Tricho-Rhino-Phalangeal Dysplasia Type I

At a glance

Syndrome characterized by facial anomalies (bulbous nose, cone-shaped epiphyses), high-arched palate, and horizontal groove on the chin. Also includes hypoplastic nails and short metatarsal and metacarpals joints, sparse hair.

Synonym

TRPS I.

History

First reported by German dermatologist Klingmüller in 1956.

Incidence

Rare, although more than 30 cases have been identified. Males affected more often than females.

Genetic inheritance

Autosomal dominant contiguous gene syndrome, probably the result of chromosome 8 deletion. An autosomal recessive trait has also been suggested.

Pathophysiology

It is caused by haploinsufficiency of a specific zinc finger protein that is putative transcription factor (TRPS I).

Diagnosis

Clinical supported by genetic analysis. Long bone radiographs reveal cone-shaped epiphyses.

Clinical aspects

Tendency for bone fracture and variable growth; hyperextensible joints. Scoliosis is also present. Characteristic appearance with bulbous broad nose, bushy eyebrows, sparse scalp hair, dental abnormalities. It may present with recurrent pulmonary infections, often associated with pectus carinatum. Neonatal hypotonia has been reported. Micrognathia, prune-belly sequence. Ureteral reflux, persistent cloaca, congenital nephrotic syndrome. Rarely, but suggested, aplasia of epiglottis.

Precautions before anesthesia

Assessment of severity of previous bony problems, which facilitates preoperative positioning. Exclusion of respiratory infection clinically and, if indicated, by chest radiography. Assess airway for micrognathia and epiglottic aplasia.

Anesthetic considerations

Careful positioning and padding because of the tendency to fracture. Direct laryngoscopy and tracheal intubation might be difficult because of the micrognathia and the potential for epiglottic aplasia or laryngeal structure deformity. Spontaneous respiration must be maintained until the trachea has been intubated and lung ventilation is confirmed. The immediate availability of a laryngeal mask airway in case of failure to intubate the trachea is recommended. Fiberoptic equipment may be needed and should be available. The presence of abnormal dentition should also be kept in mind to avoid trauma during laryngoscopy.

Pharmacological implications

Prophylactic antibiotics may be indicated for respiratory or urogenital indications.

Other conditions to be considered

• ☞Tricho-Rhino-Phalangeal Dysplasia Type III: Genetic multisystem disorder (ectodermal dysplasia) characterized by mild postnatal growth deficiency with mental retardation, thin hair, unusual facial features, brachydactyly, microencephaly, multiple exostoses, musculoskeletal dysplasia, and redundant skin.

• ☞Langer-Giedion Syndrome (Tricho-Rhino-Phalangeal Dysplasia Type II): Characterized by mental retardation, multiple exostoses, peculiar facies, and loose redundant skin. It is known as one of the few congenital contiguous gene syndromes and is present from birth. The facial features include a bulbous nose with thickened septum and alae, wide prominent philtrum, thin upper lips, and ...