Rhizomelic Chondrodysplasia Punctata (RCDP)

At a glance

Rhizomelic chondrodysplasia punctata is a class of peroxisomal disorders characterized by defective plasmalogen biosynthesis. Punctate calcifications, rhizomelia, congenital cataract, and progressive mental retardation are the main features. Poor prognosis.

Synonyms

RCDP; Chondrodystrophia Calcificans Punctata.

Incidence

Rare; less than 1:100,000 live births.

Genetic inheritance

Autosomal recessive.

Pathophysiology

Multiple RCDP are recognized and caused by defective peroxisome metabolism as a result of a mutation. RCDP type 1 with PEX7, RCDP type 2 with GNPAT, RCDP type 3 with AGPS, RCDP type 4 with FAR1, and RCDP type 5 with PEX5.

Diagnosis

The combination of punctate calcifications, rhizomelia, and biochemical abnormalities (deficient red cell plasmalogens, increased concentration of phytanic acid) is pathognomic. Antenatal diagnosis by identifying peroxisome enzymes in fetal blood is possible.

Clinical aspects

Features involve skeleton (scoliosis, punctate epiphysis, metaphyseal anomaly, rhizomelic micromelia, short stature, spina bifida occulta, restricted joint mobility), head (microcephaly; congenital bilateral and symmetric cataract; flat face; epicanthic folds; micrognathia; cleft palate; high forehead; small, upturned nose; long, flat philtrum), central nervous system (CNS) (sensorineural deafness, mental retardation, seizures developed between 18 months and 5 years of age), and skin (ichthyosis, alopecia). Dislocated hips and shoulder and cardiac malformations (atrial defect, mitral valve prolapse) have been described. Respiratory infections are frequent as a consequence of aspiration; 60% of patients die during the first year of life, and all die before reaching the teen years.

Precautions before anesthesia

Evaluate pulmonary function (clinical, chest radiographs, pulmonary function test if necessary, arterial blood gas analysis); neurological function (clinical, history, EEG, CT/MRI); cardiac function (clinical, ECG, echography); and tracheal intubation (clinical, radiographs).

Anesthetic considerations

Perioperative physiotherapy is needed to avoid pulmonary superinfection. Airway management can be difficult because of cleft palate and micrognathia. Careful intraoperative positioning is needed because of skeletal defect. Particular attention needs to be paid to the possibility of cervical spine stenosis and cord compression. Regional anesthesia is not contraindicated, but can be difficult to perform. Rapid sequence induction should be considered because of the high risk of pulmonary aspiration.

Pharmacological implications

Consider interaction between antiepileptic treatment and anesthetic drugs. Prophylactic antibiotics in case of cardiopathy as indicated. Muscle relaxants should be avoided until airway is secured.

Other conditions to be considered

Other chondrodysplasia punctata, as well as the following:

• Rhizomelic Chondrodysplasia Type II (RCDPII): RCDP caused by dihydroxyacetone phosphate acyltransferase deficiency. Clinical features are identical to the RCDPI.

• Rhizomelic Chondrodysplasia Type III (RCDPIII): Autosomal recessive peroxisomal disorder caused by alkyldihydroxyacetonephosphate synthase (alkyl-DHAP synthase) deficiency ...