Oral-facial-digital syndrome with retinal abnormalities: Report of a new case

Smith-Magenis syndrome (SMS) is a multiple congenital anomalies/mental retardation syndrome associated with deletion of band p11.2 of chromosome 17. The deletion is typically detected by high-resolution cytogenetic analysis of chromosomes from peripheral lymphocytes. Fluorescence in situ hybridization (FISH) has been previously used to rule out apparent mosaicism for del(17)(p11.2p11.2) indicated by routine cytogenetics. We now report mosaicism for del(17)(p11.2p11.2) in a child with SMS. The mosaicism had gone undetected during previous routine cytogenetic analysis. FISH analysis of peripheral lymphocytes as well as immortalized lymphoblasts using markers from 17p11.2 revealed that approximately 60% of cells carried the deletion. To our knowledge, this is the first case of SMS associated with mosaicism for del(17)(p11.2p11.2). © 1996 Wiley-Liss, Inc.     

Kallmann syndrome associated with complex chromosome rearrangement

We report on a male with Kallmann syndrome (KS) and an apparently balanced complex chromosome rearrangement (CCR): 46,XY,t(3;9)(9;12)(q13.2;q21.2p13;q15). This is the first known report of a CCR in the KS and the second reported case of a definitive autosomal chromosome abnormality with KS. Possible relationships between the cytogenetic abnormality and KS are discussed. © 1993 Wiley-Liss, Inc.     

Scope of Alagille syndrome

We report clinical and cytogenetic findings of 4 children (2 boys and 2 girls) with the Smith–Magenis syndrome. All 4 patients had an interstitial deletion of 17p: del(17) (p11.2p11.2). Their clinical manifestations included brachycephaly, midface hypoplasia, prognathism, upper lip eversion, short and broad hands with short fingers, clinodactyly of the fifth fingers, fingertip pads, moderate mental retardation, and behavior problems. Analysis of the metacarpophalangeal pattern profiles in patient 2 showed progressive shortness from the metacarpals to the proximal, middle, and the distal phalanges. The finger-pads observed in all 4 patients have hitherto been noted in only one of 26 previously reported patients with the syndrome. These findings serve as a useful clue to the diagnosis of the syndrome.     

Gene for topoisomerase III maps within the Smith-Magenis syndrome critical region: Analysis of cell-cycle distribution and radiation sensitivity

Smith-Magenis syndrome (SMS) is caused by an interstitial deletion of chromosome band 17p11.2 averaging 4–5 Mb. This deletion is likely to contain a large number of genes, each of which could potentially contribute toward the clinical phenotype. We report that the gene for topoisomerase III (hTOP3) is commonly deleted in SMS patients and maps between D17S447 and D17S258 on the short arm of chromosome 17. Cellular studies of SMS patient lymphoblasts and their respective parental cell lines were undertaken to determine the consequences of haploinsufficiency of hTOP3. Our studies indicate that hemizygosity for hTOP3 does not appreciably affect cell-cycle kinetics or activation of ionizing radiation-sensitive cell-cycle checkpoints. Furthermore, the induction of apoptosis in response to ionizing radiation in SMS and parental cells was similar. Our studies suggest that haploinsufficiency of hTOP3 does not have a major impact on the behavior of cells from SMS patients and may not play a significant role in the SMS phenotype. Am. J. Med. Genet. 75:104–108, 1998. © 1998 Wiley-Liss, Inc.     

17p11.2p12 triplication and del(17)q11.2q12 in a severely affected child with dup(17)p11.2p12 syndrome

Multiple congenital anomalies/mental retardation syndromes due to genomic rearrangements involving chromosome 17p11.2 include deletion resulting in Smith-Magenis syndrome and a reciprocal duplication of the same region resulting in the 17p11.2 duplication syndrome. We present the clinical and molecular analysis of an 8-year-old male with a dup(17p11.2p12) who was evaluated for unusual severity of the phenotype. Fluorescent in situ hybridization (FISH) analysis not only confirmed the 17p duplication but also identified an approximately 25% mosaicism for tetrasomy 17p11.2p12. Whole-genome array comparative genomic hybridization (aCGH) was performed to identify other genomic rearrangements possibly contributing to the severe phenotype and the unusual features in the patient. The 17p duplication was determined by FISH and aCGH to encompass approximately 7.5 Mb, from COX10 to KCNJ12. An approximately 830 Kb deletion of 17q11.2q12, including exon 1 of an amiloride-sensitive cation channel neuronal gene, ACCN1, was also identified by aCGH; breakpoints of the deletion were confirmed by FISH. Sequencing the non-deleted allele of ACCN1 did not show any mutations. Western analysis of human tissue-specific proteins revealed that ACCN1 is expressed not only in the brain as previously reported but also in all tissues examined, including heart, liver, kidneys, and spleen. The large-sized 17p11.2p12 duplication, partial triplication of the same region, and the 17q11.2q12 deletion create a complex chromosome 17 rearrangement that has not been previously identified. This is the first case of triplication reported for this chromosome. Our study emphasizes the utility of whole-genome analysis for known cases with deletion/duplication syndromes with unusual or severe phenotypes.     

Unbalanced translocation (15;17)(q13;p13.3) with apparent Prader-Willi syndrome but without Miller-Dieker syndrome

We studied after death a 3-month-old girl whose karyotype was 45,XX, ? 15, ? 17, + der(17),t(15;17)(q13;p13.3) and thus combines abnormalities of chromosome 15 associated with the Prader-Willi syndrome and of chromosome 17 associated with the Miller-Dieker syndrome. This infant had several manifestations of the Prader-Willi syndrome in infancy but none of the Miller-Dieker syndrome. We propose that essentially no loss of 17p material has occurred and confirm previous reports that the critical region for the production of the Miller-Dieker phenotype is located subterminally in the 17p13.3 region.     

Prenatal diagnosis of Smith-Lemli-Opitz syndrome

The availability of markers for the 17p11.2 region has enabled the diagnosis of Smith-Magenis syndrome (SMS) by fluorescence in situ hybridization (FISH). SMS is typically associated with a discernible deletion of band 17p11.2 upon cytogenetic analysis at a resolution of 400–550 bands. We present a case that illustrates the importance of using FISH to confirm a cytogenetic diagnosis of del(17)(p11.2). Four independent cytogenetic analyses were performed with different conclusions. Results of low resolution analyses of amniocytes and peripheral blood lymphocytes were apparently normal, while high resolution analyses of peripheral blood samples in two laboratories indicated mosaicism for del(17)(p11.2). FISH clearly demonstrated a 17p deletion on one chromosome of all peripheral blood cells analyzed and ruled out mosaicism unambiguously. The deletion was undetectable by flow cytometric quantitation of chromosomal DNA content, suggesting that it is less than 2 Mb. We conclude that FISH should be used to detect the SMS deletion when routine chromosome analysis fails to detect it and to verify mosaicism. © 1995 Wiley-Liss, Inc.     

四例合并继发性der(9)t(9;22)(q34;q11)inv(9)(p22q34)异常的Ph阳性白血病的临床及分子遗传学研究

目的 探讨4例合并继发性der(9)t(9;22)(q34;q11)inv(9)(p22q34)异常的Ph阳性白血病的临床及分子遗传学特征.方法 应用骨髓细胞直接法或短期培养法制备染色体,经R显带进行核型分析.应用BCR/ABL双色双融合探针和9号染色体短臂及长臂涂染探针分别对4例伴有inv(9)(p22q34)的Ph阳性患者标本进行荧光原位杂交(fluorescence in situ hybridization,FISH)和染色体涂染分析.用逆转录PCR检测BCR/ABL融合基因转录本.结果 1例急性髓细胞白血病患者核型中有3种克隆,分别为正常细胞、t(9;22)(q34;q11)异常细胞、同时合并der(9)t(9;22)衍生克隆和Ph以及其它异常,即t(8;12)(q12;p11),der(9) t(9;22)inv(9) (p22q34),der(22)t(9;22)细胞.其余3例慢性粒细胞白血病患者均同时合并Ph和der(9)t(9;22)(q34;q11)inv(9)(p22q34).FISH结果显示,3例有1红1绿两个融合信号、2红2绿1个融合信号、且在中期分裂相中发现1红1绿荧光信号分别位于9号染色体的两端;另1例67.5％的细胞有2红1绿1融合信号,有1绿色信号的缺失即表明BCR基因的缺失.染色体涂抹检测发现4例患者均有9号染色体的倒位.逆转录PCR检测均为b3a2转录本.该继发异常既可发生于Ph阳性CML慢性期或急变期,也可发生于原发性Ph阳性AML.该异常核型可能与预后不良相关.结论 合并继发性der(9)t(9;22)(q34;q11)inv(9)(p22q34)异常的Ph阳性白血病是一种少见但可再现的Ph继发性异常,具有独特的临床和分子遗传学特点.     

A novel translocation t(10;17)(p13;q11.2) harboring two cryptic deletions identified by array‐CGH and characterized by SUZ12 overexpression in a patient with chronic thrombocytosis

No specific translocation is associated with myeloproliferative neoplasms (MPNs). However, an interstitial deletion involving subband 17q11.2 which includes the NF1 gene, although rare, is a recurrent aberration in several myeloid disorders including MPNs. For the first time, we report an acquired novel translocation involving 10p13 and 17q11.2 in a 62‐year‐old Caucasian female which was referred for investigation of chronic and persistent unexplained thrombocytosis. The patient had no history of hematological sequelae and genomic testing for JAK2, CALR, and MPL mutations were negative. She was subsequently diagnosed with a triple negative essential thrombocythemia. Array‐CGH analysis noted that the translocation harbored two cryptic deletions, one of which involved 17q11.2 encompassing the NF1 gene. One of the junction breakpoints involved the SUZ12 gene. Immunohistochemical assessment of the marrow trephine showed increased megakaryocytic expression of the SUZ12 protein, as well as EZH2 and Ki67; biochemical abnormalities suggestive of excess megakaryocytic hyperplasia. This novel translocation may affect the expression of SUZ12 and its downstream targets, and may represent a unique pathogenomic etiology which drives chronic thrombocytosis in essential thrombocythemia.     

EEC syndrome (ectrodactyly, ectodermal dysplasia and cleft lip/palate) with a balanced reciprocal translocation between 7q11.21 and 9p12 (or 7p11.2 and 9q12) in three generations

Familial cases (a grandfather, a father and a daughter) of the EEC syndrome (ectrodactyly, ectodermal dysplasia and cleft lip/palate) are reported. All of them have a balanced reciprocal translocation (46,XY or XX, t(7;9) (q11.21;p12) or (46,XY or XX, t(7;9) (p11.2;q12)), but no other members of the family have either the EEC syndrome or chromosome abnormalities. This indicates that one of the chromosome sites 7q11.21, 9p12, 7p11.2 and 9q12 is a candidate for gene locus of the EEC syndrome.     

Hyperlipidemia,insulin-dependent diabetes mellitus,and rapidly progressive diabetic retinopathy and nephropathy in Prader-Willi syndrome with del(15)(q11.2q13)

We report on a white man with Prader-Willi syndrome (PWS) and del(15)(q11.2q13), confirmed by fluorescence in situ hybridization (FISH), who had hyperlipidemia, insulin-dependent diabetes, and the early onset and rapid progression of diabetic retinopathy and nephropathy within 4 years after diagnosis of diabetes. The spectrum of glucose intolerance in patients with PWS is discussed, as well as those references which suggest that the prevalence of hyperlipoproteinemia in this condition may be greater than previously recognized. We suggest the need for clarification of both the prevalence and types of hyperlipoproteinemia, as well as the pathophysiology of glucose intolerance and correlation with molecular cytogenetic findings. We also encourage careful monitoring for diabetic complications to further clarify the prevalence and possible accelerated course of microvascular lesions. Am. J. Med. Genet. 71:267-270, 1997. © 1997 Wiley-Liss, Inc.     

Blasts-more than meets the eye: evaluation of post-induction day 21 bone marrow in CBFB rearranged acute leukemia

Induction chemotherapy is often the first therapeutic intervention for acute myeloid leukemia (AML). Evaluation of post induction bone marrow provides critical information for clinical management; in general increased blast countsor increased marrow cellularity is an ominous sign, suggestive of ineffective therapy, and may warrant additional rounds of chemotherapy. However, increased blasts alone are not necessarily predictive of recurrent/persistent disease. Here we report a very unusual observation in a case of AML with a core binding factor beta (CBFB) rearrangement. In this case the day 21 post-induction marrow biopsy showed a high blast count (approximately 20%), however,subsequent fluorescence in-situ hybridization studies were negative for CBFB rearrangement. We compared this finding to post-induction marrows from a series of 6 AML cases with CBFB rearrangements, none of which showed an increased blast count. This case illustrates that increased blast counts, even those comprising 20% of cells, are not de facto evidence of induction failure, and that correlation with ancillary studies such as fluorescence in-situhybridization should be used to distinguish a persistent neoplastic clone, from a brisk marrow recovery.     

Ultrastructural Pathology of Human Immunodeficiency Virus Infection

The electron microscope has been used with great skill in many aspects of the acquired immunodeficiency syndrome. It has played a critical role in classifying the human immunodeficiency virus, in characterizing the morphogenesis and gene products of the virus, and in elucidating the host cell targets and interactions. With the aid of the electron microscope, new opportunistic pathogens are being identified, and particularly difficult diagnoses are being made. Extrapolations from observations made at the ultrastructural level to the light microscopic level have provided criteria for the diagnosis of several infectious agents. As with any powerful scientific tool, observations must be interpreted with great care by scientists experienced in electron microscopy.     

Renal cell carcinomas with t(6;11)(p21;q12) presenting with tubulocystic renal cell carcinoma-like features

In this study, we reported an additional genetically confirmed case of renal cell carcinomas (RCCs) with t(6;11)(p21;q12) showing an unusual histological pattern. Histologically, the tumor was entirely composed of small to intermediate sized tubules and cysts. The tubules and cysts were lined by a single layer of flat, hobnail, cuboidal to columnar epithelial cells. Most cells demonstrated abundant eosinophilic cytoplasm with regular, round or oval nuclei and some inconspicuous nucleoli. All these morphological features are suggestive of tubulocystic carcinoma of the kidney. However, the tumor demonstrated moderately (2+) or strongly (3+) positive staining for TFEB, Cathepsin K, Ksp-cadherin, and vimentin but negative for TFE3, CD10, HMB45, melan A, CKpan, and CK7. Using a recently developed TFEB split FISH assay, the presence of TFEB rearrangement was demonstrated. Our results support the clinical application of a TFEB break-apart FISH assay for diagnosis and confirmation of TFEB RCC and further expand the morphologic spectrum that may be present in these neoplasms, sometimes raising a challenging differential diagnosis with other renal tumors.     

A case report of 46, XX, del (21)(q22) de novo deletion associated with Imerslund-Grasbeck syndrome

We describe a 2-year-old female patient who had megaloblastic anaemia caused by selective vitamin B₁₂ malabsorption (Imerslund-Grasbeck syndrome) and del (21)(q22). To our knowledge, this is the first observation of Imerslund-Grasbeck syndrome associated with del(21)(q22) in the literature.     

Jacobsen distal 11q deletion syndrome with a myelodysplastic change of hemopoietic cells

We describe a male infant with unusual facial appearance, relative pancytopenia, bilateral simian creases, and an accessory nipple. Cytogenetic analysis showed deletion of the long arm of chromosome 11 [46,XY,del(11)(pter→q23.2:)]. Bone-marrow study showed a myelodysplastic change of hemopoietic cells compatible with peripheral blood findings. Pachygyria of the temporal and frontal lobes was demonstrated by magnetic resonance image (MRI) of the brain. We present our findings in order to contribute to the information on 11q23 deletion. Am. J. Med. Genet. 75:341-344, 1998. © 1998 Wiley-Liss, Inc.     

Translocation (1;22)(p36;q11.2) with concurrent del(22)(q11.2) resulted in homozygous deletion of <Emphasis Type="Italic">SNF5/INI1</Emphasis> in a newly established cell line derived from extrarenal rhabdoid tumor

Malignant rhabdoid tumor (MRT) is a highly malignant pediatric cancer, which arises in various sites such as the kidney, brain, and soft tissues. Cytogenetic studies have revealed alterations of 22q11 in MRT. Recently, deletions and mutations of the SNF5/INI1 locus in 22q11.2 have been reported in MRT, suggesting that SNF5/INI1 is a tumor suppressor gene for MRT. Here we report our molecular cytogenetic study for a newly established cell line from extrarenal MRT with t(1;22)(p36;q11.2). Consequently, the reciprocal translocation was associated with the interstitial deletion of a small segment including SNF5/INI1, and another, chromosome 22, showed terminal deletion, the breakpoint of which was located 70–80 kb centromeric to SNF5/INI1, resulting in homozygous deletion of SNF5/INI1 in this cell line.