Despite their apparently good prognosis B15% of high hyperdiploid (HD) childhood acute lymphoblastic leukemia (ALL) cases relapse. To search for responsible risk factors we determined copy number aberrations as well as copy neutral loss of heterozygosity (LOH) in 13 matched diagnosis and relapse samples and added the data of the only three available cases from the literature. Deletions and copy neutral LOH in 3 and 2 of the 16 cases directed us to the histone-modifying CREB-binding protein (CREBBP) gene, whose functional impairment is implicated in drug resistance. We therefore screened all samples for mutations in this gene and discovered 9 acquired sequence mutations in 7/16 cases, leading to an overall frequency of somatic CREBBP aberrations in HD ALL relapse cases of 63% that is considerably higher than that of the reported, mainly non-HD ALL (18.3%). Moreover, mutations in HD cases occur almost exclusively in the HAT domain (8/9; 89%). Hot spot mutations are present at diagnosis in 18.8% of relapsing HD ALL cases but in none of 40 respective cases remaining in long-term remission. Thus, the particular high incidence of CREBBP mutations in relapse-prone HD ALL cases could eventually be exploited for refined risk stratification and customized treatment in this genetic subgroup.

Hereditary and sporadic medullary thyroid carcinoma (MTC) are closely associated with RET proto-oncogene mutations. However, the role of additional changes in the tumor genomes remains unclear. Our objective was the identification of chromosomal regions involved in MTC tumorigenesis and to assess their significance by using MTC-derived cell lines. We used array-CGH (comparative genomic hybridization) to map chromosomal imbalances in 52 primary tumors and ten metastases. Eleven tumors (11/52, 21%) were hereditary and 41 (41/52, 79%) were sporadic. Among the latter, 15 tumors (15/41, 37%) harbored RET mutations. Furthermore, we characterized five MTC cell lines in detail and evaluated the tumorigenicity by severe combined immunodeficiency (SCID)-mouse experiments. Most MTCs had only few copy number changes, and losses of chromosomes 1p, 4q, 19p and 22q were observed most frequently. The number of chromosomal aberrations increased in metastases. Twenty-three percent (12/52) of the primary tumors did not even show any chromosomal gains and losses. We injected three cell lines (two of these were without chromosomal changes and pathogenic RET mutations) into immune deficient SCID mice, and in each case, we observed rapid tumor growth at the injection sites. Our data suggest that MTCs-in contrast to most other tumor entities-do not acquire a multitude of genomic imbalances. SCID mouse experiments performed with chromosomally normal cell lines and without RET mutations suggest that presently unknown submicroscopic genomic changes are sufficient in MTC tumorigenesis.Human medullary thyroid carcinoma (MTC) is a calcitoninproducing tumor originating from the parafollicular C-cells. It constitutes about 5-8% of all thyroid cancers and may occur sporadic (70-80% of cases) or hereditary (20-30%). 1Hereditary MTC is inherited in an autosomal-dominant pattern, either as familial MTC (FMTC) without other endocrinopathies or as part of multiple endocrine neoplasia syndrome type 2A (MEN-2A), or in multiple endocrine neoplasia type 2B (MEN-2B). 2As the disease may develop over many years without clinical signs, lymph node metastasis are documented in more than 50% of patients, and distant metastasis are found in at least in one quarter of patients at the time of diagnosis. With 5-and 10-year survival reported at 86% and 78%, respectively, prognosis is less favorable than for follicular cellderived carcinomas. Patients with distant metastases have only a 35% survival after 5 years. MTC, both in patients and in preclinical models, is resistant to chemotherapy and radiation therapy. Surgical removal of all malignant tissue is the only potentially curative treatment in localized disease.1 Management guidelines for treatment of MTC were recently published by the American Thyroid Association. 3MTC is closely associated with mutations in the REarranged during Transfection (RET) proto-oncogene in chromosome 10q11.2. The hereditary variants MEN-2/FMTC are associated with activating germline point mutations in the RET proto-oncogene and near...

We describe the second patient with anionic exchanger 1/band 3 null phenotype (band 3 null ), which was caused by a novel nonsense mutation c.1430C>A (p.Ser477X) in exon 12 of SLC4A1. We also update on the previous band 3 null patient, thereby elucidating the physiological implications of total loss of AE1/band 3. Besides transfusion-dependent severe hemolytic anemia and complete distal renal tubular acidosis, dyserythropoiesis was identified in the band 3 null patient, suggesting a role for band 3 in erythropoiesis. Moreover, we also, for the first time, report that long-term survival is possible in band 3 null patients.

Thiamine-responsive megaloblastic anemia (TRMA) is a rare disorder typically characterized by megaloblastic anemia, non-type I diabetes and sensorineural deafness. It is caused by various mutations in the SLC19A2 gene that impair the encoded thiamine transporter. So far, only 70 affected individuals mainly from consanguineous families of Middle and Far Eastern origin with a wide spectrum of signs and symptoms, variable onset of disease, and primarily homozygote mutations in SLC19A2 have been reported. We present the first genuine central European descendent with combined heterozygote mutations in SLC19A2, an Austrian boy suffering from pancytopenia and non-type I diabetes. Both manifestations resolved completely under continuous oral thiamine supplementation. Our observation underlines that despite its rarity, TRMA must be considered as an important differential diagnosis in native central European patients with suggestive signs and symptoms. An early molecular genetic verification of the diagnosis provides a sound basis for a successful and simple treatment that helps to prevent severe sequelae.

We report two children with severe chronic hemolytic anemia, the cause of which was difficult to establish because of transfusion dependency. Reduced erythrocyte pyruvate kinase activity in their asymptomatic parents provided the diagnostic clues for mutation screening of the PKLR gene and revealed that one child was a compound heterozygote of a novel paternally derived 5-bp deletion in the promoter region (c.-88_-84delTCTCT) and a maternally derived missense mutation in exon nine (c.1174G>A; p.Ala392Thr). The second child was a compound heterozygote of two novel missense mutations, namely a paternally derived exon ten c.1381G>A (p.Glu461Lys) and a maternally derived exon seven c.907-908delCC (p.Pro303GlyfsX12) variant.