Late diagnosis of maternal PKU in a family segregating an arylsulfatase [corrected] E mutation causing symmetrical chondrodysplasia punctata

A rare lethal case of chondrodysplasia punctata with extensive airway involvement

Stippled cartilaginous calcification, an important radiologic sign, is described as ''chondrodysplasia punctata'' when seen in association with limb shortening and maxillofacial hypoplasia. We report chondrodysplasia punctata in a male neonate who presented with limb shortening, midfacial hypoplasia, and laryngeal stenosis leading to death within a few minutes of birth. A post-mortem radiograph revealed generalized punctate calcification of cartilaginous structures, including airways, rib ends, spine, long bone epiphyses, tarsus and pinna, and brachytelephalangy.

X-linked brachytelephalangic chondrodysplasia punctata: a simple trait that is not so simple

Brachytelephalangic chondrodysplasia punctata (CDPX1) is an X-linked recessive disorder caused by mutations in the arylsulfatase E (ARSE) gene, characterized by the presence of stippled epiphyses on radiograms in infancy and early childhood. Other features include hypoplasia of the midface and of the nasal bone, short stature, brachytelephalangy, and ectopic calcifications. Patients display marked clinical variability and there is no clear genotype-phenotype correlation. We report on a 14-month-old boy who presented with respiratory stridor due to tracheal calcifications. He had mild midface hypoplasia and brachytelephalangy, but lacked other features of CDPX1, such as short stature and epiphyseal stippling. Analysis of ARSE detected a deletion involving exons 7-10. His maternal grandfather harbored the same defect but lacked any clinical manifestation. These findings underscore two important points. First, the absence of stippled epiphyses on radiograms should not be considered an exclusion criteria for ARSE mutation screening in patients with other features of the disease, especially after the neonatal period. Second, counseling to parents of affected children should be cautious because although the theoretical risk of inheriting the ARSE mutation is 50% for every male child of a carrier mother, it is not possible to determine whether he will develop features of CDPX1 and the eventual severity of symptoms. The actual risk of developing the disease is probably lower than 50%. Conversely, normal prenatal sonography does not rule out potentially severe complications such as tracheal stenosis.

Chondrodysplasia punctata: a clinical diagnostic and radiological review

Chondrodysplasia punctata (CDP) is associated with a number of disorders, including inborn errors of metabolism, involving peroxisomal and cholesterol pathways, embryopathy and chromosomal abnormalities. Several classification systems of the different types of CDP have been suggested earlier. More recently, the biochemical and molecular basis of a number of CDP syndromes has recently been elucidated and a new aetiological classification has emerged. Here we provide an updated version with an overview of the different types of CDP, a discussion of the aetiology and a description of the clinical and radiographic findings. An investigative guideline to help determine the exact diagnosis in new cases is also presented.

Identification of tyrosine sulfation in extracellular leucine-rich repeat proteins using mass spectrometry

Multiple and variable tyrosine sulfation in extracellular class II leucine-rich repeat proteins/proteoglycans were characterized by mass spectrometry. The sulfogroup on tyrosine is labile and is released from peptides under normal mass spectrometric conditions. Thus, special approaches must be considered in order to identify this modification. By using a combination of mass spectrometry studies operating in negative and positive ion mode, tyrosine sulfation could be identified. In positive mode, the peptides normally appeared non-sulfated, whereas in negative mode a mixture of sulfated and non-sulfated species was observed. A combination of peptides released by different proteinases was used to obtain details on the locations of sulfate groups. Multiple tyrosine sulfates were observed in the N-terminal region of fibromodulin (up to 9 sites), osteoadherin (up to 6 sites), and lumican (2 sites). Osteoadherin contains two additional sulfated tyrosine residues close to its C terminus. We also identified an error in the published sequence of bovine fibromodulin, resulting in the replacement of Thr37 by Tyr37-Gly38, thus increasing its homology with its human counterpart.

Low mutant load of mitochondrial DNA G13513A mutation can cause Leigh's disease

Respiratory chain complex I deficiency is a common cause of Leigh's disease (LD) and can be caused by mutations in genes encoded by either nuclear or mitochondrial DNA (mtDNA). Most pathogenic mtDNA mutations act recessively and only cause disease when present at high mutant loads (typically >90%) in tissues such as muscle and brain. Two mitochondrial DNA mutations in complex I subunit genes, G14459A in ND6, and T12706C in ND5, have been associated with complex I deficiency and LD. We report another ND5 mutation, G13513A, in three unrelated patients with complex I deficiency and LD. The G13513A mutation was present at mutant loads of approximately 50% or less in all tissues tested, including multiple brain regions. The threshold mutant load for causing a complex I defect in cultured cells was approximately 30%. Blue Native polyacrylamide gel electrophoresis showed that fibroblasts with 45% G13513A mutant load had approximately 50% of the normal amount of fully assembled complex I. Fibroblasts with greater than 97% of the ND6 G14459A mutation had only 20% fully assembled complex I, suggesting that both mutations disrupt complex I assembly or turnover. We conclude that the G13513A mutation causes a complex I defect when present at unusually low mutant load and may act dominantly.

Longterm follow-up in chondrodysplasia punctata, tibia-metacarpal type, demonstrating natural history

We report the longterm clinical and radiological progression in three unrelated patients with the tibia-metacarpal form of chondrodysplasia punctata (CDP-TM). The patients were followed for 37, 25, and 32 years, respectively. At follow-up intellectual function was normal, and physical function was well preserved. There was also marked resolution of several significant early radiographic features. The patients attained adult heights of 152, 138, and 148 cm. Two patients had chronic serous otitis media requiring tympanostomy tubes during childhood. One patient suffered persisting back pain related to spinal stenosis and required lumbar laminectomy at the age of 26 years. One patient had hip dysplasia requiring orthopedic surgical intervention. All patients had recurrent patella dislocation. Sterol and very long chain fatty acid profiles, FISH analysis for SHOX gene deletions, blood lymphocyte karyotype, and phytanic acid levels were normal in those tested, and no mutations in arylsulfatase D and E genes were detected. These data suggest that the longterm clinical and functional prognosis in this condition appears to be better than that expected based on initial clinical and radiological findings.