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ICH and S-ABC are equal first authors.
Introduction
Rhizomelic chondrodysplasia punctata (RCDP) is an autosomal recessive peroxisomal disorder.1 The classic RCDP patient presents with symmetrical rhizomelia, contractures, congenital cataracts, facial dysmorphia, severe psychomotor defects and growth retardation (see figure 1). X-Ray features include rhizomelia, punctate calcifications in meta- and epiphyses and coronal clefts in the vertebrae. Magnetic resonance images of the brain demonstrate developmental and degenerative abnormalities.2 There are three genetic subtypes, all resulting in a defect in plasmalogen biosynthesis. Plasmalogens are vinyl-ether-phospholipids which are major constituents of cellular membranes. RCDP type 1 is caused by mutations in the PEX7 gene, which codes for the peroxisomal targeting signal 2-receptor protein peroxin 7,3 leading to a deficient plasmalogen biosynthesis. RCDP types 2 and 3 are caused by mutations in genes coding for the two peroxisomal enzymes involved in plasmalogen biosynthesis, dihydroxyacetonephosphate acyltransferase4 and alkyl-dihydroxyacetonephosphate synthase,5 respectively. In RCDP type 1 patients, but not in type 2 and 3 patients, plasma phytanic acid levels are usually elevated due to a block in phytanic acid α-oxidation as a result of the PEX7 deficiency.1 Clinically the different types of RCDP cannot be distinguished.6 Biochemically, all types have low erythrocyte plasmalogen levels and normal very long chain fatty acid levels.
Although congenital heart disease (CHD) has been described in patients with RCDP,7–15 it is not generally considered a clinical feature of RCDP.15 We noticed several cases with CHD in our cohort and this prompted us to perform the current study.
The aim of this study was to describe the CHD found and to determine the prevalence of CHD in our cohort and to compare our findings with data already described in the literature. Furthermore, we aimed to describe genetic, biochemical and cardiac correlations.
Methods
Our institution is a national referral centre for RCDP. In the years between 2000 and 2012 we have cared for 23 patients with genetically proven RCDP. Their data were retrospectively evaluated by reviewing the patient files. Demographic data, genetic subtype, plasmalogen levels in erythrocytes at time of RCDP diagnosis, phytanic acid levels in plasma and physical examination were recorded.
Identification of the genotype, measurement of the plasmalogens in erythrocytes and phytanic acid in plasma were performed using...