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At a glance

This is a medical condition characterized by moderate intellectual deficit, brachycephaly, microstomia, very thin lips, ectomorphic (Marfanoid) habitus accompanied by extremely long, thin fingers and toes, as well as hypoplastic external genitalia.

Synonym

Arachnodactyly Mental Retardation Dysmorphism Syndrome.

Incidence

Approximately 10 cases have been described.

Genetic inheritance

Postulated to be autosomal recessive.

Pathophysiology

Unknown.

Diagnosis

Symptoms of the syndrome are apparent at birth. Diagnosis is based on physical signs of arachnodactyly and the characteristic facies associated with mental retardation.

Clinical aspects

Facies is long, narrow, and triangular in shape, with a large forehead and brachycephalic skull. Other facial characteristics are hypertelorism, microstomia with thin lips and flat philtrum, and an underdeveloped maxilla. Moderate-to-severe mental retardation with or without seizures is found. Patients present with long slender extremities, arachnodactyly comparable to Marfan Syndrome, and, in some cases, hyperextensible joints. Finger and toe anomalies, such as clinodactyly of the fourth and fifth fingers, triphalangeal thumbs, and hammer-shaped toes, can be present. Patients may be hypotonic with increased reflexes and underdeveloped musculature. Development of the external genitalia is delayed. Mitral regurgitation has been described in one case.

Precautions before anesthesia

Evaluate the airway carefully. The presence of microstomia can be suggestive of difficult airway management and proper preparation at the time of induction of anesthesia will be needed. If a cardiac lesion is suspected, obtain an ECG and an echocardiogram.

Anesthetic considerations

Direct laryngoscopy and tracheal intubation may be challenging. An inhalation induction while the child is kept spontaneously breathing probably is the best choice, considering the child is mentally delayed and can hardly cooperate with an awaken fiberoptic intubation. In the presence of a cardiac lesion, antibiotic prophylaxis for subacute bacterial endocarditis should be given.

Pharmacological implications

Secondary to the generalized hypotonia and poorly developed musculature, neuromuscular blocking agents may not be needed at all or only in a reduced dosage. If the patient is on anticonvulsant medication, liver enzymes may be induced and hasten the metabolism of drugs with predominantly hepatic metabolism.

Other conditions to be considered

  • Lujan Fryns Syndrome: Inherited syndrome with marfanoid features and X-linked mental retardation.

  • Marfan Syndrome: Autosomal dominant inherited disorder with generalized connective tissue abnormalities. Aortic regurgitation and dissection are responsible for premature death in the third to fifth decade.

  • Van Benthem-Driessen-Hanveld Syndrome (Cryptorchidism-Arachnodactyly-Intellectual Disability Syndrome): Characterized by psychomotor delay, severe intellectual deficit, severe muscle hypoplasia, absence of subcutaneous fat, and generalized contractures. Other important clinical features include craniofacial dysmorphic anomalies such as dolichocephaly, esotropia, unequal size ears, and a high restrictive palate. Kyphoscoliosis, ...

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