Rhizomelic Chondrodysplasia Punctata Type I

Peroxisomal disorder belonging to the chondrodysplasia punctata group. Punctate calcifications and rhizomelia, congenital cataract, and progressive mental retardation are the main features. Poor prognosis.

RCDPI; Chondrodystrophia Calcificans Punctata.

Rare; 1:100,000 live births.

Autosomal recessive.

Caused by defective peroxisome metabolism as a result of a mutation in the PEX7 gene, which encodes the peroxisomal type 2 targeting signal (PTS2) receptor gene located in 6q22-q24.

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.

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.

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).

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. 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.

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 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.