Noonan syndrome is a genetic disorder that may present with mildly unusual facial features, short height, congenital heart disease, bleeding problems, and skeletal malformations. Facial features include widely spaced eyes, light-colored eyes, low-set ears, a short neck, and a small lower jaw.
behavioural problems – some children with Noonan syndrome may be fussy eaters, behave immaturely compared to children of a similar age, have problems with attention and have difficulty recognising or describing their or other people's emotions.
Symptoms of Noonan syndrome vary from mild to life-threatening, depending on the affected part of your child's body. Most symptoms start when the fetus is developing in the uterus or appear in children before age 11. Facial features of children with Noonan syndrome often become less noticeable as children get older.
Noonan syndrome is a condition that some babies are born with. It causes changes in the face and chest, usually includes heart problems, and slightly raises a child's risk of blood cancer (leukemia). Noonan syndrome is a pretty common condition, affecting 1 in 1,000–2,500 babies.
Up to 35 per cent of people with Noonan syndrome will have a mild intellectual disability, but most people will be unaffected. People who experience intellectual disability with Noonan syndrome may also experience developmental delays with their speech, language and coordination.
Facial features
Noonan syndrome may include these features: Eyes are wide-set, slant down and have droopy lids. Eyes may be pale blue or green. Ears are set low and look like they're tipped backward.
In many cases, the problems associated with the condition can be successfully treated at a young age or become less prominent over time. Almost all children with Noonan syndrome reach adulthood and most are able to lead normal, independent lives.
Most children diagnosed with Noonan syndrome have normal intelligence, but a few have special educational needs, and some have intellectual disability. Some affected individuals have vision or hearing problems. Affected infants may have feeding problems, which typically get better by age 1 or 2 years.
ASD & Noonan Syndrome
There is a 15-30% prevalence of autism in NS. This is not surprising given genome analysis has shown the RAS/MAPK pathway is involved in autism and mutations in this pathway are responsible for Noonan Syndrome. This is significantly higher incidence of ASD than in the non-NS population (1.5%).
Life expectancy with Noonan syndrome is generally normal, but there may be health problems that need to be addressed with medical or surgical attention. Bleeding can result in blood loss, which can cause symptoms of fatigue.
Noonan syndrome appears to affect more males than females and is thought to affect approximately one in 1,000 to one in 2,500 people.
Mean final height was 147.2 cm (range 142.9–151.4) in girls and 159.9 cm (range 155.6–166.2) in boys.
Although cognitive impairments in adults with Noonan syndrome seem to be limited to a low‐average intelligence and slower processing speed, studies in children with Noonan syndrome have demonstrated more extensive cognitive problems.
NS is known to adversely affect memory, attention, visual processing, communication and executive functions. Children with NS (and all RASopathies for that matter) show common learning difficulties such as impaired reading/vocabulary, visuospatial function, planning and organisational skills.
Twenty percent of those with Noonan Syndrome have mutations in the SOS1. Mutations in the RAF1 gene account for between 10 and 15 percent of Noonan syndrome cases. About 5 percent of people with Noonan syndrome have mutations in the KRAS gene and usually have a more severe or atypical form of the disorder.
Musculoskeletal pain was found in 18 patients (25%) and joint stiffness in 10 (14%) located in the wrists, elbows, ankles, knees and hips, which was usually bilateral.
From the Department of Psychiatry and Behavioral Sciences and the Department of Pediatrics, The Johns Hopkins University and Hospital, Baltimore. The IQ of eight male patients with Noonan's syndrome, aged 13 to 26 years, ranged from 64 to 127, with a median of 102.
How Noonan syndrome is inherited. In around 30-75% of cases, Noonan syndrome is inherited in what's known as an autosomal dominant pattern. This means that only one parent has to carry a copy of one of the faulty genes to pass it on, and each child they have will have a 50% chance of being born with Noonan syndrome.
About Noonan syndrome
Many rare diseases have limited information. Currently GARD aims to provide the following information for this disease: Population Estimate:Fewer than 200,000 people in the U.S. have thisdisease. Symptoms:May start to appear at a variety of ages.
But this can be difficult because some features of the condition are not easily seen and are hard to find. Sometimes Noonan syndrome is not found until adulthood, after a person has a child who is more clearly affected by the condition. Genetic testing can confirm a diagnosis.
Before your baby is born, your doctor might consider that he has Noonan syndrome if a pregnancy ultrasound shows: Extra amniotic fluid around your baby in the amniotic sac. A cluster of cysts in your baby's neck. Problems with their heart structure or other structural problems.
We report our findings in 73 adults over 21 years of age with NS. Thirty percent of this group had an adult height in the normal range between 10th percentile and 90th percentile. Over half of the females and nearly 40% of males had an adult height below the 3rd percentile.
In children with Noonan syndrome, puberty can be delayed by about 2 years. The pubertal growth spurt is often reduced or absent. Bone development may also be delayed by 2 years.
In children with Noonan syndrome, weak muscles in the mouth can sometimes cause speech and feeding problems. They may be referred to a speech therapist for help and support. The speech therapist will help your child develop the muscles in their mouth and try to teach them how to use their muscles more effectively.
You may be referred to a genetics specialist for genetic testing. In most cases, Noonan syndrome can be confirmed by a blood test for the various genetic mutations.