Emergence and evolution of Plasmodium falciparum histidine-rich protein 2 and 3 deletion mutant parasites in Ethiopia

Malaria diagnostic testing in Africa is threatened by Plasmodium falciparum parasites lacking histidine-rich protein 2 (pfhrp2) and 3 (pfhrp3) genes. Among 12,572 subjects enrolled along Ethiopia’s borders with Eritrea, Sudan, and South Sudan and using multiple assays, we estimate HRP2-based rapid diagnostic tests would miss 9.7% (95% CI 8.5-11.1) of falciparum malaria cases due to pfhrp2 deletion. Established and novel genomic tools reveal distinct subtelomeric deletion patterns, well-established pfhrp3 deletions, and recent expansion of pfhrp2 deletion. Current diagnostic strategies need to be urgently reconsidered in Ethiopia, and expanded surveillance is needed throughout the Horn of Africa.

Accurate, Fast and Cost-Effective Diagnostic Test for Monosomy 1p36 Using Real-Time Quantitative PCR

Monosomy 1p36 is considered the most common subtelomeric deletion syndrome in humans and it accounts for 0.5–0.7% of all the cases of idiopathic intellectual disability. The molecular diagnosis is often made by microarray-based comparative genomic hybridization (aCGH), which has the drawback of being a high-cost technique. However, patients with classic monosomy 1p36 share some typical clinical characteristics that, together with its common prevalence, justify the development of a less expensive, targeted diagnostic method. In this study, we developed a simple, rapid, and inexpensive real-time quantitative PCR (qPCR) assay for targeted diagnosis of monosomy 1p36, easily accessible for low-budget laboratories in developing countries. For this, we have chosen two target genes which are deleted in the majority of patients with monosomy 1p36:PRKCZandSKI. In total, 39 patients previously diagnosed with monosomy 1p36 by aCGH, fluorescentin situhybridization (FISH), and/or multiplex ligation-dependent probe amplification (MLPA) all tested positive on our qPCR assay. By simultaneously using these two genes we have been able to detect 1p36 deletions with 100% sensitivity and 100% specificity. We conclude that qPCR ofPRKCZandSKIis a fast and accurate diagnostic test for monosomy 1p36, costing less than 10 US dollars in reagent costs.

Molecular analyses in Indonesian individuals with intellectual disability and microcephaly

Background Intellectual disability (ID) often coincides with anabnormal head circumference (HC). Since the HC is a reflectionof brain size, abnormalities in HC may be a sign of a brain anomaly.Although microcephaly is often secondary to ID, hereditary(autosomal recessive) forms of primary microcephaly (MCPH)exist that result in ID.Objective To investigate mutations in MCPH genes in patientswith ID and microcephaly.Methods From a population of 527 Indonesian individuals withID, 48 patients with microcephaly (9.1 %) were selected. Thesepatients were previously found to be normal upon conventionalkaryotyping, fragile X mental retardation 1 (FMRl) gene analysis,subtelomeric deletion, and duplication multiplex ligationdependentprobe amplification (MLPA). Sanger sequencing forabnormal spindle-like microcephaly-associated (ASPM) and WDrepeat domain 62 (WDR62) was performed in all 48 subjects, whilesequencing for microcephalin (MCPHl), cyclin-dependent kinase5 (CDK5) regulatory subunit-associated protein 2 (CD5KRAP2) ,centromere protein} (CENPJ), and SCUfALl interrupting locus(STIL) was conducted in only the subjects with an orbitofrontalcortex (OFC) below -4 SD.Results In all genes investigated, 66 single nucleotide polymorphisms(SNPs) and 15 unclassified variants which were predictedas unlikely to be pathogenic (lN2), were identified. Possiblepathogenic variants (lN3) were identified in ASPM. However,since none of the patients harboured compound heterozygouslikely pathogenic mutations, no molecular MCPH diagnosis couldbe established. Interestingly, one of the patients harboured thesame variants as her unaffected monozygotic twin sister, indicatingthat our cohort included a discordant twin.Conclusions This study is the first to investigate for possible geneticcauses ofMCPH in the Indonesian population. The absenceof causative pathogenic mutations in the MCPH genes tested may originate from several factors. The identification of UV2and UV3 variants as well as the absence of causative pathogenicmutations calls for further investigations.

Prenatal Diagnosis of 4p and 4q Subtelomeric Microdeletion in De Novo Ring Chromosome 4

Ring chromosomes are unusual abnormalities that are observed in prenatal diagnosis. A 23-year-old patient (gravida 1, para 0) referred for amniocentesis due to abnormal maternal serum screening result in the 16th week of second pregnancy. Cytogenetic analysis of cultured amniyotic fluid cells revealed out ring chromosome 4. Both maternal and paternal karyotypes were normal. Terminal deletion was observed in both 4p and 4q arms of ring chromosome 4 by fluorescence in situ hybridization (FISH). However deletion was not observed in the WHS critical region of both normal and ring chromosome 4 by an additional FISH study. These results were confirmed by means of array-CGH showing terminal deletions on 4p16.3 (130 kb) and 4q35.2 (2.449 Mb). In the 21th week of pregnancy, no gross anomalia, except two weeks symmetric growth retardation, was present in the fetal ultrasonographic examination. According to our review of literature, this is the first prenatal case with 4p and 4q subtelomeric deletion of ring chromosome 4 without the involvement of WHS critical region. Our report describes the prenatal case with a ring chromosome 4 abnormality completely characterized by array-CGH which provided complementary data for genetic counseling of prenatal diagnosis.