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10-6-03 NEW RESEARCH STUDY AT THE HARVARD PARTNERS CENTER FOR GENETICS AND GENOMICS (HPCGG)! Please contact Amy Roberts, MD 617-525-5768 or e-mail aeroberts@partners.org for additional information.
PARTNERS HUMAN RESEARCH COMMITTEE DETAILED PROTOCOL BACKGROUND AND SIGNIFICANCE
In 1883 Kobylinski was the first to report a patient with clinical features compatible with what is now called Noonan syndrome (NS). Early cases reported both males and females with the common features of a webbed neck, small stature with low set ears, and micrognathia. It was later determined that a subset of this group included females with pubertal delay. When karyotype analysis was developed, this subset was found to have a single copy of the X chromosome or what is now called Turner syndrome. Those remaining with normal chromosomes were labeled as having "Turner Phenotype". In 1963, Noonan and Ehmke reported nine patients- six males and three females with short stature and characteristic facies including hypertelorism, ptosis, low set ears, undescended testes, chest deformities, valvular pulmonary stenosis, and normal chromosome analysis. Soon after, the term "Turner Phenotype" was replaced with the eponym used today- Noonan Syndrome (Noonan, 1994). The incidence of Noonan syndrome has been estimated to be from one in 1000-2500 for severely affected individuals to one in 100 for mildly affected individuals (Mendez, 1985). There appears to be no racial predilection and cases have been reported worldwide. Among children with congenital heart disease, Noonan syndrome is one of the most common genetic syndromes. Noonan syndrome is considered an autosomal dominant disorder. There are a number of families with three generations of affected individuals. However, there is evidence for an autosomal recessive form of the disorder (van der Burgt, 2000). Because males with Noonan syndrome frequently have undescended testes and associated infertility problems, it is more common to observe mother to child transmission than father to child. Like other autosomal dominant disorders, there is extensive variability in expression. Also, the phenotype changes from childhood to adulthood. As a result, mildly affected adults are not always diagnosed or may be diagnosed in retrospect with the birth of a more severely affected child. In the newborn, Noonan syndrome is difficult to diagnose by facial appearance as features can be subtle. The forehead is often sloping and broad, ears thick and posteriorly rotated, or eyes widely spaced and down slanting. There may be a deep philtrum, recessed chin, or marked edema with excess nuchal skin. From infancy to age two, the head often appears relatively large with flat malar eminences, prominent and round eyes, depressed nasal bridge, and/or a short neck. In childhood, chest deformities become more prominent, coarse facial features and a triangular face develops, the eyes become less prominent, and ptosis may be seen. The neck appears longer and webbing and low hairline more obvious. In teenage and young adulthood, the triangular face is more prominent and the nose has a pinched root and thin, high bridge. The older adult has prominent nasolabial folds, a high anterior hairline, and transparent, wrinkled skin (Noonan 1994). Many children have mild motor delay and at least a third have some degree of
mental retardation or learning disabilities. Conductive hearing loss is
frequent. Common eye manifestations include hypertelorism, ptosis, epicanthal
folds, refractive errors, strabismus, amblyopia, and colobomas. Weight and
length are usually normal at birth but short stature is present in 80% with
height often less than weight (Noonan, 1994). Bone maturity is delayed at least
two years so active linear growth continues into the early twenties. The more
common potential orthopedic problems include chest deformity (pectus carinatum
or excavatum), scoliosis, and talipes equinovarus. Hypotonia is common and
generally improves over time. Over half of males diagnosed with Noonan syndrome
have unilateral or bilateral cryptorchidism. Reported associated neurologic
problems include recurrent seizures, peripheral neuropathy, spina bifida occulta,
subarachnoid hemorrhage from aneurysm, and syringomyelia. About half of patients
have a cardiac problem most commonly a dysplastic, often stenotic pulmonary
valve but virtually every type of cardiac defect has been described.
Hypertrophic cardiomyopathy occurs in 20-30% of patients and frequently involves
both the right and left ventricles. A variety of bleeding disorders have been
described in association with the syndrome including factor XI deficiency, Von
Willebrand's disease, thrombocytopenia, and platelet function defects. Lymphatic
abnormalities have been found in one fifth of patients (Noonan, 1994) From a genetic point of view, NS was a poorly understood condition until recently. Because of the superficial resemblance to patients with Turner syndrome, an abnormality of the X chromosome has been suspected. Because some patients meet the diagnostic criteria for neurofibromatosis type 1 and NS, it has been postulated that the genetic defect may be linked to the NF-1 locus on chromosome 17. There has been no evidence of an abnormality in either the X chromosome or chromosome 17 to date. A locus at chromosomal band 12q24 (NS1) was established in a study of two large families inheriting NS (Jamieson et al 1994, Brady et al 1997; Legius et al 1998). Genetic heterogeneity was also documented on the basis of linkage exclusion (Jamieson et al 1994). During studies of genetic interaction between Egfr encoding the epidermal growth factor receptor , and PTPN11 encoding the protein-tyrosine phosphatase SHP-2 (src homology region 2-domain phosphatase-2), Chen et al (2000) discovered that both Egfr and SHP-2 are components of a growth factor signaling pathway required for semilunar valvulogenesis. SHP-2 exists in an inactive or an active conformation, with the N-SH2 domain acting as a molecular switch. PTPN11 had previously been localized to 12q24.1-24.3 (Dechert 1995). Because of its localization and its role in valvulogenesis, PTPN11 was considered an excellent candidate gene for Noonan syndrome. Recently, PTPN11 was identified as the NS1 disease gene (Tartaglia et al 2001). This group (which included our Principal Investigator, Raju Kucherlapati PhD) first conducted mutation screening with two moderately sized families in which the NS phenotype cosegregated with particular haplotypes. The analysis was then done on 22 unrelated patients with NS (some sporadic, some familial) and mutations were found in 50% of individuals. The mutations cosegregated with the NS phenotype within the families and was not detected in any of the 200 control samples tested. The eight residues affected by NS-causing mutations are all located in and around the interactive surfaces of the N-SH2 PTP domains. An energetics based structural analysis of two of the mutations indicated that they may lead to a significant shift in equilibrium favoring the active conformation of SHP-2. Tartaglia (2002), again working with our Principal Investigator, Dr. Kucherlapati, recently published a study of the molecular spectrum, genotype-phenotype correlation, and phenotypic heterogeneity of PTPN11 mutations in a group of 119 unrelated patients with the clinical diagnosis of Noonan syndrome. Mutations were found in 54 patients (45%). There was a higher prevalence of mutations found among familial (59%) than sporadic (37%) cases of NS (P<.02). Several of the mutations detected were recurrent. As was seen in their prior study, the group found that the majority of mutations altered amino acid residues located in or around the interacting surfaces of the N-SH2 and PTP domains. Pulmonic stenosis was a more prevalent feature among those with a detectable mutation than among those without a detectable mutation (70.6% vs 46.2%, P<.01). Hypertrophic cardiomyopathy was less prevalent among those with detectable mutations than among those without detectable mutations (5.9% vs. 26.2%, P<.005). They found no difference between the two groups in the prevalence of other congenital heart defects, short stature, pectus deformity, cryptorchidism, or developmental delay. Kosaki et al (2002) examined twenty one patients with a clinical diagnosis of Noonan syndrome. PTPN11 mutations were found in one third of the patients. Three of the mutation positive patients had pulmonary valve disease, none had hypertrophic cardiomyopathy. Six of the fourteen mutation negative patients had "cardiac defects" not more specifically defined. One published abstract describes a small study that screened PTPN11 gene
mutations in 23 patients with non-syndromic, nondysplastic pulmonary valve
stenosis. None had a detectable mutation (Sarkozy 2002). Rationale behind the proposed research, and the potential benefits to patients and/or society 1. A more complete assessment of the range of PTPN11 lesions causing NS and related disorders The current estimate is that PTPN11 mutations account for approximately 50% of cases of Noonan syndrome. Studying more patients with a clinical diagnosis of Noonan syndrome will help to better define this prevalence. Additionally, different mutations may be described. Characterization of the mutations and their role in SHP-2 function will aid in understanding the pathogenesis of the Noonan syndrome phenotype. It is our hope that this will be applicable to other cardiac or craniofacial malformation models. There are advantages to patients who have a genotypic (vs a phenotypic diagnosis). Patients with detectable mutations will be counseled as to the 50% chance of recurrence with each of their children. Prenatal testing would be available. Affected children could be diagnosed prenatally or in infancy which would enable early evaluations for heart, skeletal, eye, hematologic, and developmental problems thus maximizing their potential for intervention and treatment. 2. Examination of genotype phenotype correlations As more patients are tested, particular mutation prevalences can be better estimated. The most common mutations can be compared phenotypically to look for clues in the role of the mutation in pathogenesis. Additionally, by phenotypically characterizing the group without a detectable mutation, comparisons can be made between the two groups (mutation negative and mutation positive) to look for phenotypic differences. This may help in developing pre-test probabilities for future testing. Detailed characterization of the mutation negative group may lead to further studies to look for additional candidate genes. 3. Evaluation of patients with "Noonan-like" phenotype who have some of the features of Noonan syndrome but do not meet strict diagnostic criteria. It is likely that a proportion of these patients will have PTPN11 mutations. The diagnostic criteria were developed from a series of significantly affected individuals. It is possible that by liberalizing the inclusion criteria and testing people who have some, but not all of the features of NS, more mildly affected patients with PTPN11 mutations will be identified. There are advantages to patients who have a genotypic (vs a phenotypic diagnosis). Patients with detectable mutations could be counseled as to the 50% chance of recurrence with each of their children. Prenatal testing would be available. Affected children could be diagnosed prenatally or in infancy which would enable early evaluations for heart, skeletal, eye, hematologic, and developmental problems thus maximizing their potential for intervention and treatment. 4. Further delineate the role of PTPN11 mutations in cardiac malformations and hypertrophic cardiomyopathy It is not uncommon for a gene responsible for a multiple anomaly syndrome to be associated with one of the sentinel defects occurring in isolation. There are children with pulmonic stenosis and hypertrophic cardiomyopathy who do not appear to have other features of Noonan syndrome. Examining these patients and testing them for PTPN11 mutations may broaden our understanding of the variability of expression in NS. There are advantages to patients who have a genotypic (vs. a purely
phenotypic diagnosis). Patients with detectable mutations could be counseled as
to the 50% chance of recurrence with each of their children. Prenatal testing
would be available. Affected children could be diagnosed prenatally or in
infancy which would enable early evaluations for heart, skeletal, eye,
hematologic, and developmental problems thus maximizing their potential for
intervention and treatment. SPECIFIC AIMS PRIMARY AIMS I. NOONAN SYNDROME HYPOTHESIS 1: Pulmonary valve disease is more prevalent among patients with Noonan syndrome and a PTPN11 mutation than among patients with Noonan syndrome without a PTPN11 mutation. HYPOTHESIS 2: Hypertrophic cardiomyopathy is less prevalent among patients with Noonan syndrome and a PTPN11 mutation than among patients with Noonan syndrome without a detectable PTPN11 mutation. B. COAGULATION OBJECTIVE: The prevalence and type of PTPN11 mutations among patients with Noonan syndrome and coagulation abnormalities will be estimated. C. GENITOURINARY ANOMALIES Over half of males with NS have one or both testes undescended. Tartaglia,
2002, found no statistically significant difference in the prevalence of
cryptorchidism in the PTPN11 mutation positive and negative groups. OBJECTIVE: The prevalence and type of PTPN11 mutations among patients with Noonan syndrome and renal abnormalities will be estimated. OBJECTIVE: The prevalence and type of PTPN11 mutations among patients with
Noonan syndrome and cryptorchidism will be estimated. II. CONGENITAL HEART DEFECTS AND PTPN11 A. PULMONARY VALVE DISEASE OBJECTIVE: The prevalence and type of PTPN11 mutations among patients with pulmonary valve disease, both dysplastic and non dysplastic will be estimated. B. HYPERTROPHIC CARDIOMYOPATHY OBJECTIVE: The prevalence and type of PTPN11 mutations among patients with
hypertrophic cardiomyopathy will be estimated. SECONDARY AIMS I. NOONAN-LIKE PHENOTYPE OBJECTIVE: The prevalence and type of PTPN11 mutations among patients who meet some but not all of the diagnostic criteria for Noonan syndrome and do not fit the diagnostic criteria for any other syndrome will be estimated. II. NOONAN SYNDROME GENOTYPE-PHENOTYPE ANALYSIS OBJECTIVE We will examine particular diagnostic criteria (typical facial features, congenital heart disease, renal malformation, or coagulopathy) with regard to mutation status to determine if any of the features are more prevalent in the mutation positive group than in the mutation negative group. Along similar lines, within the mutation positive group, we will determine if
a specific mutation is more or less likely to correlate with a particular
phenotypic feature. No prior studies have examined this question. SUBJECT SELECTION A. Clinical diagnosis of NS (Based on scoring system developed by van der
Burgt et al, 1994) B. Noonan-like Phenotype C. Isolated Pulmonary Valve Disease D. Isolated Cardiomyopathy E. Exclusion: Source of subjects and recruitment methods a. BWH/MGH and CH Genetics and Cardiology Staff: attending physicians will be
notified by letter (appended) about the study and inclusion criteria. They can
discuss the option of being part of a research study with appropriate patients
and refer those who are interested. SUBJECT ENROLLMENT b. Procedures for obtaining informed consent (including timing of consent
process) c. Treatment assignment, and randomization (if applicable) STUDY PROCEDURES b. Drugs to be used: NA Data to be collected and when the data is to be collected BIOSTATISTICAL ANALYSIS RISKS AND DISCOMFORTS Efforts will be made to eliminate as much as possible the inappropriate disclosure of personal information. The first efforts are standard efforts to maintain confidentiality. The second effort is to establish anonymity for patients who indicate this preference on their consent form. Identifying information will be separated from the clinical information questionnaire upon receipt in the research lab to establish confidentiality. The questionnaire will be labeled with a linking code unless the patient has requested anonymization (see below). As is standard in any testing lab, identifying information will be removed from the blood sample and it will be given an accession number to establish confidentiality. Patients who do not wish to have the results of their testing and who consent to storage of a DNA sample only if it is anonymized will have their blood sample and clinical information questionnaire anonymized with a code number without linking information. A copy of the consent form will be kept in a locked file at the Partners Laboratory of Molecular Medicine. For the non-anonymized samples, identifying information, linking confidentiality code lists, and a copy of the consent will be kept in a locked file cabinet at the Harvard Partners Laboratory for Molecular Medicine. Only the Principal Investigator and Co-Investigators will have access to this file. For the anonymized samples, consent forms will be kept in a separate file in a locked file cabinet at the Harvard Partners Laboratory for Molecular Medicine. Because the PTPN11 test is clinically available, the results will be entered into the patient's medical record (if the testing has been completed without anonymization). No information will be given to other family members without permission from the patient. A copy of the informed consent form will not be placed in the medical record. Radiation risks: NA POTENTIAL BENEFITS b. Potential benefits to society It is hoped that the results of this study may provide a benefit to others in the future including members of an affected patient's family since the gene mutation has a 50% chance of being passed on. Positive test results that lead to identification of other gene mutation carriers and characterization of their phenotype within a family, will broaden our understanding of the variability of expression in NS. New mutations identified in patients who only have cardiac disease can be used as models for the pathogenesis of valvular malformations and hypertrophic cardiomyopathy. By phenotypically characterizing the group without a detectable mutation, comparisons can be made between the two groups (mutation negative and mutation positive) to look for phenotypic differences. This may help in developing pre-test probabilities for future testing. The mutation negative group could be used for future research looking for additional NS candidate genes. Characterization of the mutations and their role in SHP-2 function will aid
in understanding the pathogenesis of Noonan syndrome and related disorders
phenotypes. MONITORING AND QUALITY ASSURANCE REFERENCES Allanson JE. Syndrome of the Month: Noonan Syndrome. J Med Genet. 1987; 24:9-13. Brady AF, Jamieson CR, van der Burgt I, Crosby A, van Reen M, Kremer H, Mariman E, Patton MA, Jeffrey S. Further delineation of the critical region for Noonan syndrome on the long arm of chromosome 12. Eur J Hum Genet. 1997; 5:336-337. Burch M, Sharland M, Shinebourne E, Smith G, Patton M, McKenna W. Cardiologic abnormalities in Noonan syndrome: phenotype diagnosis and echocardiographic assessment of 118 patients. JACC. 1993; 22(4):1189-92. Chen B, Bronson RT, Klaman LD, Hampton TG, Wang J, Green PJ, Magnuson T, Douglas PS, Morgan JP, Neel BG. Mice mutant for Egfr and Shp2 have defective cardiac semilunar valvulogenesis. Nat Genet. 2000; 24:296-299. Dechert U, Duncan AM, Bastien L, Duff C, Adam M, Jirik FR. Protein-tyrosine phosphatase SH-PTP2 (PTPN11) is localized to 12q24.1-24.3. Hum Genet. 1995; 96:609-615. George CD, Patton MA, el Sawi M, Sharland M, Adam EJ. Abdominal Ultrasound in Noonan syndrome: a study of 44 patients. Pediatr Radiol. 1993; 23:316-18. Ishizawa A, Oho S, Dodo H, Katori T, Homma SI. Cardiovascular abnormalities in Noonan syndrome: the clinical findings and treatments. Acta Paediatr Jpn. 1996; 38:84-90. Jamieson CR, van der Burgt I, Brady AF, van Reen M, Elsawi MM, Hol F, Jeffrey S, Patton MA, Mariman E. Mapping a gene for Noonan syndrome to the long arm of chromosome 12. Nat Genet. 1994; 8:357-60. Kosaki K, Suzuki T, Muroya K, Hasegawa T, Sato S, Matsuo N, Kosaki R, Nagai T, Hasegawa Y, Ogata T. PTPN11 (Protein-Tyrosine Phosphatase, Nonreceptor-Type 11) Mutations in Seven Japanese Patients with Noonan Syndrome. The Journal of Clinical Endocrinology and Metabolism. 2002; 87(8):3529-3533. Marino B, Diglio MC, Toscano A, Giannotti A, Dallapiccola B. Congenital heart diseases in children with Noonan syndrome: an expanded cardiac spectrum with high prevalence of atrioventricular canal. J Peds. 1999; 135:703-706. Mendez HM, Opitz JM. Noonan syndrome: a review. Am J Med Genet. 1985; 21:493-506. Noonan JA, Ehmke DA. Associated noncardiac malformations in children with congenital heart disease. J Pediatr. 1963; 468-469. Noonan JA. Noonan Syndrome: An update and review for the primary pediatrician. Clin Pediatr. 1994; 33(9):548-55. Noonan JA. Noonan syndrome revisited. J Peds. 1999; 135(6):667-668. Sarkozy A, Conti E, Digilio MC, Seripa D, Marino B, Matera MG, Esposito G, Fazio VM, Pizzuti A, Dallapiccola B. PTPN11 gene mutations in syndromic and nonsyndromic pulmonary valve stenosis. Am J Hum Genet. 2002 Sharland M, Patton MA, Talbot S, Chitolie a, Bevan DH. Coagulation-factor deficiencies and abnormal bleeding in Noonan's syndrome. The Lancet. 1992; 339:19-21. Tartaglia M, Mehler EL, Goldberg R, Zampino G, Brunner HG, Kremer H, van der Burgt I, Crosby AH, Ion A, Jeffrey S, Kalidas K, Patton MA, Kucherlapati RS, Gelb BD. Mutations in PTPN11, encoding the protein tyrosine phosphatase SHP-2, cause Noonan syndrome. Nat Genet. 2001; 465-468. Tartaglia M, Kalidas K, Shaw A, Song X, Musat DL, van der Burgt I, Brunner HG, Bertola DR, Crosby A, Ion A, Kucherlapati RS, Jeffrey S, Patton MA, Gelb BD. PTPN11 Mutations in Noonan Syndrome: Molecular spectrum, genotype-phenotype correlation, and phenotypic heterogeneity. Am J Hum Genet. 2002; 70:1555-1563. Van der Burgt I, Berends E, Lommen E, van Beersum S, Hamel B, Mariman E. Clinical and molecular studies in a large Dutch family with Noonan syndrome. Am J Med Genet. 1994; 53:187-191. Van der Burgt I, Brunner H. Genetic heterogeneity in Noonan syndrome:
evidence for an autosomal recessive form. Am J Med Genet 2000; 94:46-51. |
