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.
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
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.
Raymond GV: Peroxisomal disorders. Curr Opin Pediatr 11(6):572, 1999.
White AL, Modaff P, Holland-Morris F, et al: Natural history of rhizomelic
chondrodysplasia punctata. Am J Med Genet 118A(4):332, 2003.