Novel CTSK mutation resulting in an entire exon 2 skipping in a Thai girl with pycnodysostosis |
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Authors: | Pattarapa Utokpat Wipa Panmontha Siraprapa Tongkobpetch Kanya Suphapeetiporn Vorasuk Shotelersuk |
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Affiliation: | 1. Center of Excellence for Medical Genetics, Department of Pediatrics, Chulalongkorn University, , Bangkok, Thailand;2. Excellence Center for Medical Genetics, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, , Bangkok, Thailand;3. Department of Medical Sciences, Faculty of Medicine, Chulalongkorn University, , Bangkok, Thailand |
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Abstract: | Pycnodysostosis is a rare autosomal recessive skeletal dysplasia characterized by osteosclerosis, short stature, acro‐osteolysis of the distal phalanges, bone fragility and skull deformities. Mutations in the cathepsin K (CTSK) gene, which encodes a lysosomal cysteine protease highly expressed in osteoclasts, have been found to be responsible for the disease. We identified a Thai girl with pycnodysostosis. Her parents were first cousins. Polymerase chain reaction sequencing of the entire coding regions of CTSK of the proband's complementary DNA revealed that the whole exon 2 was skipped. We subsequently amplified exon 2 using genomic DNA, which showed that the patient was homozygous for a c.120G>A mutation. The mutation was located at the last nucleotide of exon 2. Its presence was confirmed by restriction enzyme analysis using BanI. The skipping of exon 2 eliminates the normal start codon. The mutation has never been previously reported, thus the current report expands the CTSK mutational spectrum. |
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Keywords: | cathepsin K CTSK exon skipping mutation pycnodysostosis |
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