Table 1.

Clinical Features of Noonan Syndrome

Cardiovascular4,5 Hypertrophic cardiomyopathy Pulmonary stenosis, often with  a dysplastic valve Dental/oral1,2 Articulation difficulty High arched palate Malocclusion Micrognathia Dysmorphic facial features6,7 See Figures 1 through 4 Ears8 Hearing loss Eyes2,9 Anterior segment problems  (prominent corneal nerves, cataract,  anterior stromal dystrophy) Nystagmus Ptosis, hypertelorism, and epicanthal  folds Refractive error Strabismus Gastrointestinal3,4 Feeding difficulties (poor sucking  function, prolonged feeding time,  recurrent vomiting and reflux)

Genitourinary2,8 Cryptorchidism Female fertility is normal Males can have fertility issues (e.g., defective  spermatogenesis caused by cryptorchidism,  gonadal dysfunction due to impaired  Sertoli cell function) Malformations (renal pelvis dilation, solitary  kidney, duplex collecting system) Puberty can be delayed in both sexes Growth2,4,8 Birth weight and length are normal Failure to thrive and short stature (50% to  70% of patients with Noonan syndrome) Mean final adult height is 63 to 66 inches  (160 to 168 cm) in males and 59 to 61  inches (150 to 155 cm) in females Hematologic 1,3,4,10,11 Increased bleeding tendency (due to factor  deficiency, quantitative or qualitative  platelet defect) Leukemia Myeloproliferative disorder Lymphatic8 Lymphedema

Neurologic1,8 Behavioral conditions (stubbornness, irritability,  body image problems, poor self-esteem) Central nervous system malformation Early motor milestones delay (hypotonia and  joint laxity) Learning difficulties Mild intellectual disability (33% of patients  with Noonan syndrome) Most individuals have normal intelligence Speech disorders Skeletal2,4 Cubitus valgus Spinal abnormality (scoliosis, talipes  equinovarus) Sternal deformities (pectus carinatum  superiorly, pectus excavatum inferiorly) Skin conditions2,4 Dystrophic nails Extra prominence on pads of fingers and toes Follicular keratosis Hyperelastic skin Moles Multiple lentigines Nevi Thick curly hair or thin sparse hair

Information from references 1 through 11.