Identification of molecular defects in a subject with type I CD36 deficiency

Abstract

We performed a molecular analysis of a subject whose platelets and monocytes did not express any cell surface CD36 (designated as a type I CD36 deficiency). Amplification of the 5′ half of platelet and monocyte CD36cDNA (corresponding to nucleotide [nt] 191–1009 of the published CD36 cDNA sequence [Oquendo et al, Cell, 58:95, 1989]) showed that two different-sized CD36 cDNAs existed. One cDNA was of predicted normal size, whereas the other was about 150 bp smaller than that predicted for normal CD36 cDNA. Amplification of the 3′ region of CD36 cDNA (nt 962–1714) in this subject showed only normal-sized CD36 cDNA. Cloning and nt sequence analysis of the cDNAs showed that the smaller sized CD36 cDNA had 161-bp deletion (from nt 331 to 491), and a dinucleotide deletion starting at nt position 539. The same dinucleotide deletion was also detected in the normal sized CD36 cDNA. Both deletions caused a frameshift leading to the appearance of a translation stop codon. RNA blot analysis and quantitative assay using the reverse transcription- polymerase chain reaction (RT-PCR) showed that the CD36 transcripts in both platelets and monocytes were greatly reduced. Comparison of the determined cDNA sequences with the genomic DNA sequence for the human CD36 gene showed that the dinucleotide deletion was located in exon 5, and that the 161-bp deletion corresponded to a loss of exon 4. PCR- based analysis using genomic DNA showed that this subject was homozygous for the dinucleotide deletion in exon 5. Except for the dinucleotide deletion, we could not find any abnormalities around exon 3, 4, and 5 including the splice junctions. These results suggested that the deletions in CD36 mRNA were likely to be responsible for instability of the transcripts, and the dinucleotide deletion in exon 5 might affect the splicing of exon 4.

Incidence and molecular basis of CD36 deficiency in Shanghai population

“…In individuals with Type I CD36 deficiency, a two-nucleotide deletion (329-330delAC) was found in one donor (Donor 1), which was located in Exon 5 and caused frameshift at Amino Acid Residue 110 as previously reported. 16 Moreover, a , which led to missense amino acid substitution Pro124Leu. Among 11 Type II CD36-deficient individuals with mutations, a deletion of 12 nucleotides (1228-1239delATTGTGCCTATT in heterozygous form) was found to be located in Exon 13 in four donors (Donors 6, 8, 15, and 18).…”

Role of CD36, the Macrophage Class B Scavenger Receptor, in Atherosclerosis

“…39 This reduced binding and uptake of Ox-LDL was expected based on previous data in human macrophages. A genetic polymorphism in the CD36 gene has been identified in an Asian population 40 and shown to result in deficient expression of CD36 (NAK aphenotype). Monocyte-derived macrophages isolated from these patients bound 40% less Ox-LDL and accumulated 40% less cholesterol ester than did cells derived from normal controls, further implicating CD36 as a physiological OxLDL receptor.…”

Neonatal isoimmune thrombocytopenia caused by type I CD36 deficiency having novel splicing isoforms of the CD36 gene

“…In addition, to elucidate why splicing isoforms occurred, we examined the sequence of CD36 DNA besides exons 4 and 9. We could not detected genomic abnormality except for a single-nucleotide substitution, intervening sequence 3-6;t fi c. This mutation was a single-nucleotide polymorphism (SNP) (13).…”

“…This resulted in absence of CD36 surface protein on platelets and monocytes. Nine mutations of the CD36 gene were previously reported (12)(13)(14)(15)(16). Of the reported alterations, there were three kinds of exon skipping with intraexonic mutation (8,13,16).…”