Haplotype analysis and targeted next-generation resequencing allowed us to identify a mutation in the KIF23 gene and to show its association with an autosomal dominant form of congenital dyserythropoietic anemia type III (CDA III). The region at 15q23 where CDA III was mapped in a large Swedish family was targeted by array-based sequence capture in a female diagnosed with CDA III and her healthy sister. Prioritization of all detected sequence changes revealed 10 variants unique for the CDA III patient. Among those variants, a novel mutation c.2747C>G (p.P916R) was found in KIF23, which encodes mitotic kinesin-like protein 1 (MKLP1). This variant segregates with CDA III in the Swedish and American families but was not found in 356 control individuals. RNA expression of the 2 known splice isoforms of KIF23 as well as a novel one lacking the exons 17 and 18 was detected in a broad range of human tissues. RNA interference–based knock-down and rescue experiments demonstrated that the p.P916R mutation causes cytokinesis failure in HeLa cells, consistent with appearance of large multinucleated erythroblasts in CDA III patients. We conclude that CDA III is caused by a mutation in KIF23/MKLP1, a conserved mitotic kinesin crucial for cytokinesis.
13 April 2010 in American Journal of Medical Genetics Part A
Prognostic factors were studied in a series of 211 acute myeloid leukaemia (AML) patients over 60 years of age, treated at a single centre. The patients were allocated into three risk groups based on cytogenetics, occurrence of antecedent haematological disorder and leucocyte count. Only 3% had low‐risk features, 39% had intermediate‐ and 58% had adverse‐risk features. Complete remission (CR) was achieved in 43% of all patients. In multivariate analyses, the number of cycles needed to achieve CR and the risk group were significantly associated with the duration of CR. Median survival time for the entire cohort of patients was only 107 d. Advanced age, low induction treatment intensity, treatment during earlier years and adverse‐risk group were associated with shorter overall survival times. Risk group classification may help selection of elderly patients with a good chance of benefiting from intensive treatment to actually receive such treatment, while sparing others with a low probability of survival benefit from toxic treatment. Low intensity induction treatment reduces the chance of obtaining complete remission, produces inferior survival times and should consequently be avoided when the aim is to obtain complete remission. In elderly AML patients, introducing age and re‐evaluation of intermediate and good prognosis patients regarding response to induction treatment may improve the risk group classification.
Corneal dystrophies are a clinically and genetically heterogeneous group of inherited disorders that bilaterally affect corneal transparency. They are defined according to the corneal layer affected and by their genetic cause. In this study, we identified a dominantly inherited epithelial recurrent erosion dystrophy (ERED)-like disease that is common in northern Sweden. Whole-exome sequencing resulted in the identification of a novel mutation, c.2816C>T, p.T939I, in the COL17A1 gene, which encodes collagen type XVII alpha 1. The variant segregated with disease in a genealogically expanded pedigree dating back 200 years. We also investigated a unique COL17A1 synonymous variant, c.3156C>T, identified in a previously reported unrelated dominant ERED-like family linked to a locus on chromosome 10q23-q24 encompassing COL17A1. We show that this variant introduces a cryptic donor site resulting in aberrant pre-mRNA splicing and is highly likely to be pathogenic. Bi-allelic COL17A1 mutations have previously been associated with a recessive skin disorder, junctional epidermolysis bullosa, with recurrent corneal erosions being reported in some cases. Our findings implicate presumed gain-of-function COL17A1 mutations causing dominantly inherited ERED and improve understanding of the underlying pathology.