Noonan syndrome 3


A genetic condition characterized by short stature, distinctive facial characteristics, learning difficulties, congenital heart conditions and various other anomalies


The list of medical symptoms mentioned in various sources for Noonan syndrome 3 includes those listed below. Note that Noonan syndrome 3 symptoms usually refers to various medical symptoms known to a patient, but the phrase Noonan syndrome 3 signs may often refer to those signs that are only noticable by a doctor: * Mental retardation * Stunted growth * Absence of male genitalia * Absent sexual development * Primary amenorrhea * Congenital anomalies * Short stature * Undescended testes * Pulmonary valvular stenosis * Arterial stenosis * Congenital heart malformations * Drooping upper eyelid * Widely spaced eyes * Antimongoloid slanting space between eyelids * Ear abnormalities * Small jaw * Dental anomalies * Uvula anomalies * Mouth roof anomalies * Pigeon breast * Vertebral anomalies * Digital anomalies * Dysonchia * Thick hair * Webbed neck * Multiple café au lait spots


Both sporadic and autosomal dominant cases have been identified. At least 4 disease-causing genes have been found.1, 2, 3, 4, 5 * PTPN11 mutations account for approximately 50% of clinically recognized cases. * SOS1 mutations account for approximately 10% of cases. * RAF1 mutations account for 3-17% of cases. * KRAS mutations account for approximately 1% of cases.


The prenatal history is typically unremarkable; however, some cases are complicated by polyhydramnios, fetal edema, or cystic hygroma. * A careful family history should be obtained, paying particular attention to the presence of congenital heart disease, mental retardation, short stature, or unusual facies among the parents or siblings of an affected child. * A child with mild expression of the facial phenotype might only present with developmental delay and history of congenital heart disease. A history of abnormal bleeding is present in as many as 50% of patients. Physical * Growth parameters o Size at birth is usually within the reference range. o Short stature is present in as many as 80% of patients. Average adult height for is 5 ft 5 inches in males and 5 ft in females. * Facial features o Triangular-shaped face o Hypertelorism o Down-slanting eyes o Ptosis o Strabismus (48%) o Amblyopia (33%) o Refractive errors (61%) o Low-set ears with thickened helices o High nasal bridge o Short webbed neck * Chest/back features o Pectus carinatum or excavatum o Scoliosis * Cardiac features: The characteristic lesion is dysplastic/stenotic pulmonic valve, but virtually all types of congenital heart defects have been described in patients with Noonan syndrome. Hypertrophic cardiomyopathy (obstructive and nonobstructive types) is present in as many as 30% of patients. * Abdominal features: Hepatosplenomegaly unrelated to cardiac status is present in approximately 25% of patients. * Genitourinary features o Renal anomalies are present in 10% of patients but are not clinically significant. o More than half of male patients have undescended testes. * Skeletal features o Joint laxity is present in more than half of patients. o Talipes equinovarus, radioulnar synostosis, cervical spine fusion, and joint contractures are less common findings. * Skin findings o Lymphedema o Prominent pads of fingers and toes (67%) o Follicular keratosis of face and extensor surfaces (14%) o Multiple lentigines (3%) * Neurologic findings o Hypotonia o Seizure disorder (13%) o Unexplained peripheral neuropathy (infrequent)