Skip to Main Content

++

Although most neonates and infants with this disorder appear to develop normally in the first few months of life, the presence of poor muscle tone most often already is present at birth. By age 6 months, hypotonia, inability to hold up the head, and severe muscle atrophy are detectable. Severe mental retardation is associated with multiple congenital anomalies.

++

Allan-Herndon-Dudley Syndrome; AHDS; X-Linked Mental Retardation with Hypotonia.

++

X-linked recessive. Gene located in Xq21.

++

Based on clinical features and family history.

++

Only males are affected. Except for hypotonia, these boys appear normal at birth. When the child is approximately 6 months old, the parents often notice that the child is unable to hold up the head. Motor development is severely impaired so that the ability to walk is achieved either very late or not at all. Generalized muscular atrophy, which is associated with myopathic findings on histologic examination, becomes obvious in early infancy. Later in infancy, spastic paraplegia with joint contractures, hyperreflexia with clonus, ataxia, athetosis, and dysarthria become increasingly more obvious. Scoliosis may occur. Mental retardation usually is severe. Craniofacial anomalies may include elongation and bitemporal narrowing of the head with enlarged and dysplastic ears. Pectus excavatum has been described in many of these boys.

++

Assess the degree of scoliosis, pectus excavatum, and joint contractures. If scoliosis or pectus excavatum is severe, assess pulmonary function and obtain a chest radiograph, arterial blood gas analysis, and pulmonary function tests if possible. Echocardiography may be indicated if there are any concerns about heart function (cor pulmonale).

++

The presence of severe mental retardation suggests a lack of cooperation, and sedation in the older child prior to induction of anesthesia may be required. Careful positioning and padding are required because of contractures. Depending on the degree of scoliosis and pectus excavatum, postoperative mechanical ventilation may be required. As in any patient with signs of muscular hypotonia and/or myopathy, depolarizing muscle relaxants should be used only with caution. Whether these patients have a predisposition to malignant hyperthermia is unknown, but it may be wise to provide a trigger-free anesthesia.

++

None reported; however, an exaggerated hyperkalemic response to succinylcholine should be expected. No data on the predisposition to malignant hyperthermia are available, so use of succinylcholine probably is best reserved for special situations.

++

Fragile X Syndrome: The most common form of X-linked mental retardation (XLMR). Affects males more often and more severely than females. Only subtle dysmorphic features. Behavioral issues may be more pronounced.

++

Juberg-Marsidi Syndrome: X-linked recessive inherited syndrome characterized by severe mental retardation, deafness, failure to thrive, microgenitalism, and early death.

++

Happy Puppet Syndrome: Rare disorder characterized by developmental delay, ataxia, dysmorphic facial features, and seizures associated with a happy, sociable disposition.

++

MASA Syndrome: Extremely rare inherited disorder that is one of several disorders known ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessAnesthesiology Full Site: One-Year Subscription

Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessAnesthesiology

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.