BACKGROUNDFanconi anemia is a severe congenital disorder associated with mutations in a cluster of genes responsible for DNA repair. Arriving at an accurate and timely diagnosis can be difficult in cases of Fanconi anemia with atypical clinical features. It is very important to increase the rate of accurate diagnosis for such cases in a clinical setting. The purpose of this study is to explore the clinical diagnosis of Fanconi anemia in children with atypical clinical features.

METHODSSix cases of Fanconi anemia with atypical clinical features were enrolled in the study, and their clinical features were recorded, their FANCA gene transcription was assessed by RT-PCR, and FANCA mutations and the ubiquitination of FANCD2 protein were analyzed using DNA sequencing and western blotting respectively.

RESULTSAll six cases showed atypical clinical features including no apparent deformities, lack of response to immune therapy, and progressively increasing bone marrow failure. They also have significantly increased fetal hemoglobin, negative mitomycin-induced fracture test results, and carry a FANCA gene missense mutation. Single protein ubiquitination of FANCD2 was not observed in those patients.

CONCLUSIONThe combination of clinical features, FANCA pathogenic gene mutation genotype and the absence of FANCD2 protein ubiquitination are helpful in the accurate and timely diagnosis of Fanconi anemia in children.

Child ; Child, Preschool ; Fanconi Anemia ; diagnosis ; genetics ; metabolism ; Fanconi Anemia Complementation Group D2 Protein ; genetics ; metabolism ; Female ; Humans ; Male ; Mutation ; Ubiquitination

Fanconi anemia (FA) is a rare genetic disorder affecting multiple body systems. Genetic testing, including prenatal testing, is a prerequisite for the diagnosis of many clinical conditions. However, genetic testing is complicated for FA because there are often many genes that are associated with its development, and large deletions, duplications, or sequence variations are frequently found in some of these genes. This study describes successful genetic testing for molecular diagnosis, and subsequent prenatal diagnosis, of FA in a patient and his family in Korea. We analyzed all exons and flanking regions of the FANCA, FANCC, and FANCG genes for mutation identification and subsequent prenatal diagnosis. Multiplex ligation-dependent probe amplification analysis was performed to detect large deletions or duplications in the FANCA gene. Molecular analysis revealed two mutations in the FANCA gene: a frameshift mutation c.2546delC and a novel splice-site mutation c.3627-1G>A. The FANCA mutations were separately inherited from each parent, c.2546delC was derived from the father, whereas c.3627-1G>A originated from the mother. The amniotic fluid cells were c.3627-1G>A heterozygotes, suggesting that the fetus was unaffected. This is the first report of genetic testing that was successfully applied to molecular diagnosis of a patient and subsequent prenatal diagnosis of FA in a family in Korea.
Base Sequence ; Child, Preschool ; Exons ; Fanconi Anemia/*diagnosis/genetics ; Fanconi Anemia Complementation Group A Protein/genetics ; Fanconi Anemia Complementation Group C Protein/genetics ; Fanconi Anemia Complementation Group G Protein/genetics ; Female ; Frameshift Mutation ; Genetic Testing ; Heterozygote ; Humans ; Karyotyping ; Male ; Pregnancy ; Prenatal Diagnosis ; RNA Splice Sites ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA

OBJECTIVETo provide prenatal diagnosis for a pregnant woman who had given birth to a child with Fanconi anemia with combined next-generation sequencing (NGS) and Sanger sequencing.

METHODSFor the affected child, potential mutations of the FANCA gene were analyzed with NGS. Suspected mutation was verified with Sanger sequencing. For prenatal diagnosis, genomic DNA was extracted from cultured fetal amniotic fluid cells and subjected to analysis of the same mutations.

RESULTSA low-frequency frameshifting mutation c.989_995del7 (p.H330LfsX2, inherited from his father) and a truncating mutation c.3971C>T (p.P1324L, inherited from his mother) have been identified in the affected child and considered to be pathogenic. The two mutations were subsequently verified by Sanger sequencing. Upon prenatal diagnosis, the fetus was found to carry two mutations.

CONCLUSIONThe combined next-generation sequencing and Sanger sequencing can reduce the time for diagnosis and identify subtypes of Fanconi anemia and the mutational sites, which has enabled reliable prenatal diagnosis of this disease.

Adult ; Base Sequence ; Child, Preschool ; DNA Mutational Analysis ; Fanconi Anemia ; diagnosis ; genetics ; Fanconi Anemia Complementation Group A Protein ; genetics ; Female ; Fetal Diseases ; diagnosis ; genetics ; High-Throughput Nucleotide Sequencing ; Humans ; Male ; Molecular Sequence Data ; Mutation ; Polymorphism, Single Nucleotide ; Pregnancy ; Prenatal Diagnosis

OBJECTIVEFanconi anemia (FA) is characterized by bone marrow failure, congenital abnormalities and predisposition to neoplasia. Hypersensitivity of FA cells to the clastogenic effect of mitomycin C (MMC) provides a unique marker for the diagnosis before the beginning of hematological manifestations. The aim of this study was to evaluate the relationship between Single-Cell Gel Electrophoresis (SCGE) and mitomycin C-induced chromosomal breakage in children with FA.

METHODBetween January 2007 and June 2011, 248 children (< 15 years) with hypocytosis were included. Chromosomal breakage was induced by MMC 0 ng/ml, 40 ng/ml, and 80 ng/ml. SCGE was performed at the same time. We analyzed the results of the two methods and compared with each other. The receiver operating characteristic (ROC) curve was used to evaluate the parameters in SCGE.

RESULTSeventeen patients were diagnosed as FA and 231 as non-FA. Chromosomal breakage was found to be significantly higher in FA patients [(32.2 ± 4.8)%] than non-FA [(19.9 ± 3.0)%] and controls[(21.6 ± 4.8)%] when induced by MMC 80 ng/ml. The parameters of SCGE were significantly different between FA patients and non-FA or controls. All the parameters were rectilinearly correlated with MMC (P = 0.000). The most closely correlated parameter was the rate of comet cell (r = 0.848, P = 0.000). The results of ROC curves suggested the comet cell rate (0.999) was more important.

CONCLUSIONSCGE might be used to discriminate between FA and non-FA individuals. The relationship between SCGE and MMC-induced chromosomal breakage was significant. The rate of comet cell was the important parameter.

Adolescent ; Anemia, Aplastic ; diagnosis ; Case-Control Studies ; Child ; Child, Preschool ; Chromosomal Instability ; Chromosome Breakage ; drug effects ; Comet Assay ; methods ; DNA Damage ; Diagnosis, Differential ; Fanconi Anemia ; diagnosis ; genetics ; Female ; Humans ; Infant ; Male ; Mitomycin ; pharmacology ; Mosaicism ; Pancytopenia ; diagnosis ; genetics ; ROC Curve

OBJECTIVETo enrich our national database with data of rare diseases by analyzing molecular diagnosis and hematopoietic stem cell transplantation (HSCT) in children with inherited bone marrow failure syndromes (IBMFS).

METHODNext-generation sequencing (NGS)-based genetic diagnosis panel was applied for the clinical diagnosis and management of IBMFS. Retrospective analysis was performed on clinical and genetic data of 17 consecutive children who received HSCT over a long time interval (November. 2005-June 2015).

RESULTThree patients were diagnosed only by clinical manifestation before 2012. After that NGS-based genetic diagnosis panel was used to identify IBMFS-related genes in 12/14.IBMFS patients (except two Diamond-Blackfan anemia (DBA) patients). Two Fanconi anemia (FA) patients were confirmed to be new variations through family-genotype-analysis and 3 families accepted prenatal diagnosis to avoid birth of affected fetuses. Seventeen IBMFS patients (10 FA,5 DBA and 2 dyskeratosis congenital (DKC)) were treated with HSCT from matched sibling donors (n=2), matched unrelated donors (n=8) or mismatched unrelated donors (n=7). The source of stem cells for transplantation included peripheral blood (n=12) and cord blood (n=5). With regard to the conditioning regimens, FA and DKC patients received fludarabine-based reduced intensity conditioning, while DBA patients received classical busulfan-based myeloablative conditioning. Median age at the time of HSCT was 36 months (7-156 months). The number of infused mononuclear cells and CD34⁺ cells was (10.6 ± 6.7) × 10⁸ and (5.9 ± 7.0) × 10⁶ per kilogram of recipient body weight, respectively. The median number of days to neutrophil recovery was 13 days after HSCT (range: 10-19 days). Platelet recovery was faster in the PBSCT group than in the CBT group ((16.3 ± 6.0) days vs. (30.0 ± 17.1) days,t=-2.487,P=0.026). During a median follow-up of 17 months (range: 2-114 months), except one FA patient who was transplanted with HLA-matched unrelated cord blood (CB) died from pneumonia and heart failure because of engraftment failure, other 16 children are alive after the successful HSCT. The failure-free survival rate of the patients three years after HSCT was 94%.

CONCLUSIONNGS-based molecular diagnosis technology and effective HSCT have significantly facilitated the treatment of children with IBMFS in our country, and our national database about this rare disease is to be further exploited.

Anemia, Aplastic ; Anemia, Diamond-Blackfan ; therapy ; Bone Marrow Diseases ; Child ; Dyskeratosis Congenita ; therapy ; Fanconi Anemia ; therapy ; Fetal Blood ; Hematopoietic Stem Cell Transplantation ; Hemoglobinuria, Paroxysmal ; diagnosis ; genetics ; therapy ; Humans ; Retrospective Studies ; Siblings ; Survival Rate ; Transplantation Conditioning ; Unrelated Donors ; Vidarabine ; analogs & derivatives ; therapeutic use