Genetic changes in the RNA components of RNase MRP and RNase P in Schmid metaphyseal chondrodysplasia.
BACKGROUND
The Schmid type of metaphyseal chondrodysplasia (MCDS) is generally due to mutations in COL10A1 encoding for type X collagen of cartilage.


METHODS
We performed a study on the genes coding for the RNA components of RNase MRP (MRPR) and RNase P (H1RNA) among 20 patients with diagnosis of MCDS and no mutations in COL10A1.


RESULTS
Two patients were found to be homozygous for a base substitution G for A at nucleotide 70 of RMRP, which is the major mutation causing cartilage-hair hypoplasia. No pathogenic mutations were detected in H1RNA.


CONCLUSIONS
Cartilage-hair hypoplasia diagnosis should be considered in patients with metaphyseal chondrodysplasia even in the absence of any extra-skeletal manifestations if no mutation in COL10A1 can be found and the family history is compatible with autosomal recessive inheritance. Correct diagnosis is important for genetic counselling and for proper follow up of the patients.
Folkhälsan Institute of Genetics and Department of Medical Genetics, Biomedicum Helsinki, FI-00014 University of Helsinki, Finland.
M
M
Ridanpää
L M
LM
Ward
S
S
Rockas
M
M
Särkioja
H
H
Mäkelä
M
M
Susic
F H
FH
Glorieux
W G
WG
Cole
O
O
Mäkitie
D002675:Child, Preschool; D004722:Endoribonucleases / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D010009:Osteochondrodysplasias / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics*; D012313:RNA / Q000235:genetics; D016337:RNA, Catalytic / Q000235:genetics*; D011859:Radiography; D043262:Ribonuclease P
D016337:RNA, Catalytic; D012313:RNA; D004722:Endoribonucleases; C058330:mitochondrial RNA-processing endoribonuclease; C468368:RPP14 protein, human; D043262:Ribonuclease P