Tricho-Rhino-Phalangeal Dysplasia Type II

At a glance

Genetic multisystem disorder (ectodermal dysplasia) characterized by mild postnatal growth deficiency with mental retardation, thin hair, unusual facial features (bulbous nose), redundant skin, brachydactyly, and multiple exostoses.

Synonyms

Langer-Giedion Syndrome; Acrodysplasia V; Acrodys­plasia Dysostoses Syndrome; Alè-Calò Syndrome; Giedion-Langer Syndrome; Klingmüller Syndrome; Multiple Exostoses-Mental Retardation (MEMR) Syndrome; Trichorhino Auriculophalangeal Multiple Exostoses (TRAMPE) Dysplasia; Trichorhinophalangeal Syndrome with Exostoses.

History

Postnatal growth retardation associated with mild-to-moderate mental retardation and multiple cartilaginous exostoses described by A. Giedion, a Swiss radiologist and L. Langer, an American radiologist.

Incidence

Rare. Both sexes affected equally.

Genetic inheritance

Usually sporadic, but some cases autosomal dominant. Chromosome deletion extending from 8q24.11 to 8q24.13. One of the contiguous gene syndromes (group of disorders associated with chromosomal microdeletions or microduplications).

Pathophysiology

Contiguous gene syndrome involving loss of functional copies of TRPS I and EXT 1 genes. Deletion of 8q24.13 results in bone exostoses and mental retardation especially when large pieces of 8q are deleted. Intellectual disability and loose skin are the result of deletion of genes outside the TRPS I-EXT 1 interval.

Diagnosis

Clinical features supported by genetic analysis. Long bone radiographs reveal cone-shaped epiphyses and the presence of exostoses.

Clinical aspects

Exostoses of bone with tendency for bone fracture and variable growth, hyperextensible joints. Scoliosis may be present. Redundant skin and, therefore, frequently misdiagnosed as having the Ehlers-Danlos Syndrome. Microcephaly, characteristic appearance with bulbous broad nose, bushy eyebrows, sparse scalp hair, dental abnormalities. Mental retardation, neonatal hypotonia, delayed speech development, hearing loss. Recurrent respiratory infections until they are 4 to 5 years old. Prune-belly sequence. Ureteral reflux, persistent cloaca, congenital nephrotic syndrome. Aplasia of epiglottis may be present.

Precautions before anesthesia

Assessment of severity of syndrome, previous bony problems, and degree of mental retardation. Exclusion of respiratory infection clinically and, if indicated, by chest radiography. Assessment of genitourinary abnormalities and referral to exclude abnormalities may be indicated. Assessment of rare complications such as prune belly and epiglottic aplasia must be conducted.

Anesthetic considerations

Premedication may be indicated if patient is uncooperative because of mental retardation. Intravenous access may be difficult because of the redundant skin. Careful positioning and padding is highly recommended because of the tendency to spontaneous bone fracture.

Pharmacological implications

Prophylactic antibiotics may be indicated for ...