad clinical presentations remains crucial. Genotype-phenotype associations for Noonan syndrome enable better prognostication for affected patients when a molecular diagnosis is established. We still lack Noonan syndrome-specific treatment; however, newly developed anticancer RAS pathway inhibitors could fill that gap if safety and efficacy can be established for indications such as pulmonary valve stenosis.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Cardiovascular disease in Noonan syndrome

PURPOSE OF REVIEW

To provide information on the scope of cardiac disease in Noonan syndrome.

RECENT FINDINGS

Noonan syndrome is a common autosomal dominant RASopathy disorder characterized by clinical findings of facial dysmorphism, congenital heart disease, and short stature. The degree of genetic heterogeneity has recently become evident in that Noonan syndrome is now known to be caused by mutations in a large variety of genes which produce dysregulation of the RAS-MAPK (mitogen-activated protein kinase) signaling pathway. The scope of cardiac disease in Noonan syndrome is quite variable depending on the gene mutation, with some mutations usually associated with a high incidence of congenital heart defects (PTPN11, KRAS, and others) while those with predominantly hypertrophic cardiomyopathy (HCM) have higher risk and morbidity profiles (RAF1, RIT1, and those associated with multiple lentigines).

SUMMARY

Cardiac disease in Noonan syndrome varies according to the type of gene mutation. The most common forms of cardiac disease include pulmonary stenosis, HCM, and atrial septal defect. HCM in general is associated with increased risk, mortality, and morbidity. New concepts for potential treatments are discussed.

Clinical Presentation and Natural History of Hypertrophic Cardiomyopathy in RASopathies

RASopathies are a heterogeneous group of genetic syndromes characterized by mutations in genes that regulate cellular processes, including proliferation, differentiation, survival, migration, and metabolism. Excluding congenital heart defects, hypertrophic cardiomyopathy is the most frequent cardiovascular defect in patients affected by RASopathies. A worse outcome (in terms of surgical risk and/or mortality) has been described in a specific subset of Rasopathy patients with early onset, severe hypertrophic cardiomyopathy presenting with heart failure. New short-term therapy with a mammalian target of rapamycin inhibitor has recently been used to prevent heart failure in these patients with a severe form of hypertrophic cardiomyopathy.

Developmental Changes in Aortic Mechanical Properties in Normal Fetuses and Fetuses with Cardiovascular Disease

BACKGROUND

We hypothesized that fetal aortic mechanical properties assessed by aortic diameter (AoD) and flow show maturational changes during the gestational period, and that these properties are different in fetuses with congenital heart diseases and fetuses with normal development.

METHODS

Phasic changes in ascending AoD along with Doppler flow profile were measured in 84 consecutive normal fetuses (gestational age, 18-36 weeks) and in 30 consecutive fetuses with cardiovascular diseases (gestational age, 22-39 weeks).

RESULTS

AoD and cardiac output significantly increased with gestational age. Fetal aortic compliance (AC), assessed as (maximum AoD - minimum AoD)/stroke volume, significantly decreased with gestational age in normal fetuses, indicating maturational changes in aortic wall properties. Importantly, fetuses with Marfan syndrome and tetralogy of Fallot that exhibit "aortopathy" showed significantly lower AC than normal fetuses of the same gestational age, suggesting intrinsic abnormalities in aortic wall properties in these diseases. Fetuses with trisomy 18 and Noonan syndrome also had AC values below the normal ranges.

CONCLUSION

Measurements of phasic changes in fetal AoD and flow measurements can provide useful information about aortic mechanical properties and may help clarify abnormal arterial hemodynamics in pathologic conditions.

Genetic and Epigenetic Regulation of Aortic Aneurysms

Aneurysms are characterized by structural deterioration of the vascular wall leading to progressive dilatation and, potentially, rupture of the aorta. While aortic aneurysms often remain clinically silent, the morbidity and mortality associated with aneurysm expansion and rupture are considerable. Over 13,000 deaths annually in the United States are attributable to aortic aneurysm rupture with less than 1 in 3 persons with aortic aneurysm rupture surviving to surgical intervention. Environmental and epidemiologic risk factors including smoking, male gender, hypertension, older age, dyslipidemia, atherosclerosis, and family history are highly associated with abdominal aortic aneurysms, while heritable genetic mutations are commonly associated with aneurysms of the thoracic aorta. Similar to other forms of cardiovascular disease, family history, genetic variation, and heritable mutations modify the risk of aortic aneurysm formation and provide mechanistic insight into the pathogenesis of human aortic aneurysms. This review will examine the relationship between heritable genetic and epigenetic influences on thoracic and abdominal aortic aneurysm formation and rupture.

Aortic dilation, genetic testing, and associated diagnoses

PURPOSE

The aims of this study were to determine the genetic diagnoses most frequently associated with aortic dilation in a large population and to describe the results of genetic testing in the same.

METHODS

A retrospective review of records from patients with known aortic dilation identified through an echocardiogram database was performed. During the study period, different chromosomal microarray platforms and molecular diagnostic techniques were used.

RESULTS

A total of 715 patients (mean age, 9.7 years; 67% male) met study inclusion criteria. The overall frequency of underlying presumptive or confirmed genetic diagnoses was 17% (125/715). Molecular evaluation for possible underlying aortopathy-related disorders was performed in 9% of patients (66/715). Next-generation sequencing panels were performed in 16 patients, and pathogenic abnormalities were detected in 4 (25%). Microarrays were conducted in 10% of patients (72/715), with a total of 23 pathogenic copy-number variants identified in 19 patients (26%). Marfan syndrome was the most frequently recognized genetic disorder associated with aortic dilation, but other cytogenetic abnormalities and associated diagnoses also were identified.

CONCLUSION

The differential diagnosis in patients with aortic dilation is broad and includes many conditions outside the common connective tissue disorder spectrum. A genetics evaluation should be considered to assist in the diagnostic evaluation.Genet Med 18 4, 356-363.