Brothers with novel compound heterozygous mutations in COL27A1 causing dental and genital abnormalities.

COL27A1 encodes a collagen type XXVII alpha 1 chain. It is the product of this gene that provides the structural support of connective tissue and is reported to be the causative gene of Steel syndrome (OMIM #615155). The primary symptoms of patients with this defect are consistent with systemic bone disease; however, recent reports note findings of intellectual disability and hearing loss. In this study, we identified novel COL27A1 compound heterozygous variants in two brothers with rhizomelia and congenital hip dislocation as well as dental and genital abnormalities that have not yet been reported in Steel syndrome. This variant, of maternal origin, caused an amino acid substitution of arginine for glycine, c.2026G>C or p.G676R, in the collagen helix domain, which is assumed to damage the structure of the helix. The paternally transmitted variant, c.2367G>A, is located at the 3' end of exon 12, and cDNA analysis revealed a splicing alteration. These novel, compound heterozygous COL27A1 variants might indicate an association of the gene with tooth and genital abnormalities.

Evaluation of Face2Gene using facial images of patients with congenital dysmorphic syndromes recruited in Japan.

An increasing number of genetic syndromes present a challenge to clinical geneticists. A deep learning-based diagnosis assistance system, Face2Gene, utilizes the aggregation of "gestalt," comprising data summarizing features of patients' facial images, to suggest candidate syndromes. Because Face2Gene's results may be affected by ethnicity and age at which training facial images were taken, the system performance for patients in Japan is still unclear. Here, we present an evaluation of Face2Gene using the following two patient groups recruited in Japan: Group 1 consisting of 74 patients with 47 congenital dysmorphic syndromes, and Group 2 consisting of 34 patients with Down syndrome. In Group 1, facial recognition failed for 4 of 74 patients, while 13-21 of 70 patients had a diagnosis for which Face2Gene had not been trained. Omitting these 21 patients, for 85.7% (42/49) of the remainder, the correct syndrome was identified within the top 10 suggested list. In Group 2, for the youngest facial images taken for each of the 34 patients, Down syndrome was successfully identified as the highest-ranking condition using images taken from newborns to those aged 25 years. For the oldest facial images taken at ≥20 years in each of 17 applicable patients, Down syndrome was successfully identified as the highest- and second-highest-ranking condition in 82.2% (14/17) and 100% (17/17) of the patients using images taken from 20 to 40 years. These results suggest that Face2Gene in its current format is already useful in suggesting candidate syndromes to clinical geneticists, using patients with congenital dysmorphic syndromes in Japan.

Three brothers with a nonsense mutation in KAT6A caused by parental germline mosaicism.

Mutations in KAT6A, encoding a member of the MYST family of histone acetyl-transferases, were recently reported in patients with a neurodevelopmental disorder (OMIM: #616268, autosomal dominant mental retardation-32). In this report, we describe three siblings with intellectual disability (ID) or global developmental delay and a KAT6A heterozygous nonsense mutation, i.e., c.3070C>T (p.R1024*, ENST00000406337; chr8:41795056G>A on hg19). This mutation was identified by whole-exome sequencing of all three siblings but not in a healthy sibling. The mutation was not detected in the peripheral blood of their parents, suggesting the existence of parental germline mosaicism. The primary symptoms of our patients included severe to profound ID or global developmental delay, including speech delay with craniofacial dysmorphism; these symptoms are consistent with symptoms previously described for patients with KAT6A mutations. Although several features are common among patients with KAT6A mutations, the features are relatively nonspecific, making it difficult to establish a clinical entity based on clinical findings alone. To the best of our knowledge, this is the first report of cases with a KAT6A mutation in an Asian population and these cases represent the first reported instances of germline mosaicism of this disease.

DOC2b is a SNARE regulator of glucose-stimulated delayed insulin secretion.

Insulin secretion is precisely regulated by blood glucose with unique biphasic pattern. The regulatory mechanism of the second-phase insulin release is unclear. In this study, we report that DOC2b (double C2 domain protein isoform b), a SNARE related protein, was associated with insulin vesicles and translocated to plasma membrane within several minutes upon high-glucose stimulation followed by an interaction with syntaxin4, but not syntaxin1. This binding specificity and the time course of DOC2b translocation were suitable for the regulation of second-phase insulin release. Increased DOC2b expression enhanced glucose-stimulated insulin secretion. In contrast, silencing DOC2b inhibited delayed release of insulin, without affecting rapid (approximately 7min) phase secretion. Interestingly, DOC2b had no effects on KCl-triggered insulin release. These data suggest that DOC2b may be a regulator for delayed (second-phase) insulin secretion in MIN6 cells.

Identification of Glypican3 as a novel GLUT4-binding protein.

Insulin stimulates glucose uptake in fat and muscle primarily by stimulating the translocation of vesicles containing facilitative glucose transporters, GLUT4, from intracellular compartments to the plasma membrane. Although cell surface externalization of GLUT4 is critical for glucose transport, the mechanism regulating cell surface GLUT4 remains unknown. Using a yeast two-hybrid screening system, we have screened GLUT4-binding proteins, and identified a novel glycosyl phosphatidyl inositol (GPI)-linked proteoglycan, Glypican3 (GPC3). We confirmed their interaction using immunoprecipitation and a GST pull-down assay. We also revealed that GPC3 and GLUT4 to co-localized at the plasma membrane, using immunofluorescent microscopy. Furthermore, we observed that glucose uptake in GPC3-overexpressing adipocytes was increased by 30% as compared to control cells. These findings suggest that GPC3 may play roles in glucose transport through GLUT4.

Pure red-cell aplasia caused by the antibody to recombinant erythropoietin, epoetin-beta, in a Japanese patient with chronic renal failure.

A 68-year-old male with chronic renal failure and anemia received recombinant human erythropoietin (rHuEPO), epoetin beta, for approximately 1 year. Although the agent was initially effective for improving anemia, anemia refractory to EPO administration appeared and then worsened later, and pure red-cell aplasia (PRCA) was diagnosed. Anti-EPO antibody was detected by radioimmunoprecipitation (RIP) assay in the patient's serum. The antibody inhibited the proliferation of EPO-dependent cell line in a dose-dependent manner neutralizing EPO activity. The antibody also reacted with the other epoetin alfa products. The antibody did not recognize the carbohydrate moieties or denatured epoetin beta. The result suggested that the antibody recognized the conformational epitope of epoetin beta peptide molecule. Withdrawal of EPO and administration of cyclosporine decreased the titers of antibody; however, erythroid progenitor has not yet regenerated although the requirement for red blood cell transfusion is decreasing.

[Hairy cell leukemia, Japanese variant, successfully treated with cladribine].

A 67-year-old male was admitted because of lymphocytosis and huge splenomegaly. Abnormal lymphocytes had cytoplasmic hairy projections and were negative for tartrate-resistant acid phosphatase staining. The bone marrow aspirate contained many lymphocytes with the same morphology. Flow cytometric analysis revealed an increase in IgM and kappa positive B cells. They were positive for CD11c, CD19, CD20 and FMC7, and negative for CD5, CD10 and CD25. The patient was diagnosed as having hairy cell leukemia, Japanese variant. Initially interferon-alpha was administered for a month, decreasing the numbers of leukemic cells but with little effect on splenomegaly. Subsequent administration of cladribine (0.09 mg/kg, 7 days) showed a remarkable effect, and the patient has been in complete remission for 8 months.

Gamma/delta T cell lymphoma.

A 54-year-old woman complained of fever and hepato-splenomegaly. The pathological findings of a liver biopsy specimen revealed the infiltration of lymphocytes in the sinusoids and that of the laparoscopically resected spleen revealed the infiltration of lymphocytes in the red pulp, which was positive for CD3, CD43, CD45RO and T-cell intracellular antigen-1 (TIA-1) and was negative for betaF1, while the white pulp was spared. Genetic analysis of the spleen cells revealed the rearrangement of T-cell receptor (TCR) Cbeta1, Jdelta1 and Jgamma. Epstein-Barr virus (EBV) genomic DNA was detected in the spleen cells. Atypical lymphocytes appeared in the peripheral blood and bone marrow, chromosomal analysis revealed del (13) (q12 q14), trisomy 8 and breakage of RB gene. Elevated level of serum vascular endothelial growth factor (VEGF) was observed. Hepatosplenic gammadelta T cell lymphoma (GDTL) was diagnosed. The patient was treated with chemotherapy by cyclophosphamide, hydroxydoxorubicin, vincristine and prednisolone (CHOP), however, it was ineffective, and the patient died of hemorrhage from the lymphoma involvement of the intestine 5 months after the onset of disease.

Two cases of acute myeloblastic leukemia evolving from aplastic anemia.

Two cases of acute myeloblastic leukemia (AML) evolving from aplastic anemia are presented. The first case was diagnosed 18 years ago, and treatment with bolus methylprednisolone, prednisolone, and androgens resulted in partial hematological response. Severe pancytopenia recurred, and AML M0 by French-American-British classification developed. The second case was diagnosed 7 years ago. The patient had HLA DRB1*1501, and treatment with granulocyte colony-stimulating factor (G-CSF), cyclosporine, and methenolone resulted in complete hematological response. Thrombocytopenia recurred and did not respond to cyclosporine and methenolone or to later treatment with antithymocyte globulin, and AML M1 developed. Cytogenetic studies demonstrated 7q- in the first patient and +8 in the second patient. No mutations of N-ras or p53 were observed in either patient. These patients were treated with cytosine arabinoside, aclacinomycin, and G-CSF (CAG) chemotherapy, and the number of leukemic cells decreased substantially. However, pancytopenia after CAG chemotherapy persisted, and the first patient died of pneumonia and the second patient of cerebral hemorrhage.

Therapy-related erythroleukemia caused by the administration of UFT and mitomycin C in a patient with colon cancer.

A 54-year-old man with colon cancer underwent hemicolectomy. He received postoperative adjuvant chemotherapy with UFT (tegafur/uracil at a 1 : 4 molar ratio) and mitomycin C (MMC) for 3 years. Three years and 4 months after the start of chemotherapy, pancytopenia was noted. Bone marrow aspiration smear demonstrated an increased number of immature erythroblasts, including megaloblasts and myeloblasts. Chromosomal analysis demonstrated structural and numerical abnormalities of 5, 7, 15, and 17. Therapy-related erythroleukemia, acute myeloid leukemia (AML), M6, was diagnosed. The disease progressed after 5 months, and the patient was received chemotherapy with cytosine arabinoside, aclacinomycin, and granulocyte colony-stimulating factor (CAG), and showed a partial hematological response. Careful monitoring for the generation of therapy-related leukemia is needed when UFT and MMC are used for postoperative adjuvant chemotherapy for colorectal cancer.