Holoprosencephaly and sacral agenesis in a fetus with a terminal deletion 7q36-->7qter.

We describe here a fetus with holoprosencephaly and signs of caudal deficiency sequence. Chromosome examination showed a de novo balanced reciprocal translocation (7;22) (q36;q11) with loss of the derivative chromosome 22 in 50% of the cells examined. The present report and available published data indicate that the terminal region of the long arm of chromosome 7 contains genes implicated in the development of the central nervous system and the caudal region.     

Two unrelated cases of single maxillary central incisor with 7q terminal deletion

Two unrelated cases of single maxillary central incisor (SM-CI) with 7q terminal deletion of the same breakpoint at 7q36.1 were described. They had mental retardation, microcephaly, hypotelorism, short stature, and normal levels of plasma growth hormone. One case had bilateral caudal ectopic kidneys, double renal pelves, and dilated ureters. The other had bilateral hydroureteronephrosis. The present cases suggest that 7q terminal deletion is one of the causes of SMCI.     

Del(4)(q33----qter): another case report of a child with mild dysmorphism.

A male child is described with some growth and developmental delay and other minor dysmorphic features. Chromosome analysis showed a de novo deletion of the q33----qter terminal segment of a chromosome 4. There has been published discussion concerning the severity of phenotypic malformations in the seven cases described so far with this particular deletion. We add details of our patient to help to delineate further features of this syndrome.     

Terminal 22q deletion associated with a partial deficiency of arylsulphatase A.

A 7 month old girl with psychomotor retardation, hypotonia, and minor malformations was found to have a terminal deletion of the long arm of chromosome 22, del(22)(q13.31). The partial deficiency of arylsulphatase A (ARSA) and the normal level of NADH diaphorase 1 (DIA1) suggests that the ARSA locus can be regionally assigned to 22q13.31----qter and the DIA1 locus can be excluded from the same segment. This report is the third published case with a terminal 22q deletion.     

Deletion of chromosome region 18q21.1 --> 18q21.3 in a patient without clinical features of the 18q- phenotype

In a 16-month-old boy referred because of developmental delay and asymmetric motor development, chromosome analysis showed an aberrant chromosome 18 in all 25 metaphases examined. The chromosome aberration was initially interpreted either as an interstitial deletion of chromosome region 18q21.1 --> 18q21.3 or an unbalanced translocation involving the distal part of the long arm of chromosome 18. Chromosome microdissection in combination with fluorescence in situ hybridization demonstrated that the aberrant chromosome 18 had an interstitial deletion, the karyotype being: 46,XY,del(18)(q21.1q21.3). At age 27 months, his development was moderately retarded. He showed craniofacial asymmetry but no other anomalies. The clinical and cytogenetic findings are compared with previously reported patients with a terminal or interstitial deletion in the long arm of chromosome 18.     

Jacobsen syndrome: report of a patient with severe eye anomalies, growth hormone deficiency, and hypothyroidism associated with deletion 11 (q23q25) and review of 52 cases.

We have evaluated a patient with Jacobsen syndrome. The patient presented with growth retardation, hypotonia, trigonocephaly, telecanthus, downward slanting palpebral fissures, bilateral inferior colobomas (of the iris, choroid, and retina), hydrocephalus, central nervous system (CNS) abnormalities, and an endocardial cushion defect, features commonly seen in Jacobsen syndrome. Endocrine evaluation showed growth hormone deficiency and central hypothyroidism. Chromosome analysis showed a 46,XX,del(11)(q23q25) de novo karyotype. Cytogenetically, the deletion appeared to include most of bands 11q23 and q24 and a portion of q25. Using chromosome specific paint probe, a combination of chromosome 11 centromere, telomere, and region specific cosmid probes from 11q14.1-14.3, 11q23.3, and 11q24.1, we have localised the deletion breakpoint to q24.1. Phenotype-karyotype correlation of patients with Jacobsen syndrome and specific deletions of chromosome 11q has enabled us to suggest that the critical region for this syndrome lies in close proximity to cytogenetic band 11q24. Although growth retardation is a consistent finding in 11q deletion syndrome, the presence of hypothalamic-pituitary hormone deficiency has not been reported previously.     

A terminal deletion of the long arm of chromosome 4 [46,XX,del(4)(q33)] in an infant with phenotypic features of Williams syndrome.

A female infant with peripheral pulmonary artery stenosis, growth retardation, and developmental delay was noticed to have facial features consistent with a diagnosis of Williams syndrome. Chromosome analysis revealed a deletion of the terminal portion of the long arm of chromosome 4 (4q33----qter). This is the seventh reported case of this chromosome disorder. It is possible that this chromosome region is specific for the Williams syndrome phenotype but it is more likely that the syndrome is heterogeneous. Chromosome analysis should be performed in all suspected cases with particular attention to the long arm of chromosome 4.     

Two new cases of pure 1q terminal deletion presenting with brain malformations

We describe two new cases of pure 1q terminal deletions. BAC FISH analysis precisely defined the size of deletions. The first is a girl with 10.3-Mb deletion showed typical features of 1q43 deletion as well as a simplified gyral pattern, which was rarely found in 1q43 deletion. The other boy also presented with most of 1q43 deletion features but several atypical symptoms were noted including hydrocephalus, adducted thumbs, and flexion restriction of proximal interphalangeal joints in left hand. A concomitant novel missense mutation in L1CAM was identified in addition to 11.5-Mb deletion. Reviewing all the cases of pure 1q terminal deletion in the literature suggests that it is a clinically recognizable syndrome.     

Robin sequence and a deficiency of the left forearm in a girl with a deletion of chromosome 4q33-qter.

We have investigated a patient with the Robin sequence and a unilateral deficiency of the left forearm. She was found to have a terminal deletion of the long arm of chromosome 4, del(4)(q33). The clinical manifestations of this patient differ from those of 7 previously described patients with a deletion of the same segment.     

Delineation of 14q32.3 deletion syndrome.

A patient with a 14q32.3 terminal band deletion and cat cry is reported. Review of four other 14q32.3 deletion cases suggests the possible presence of a recognisable 14q32.3 terminal deletion syndrome, which is characterised by (1) apparently postnatal onset of small head size in comparison to body size, (2) high forehead with lateral hypertrichosis, (3) epicanthic folds, (4) broad nasal bridge, (5) high arched palate, (6) single palmar crease, and (7) mild to moderate developmental delay. Although none of the above seven features in unique to this syndrome, and indeed are quite common in other chromosomal disorders or genetic syndromes, patients with a terminal 14q32.3 deletion do show a recognisable facial gestalt. Interestingly, unlike ring chromosome 14, the 14q32.3 terminal deletion has rarely been reported, possibly because it is harder to detect, and an optimal chromosome preparation is required for its identification.     

Conotruncal anomaly face syndrome is associated with a deletion within chromosome 22q11.

The conotruncal anomaly face syndrome was described in a Japanese publication in 1976 and comprises dysmorphic facial appearance and outflow tract defects of the heart. The authors subsequently noted similarities to Shprintzen syndrome and DiGeorge syndrome. Chromosome analysis in five cases did not show a deletion at high resolution, but fluorescent in situ hybridisation using probe DO832 showed a deletion within chromosome 22q11 in all cases.     

Wilms tumor incidence in children with 2q terminal deletions: a cohort study

Three individuals with chromosome 2q terminal deletions have been reported in the medical literature to have developed Wilms tumor. By looking at a UK national cohort, we aimed to ascertain the chance of an individual with a 2q terminal deletion developing a Wilms tumor. The objective was to clarify screening recommendations. All individuals over a 40-year period with chromosome 2q terminal deletions were ascertained from the Chromosome Abnormality Database. The names and dates of birth of these individuals were obtained from the Regional Cytogenetic Departments where the original chromosome analyses were performed. These data were collated and compared with the National Registry of Childhood Tumors. One hundred twenty-nine subjects were identified over a 40-year study period. Only a single individual in our national cohort was affected by Wilms tumor. This individual had an add(2)(q35) karyotype. We conclude that the incidence of Wilms tumor in the majority of individuals with a 2q terminal deletion is low, and is below the recommended threshold for surveillance for tumor development.     

Association of Jacobsen syndrome and bipolar affective disorder in a patient with a de novo 11q terminal deletion

We report on a young woman with Jacobsen syndrome (JBS) who was admitted to our psychiatric department because of a bipolar affective disorder (BPAD). Chromosome analysis was performed due to the fact that she had mental retardation, short stature, and subtle facial anomalies. A deletion of the distal long arm of chromosome 11 was found. A detailed mapping of the deletion breakpoint by quantitative real time PCR revealed a true terminal 11q deletion of approximately 8 Mb corresponding to the karyotype 46,XX,del(11)(q24.2). Polymorphic DNA marker analysis showed that the deletion is located on the paternal chromosome. Additionally, laboratory investigations revealed a low platelet count and magnetic resonance imaging of the brain showed white matter T2 hyperintensities in frontotemporal regions, which are unlikely to result from a demyelinating process as indicated by localized proton magnetic resonance spectroscopy. To our knowledge, this is the first report describing a BPAD in a case with JBS.     

Uncommon cytogenetic findings in a case of splenic marginal zone lymphoma with aggressive clinical course

The majority of splenic marginal zone lymphoma (SMZL) patients experience an indolent clinical course; however, some cases transform to a high-grade lymphoma. Cytogenetic analyses have shown that chromosome 7 is the most frequently altered chromosome and, in some cases, 7q deletion has been found as a single aberration, suggesting its association with the development of SMZL. We studied one patient showing clinical features of SMZL with an aggressive course. Immunophenotypic, conventional and molecular cytogenetic techniques were applied to support the diagnosis. The immunophenotype of peripheral blood mononuclear cells showed the presence of 90% B-lymphocytes. Cytogenetic analysis indicated the presence of a stem-line lacking normal chromosomes 7, but showing a der(7) and a ring, and a side-line with additional aberrations: t(2;22), add(8). Fluorescence in situ hybridization analysis revealed a loss of the 7q32 region. Nonclonal rearrangements involving chromosome 7 were also detected. Chromosome 7 rearrangements were studied to investigate their evolution during the development of the pathology. We have shown that in this patient both chromosomes 7 underwent different rearrangements leading to a loss of the 7q32 region and that the ring chromosome originated from chromosome 7 and was associated with a t(7;7) (p22;q31). We conclude that not only the 7q deletion but also the proneness of chromosome 7 to rearrange might have played a role in the progression of this SMZL.     

Terminal deletion of the chromosome 7(q36-qter) in an infant with sacral agenesis and anterior myelomeningocele

We report on a new patient with a 7q terminal deletion. The 18-month-old boy had metal retardation, microcephaly, a distinctive face, bilateral coloboma, café-au-lait spot on the abdomen, and sacral agenesis. The high resolution GTG bands (550-850 bands), currently used in our laboratory, showed a 7q terminal deletion, which was also confirmed with fluorescence in situ hybridization (FISH). The homeobox HLXB9 gene, localized at 7q36 has been demonstrated to be involved in sacral agenesis; in fact patients with 7q terminal deletions frequently have this malformation. We could not perform molecular studies in this patient to confirm the HLXB9 haploinsufficiency, but we postulate that he carried it.     

Short communication: deletion 7q, trisomy 6 and 11 in a case of Merkel-cell carcinoma

Chromosome analysis of a metastatic Merkel-cell carcinoma established as xenografted tumor line in nude mice was performed. The analyzed karyotypes showed a stable cytogenetic feature characterized by trisomy 6 and 11 and a partial deletion of the long arm of chromosome #7 with the breakpoint localized at q31.2.     

Asymmetry and skin pigmentary anomalies in chromosome mosaicism.

We report six persons mosaic for a chromosome anomaly. All were mentally retarded and dysmorphic. Unilateral or asymmetrical features were found in all cases, in one an unusual transverse terminal limb anomaly, and in the others various degrees of hemiatrophy of the left side of the body. Five of the subjects had skin pigmentary anomalies which were distributed in the lines of Blaschko. The abnormal cell lines found were ring chromosome 22, trisomy 22, a large acrocentric marker, a deletion of 18q, a deletion of 8q, and triploidy. In four cases the clinical diagnosis was only confirmed by skin biopsy. In one case low level mosaicism in blood was fortuitously detected because of cytogenetic fragile X screening and confirmed in a skin biopsy. The sixth case was of dynamic mosaicism of a non-mosaic deletion 18q with a chromosome 18 derived marker present in a proportion of cells. Chromosome mosaicisn may cause subtle and asymmetrical clinical features and can require repeated cytogenetic investigations. The diagnosis should be actively sought as it enables accurate genetic counselling to be given.     

Cytogenetic and molecular studies in patients with chronic myeloid leukemia and variant Philadelphia translocations

Out of 105 Philadelphia (Ph) positive chronic myeloid leukemia patients analyzed, six (5.7%) carried a variant Ph translocation, namely t(6;9;9;10;22)(q24;p13;q34;p15;q11); t(9;13;22)(q34;q21;q11);der(2)(2pter----2q31::9q21---- 9q34::22q11----22qter) and der(9)t(2;9) (9pter----9q21::2q31----2qter);t(7;9;22)(q11;q34 ;q11), 14q + ;t(7;9;22)(q35;q34;q11), and t(9;11;22) (q34;q13;q11), respectively. Five of these patients were analyzed with Southern blotting. Three of them showed an atypical molecular pattern; namely, the patient with t(9;13;22) showed no rearrangement in the breakpoint cluster region (bcr), the patient with t(7;9;22)(q35;q34;q11) showed a 3' deletion, and the patient with t(7;9;22), 14q + showed a bcr rearrangement 3' to the exon 4 of the M-BCR. Chromosome in situ hybridization studies demonstrated that in patient one, a two-step translocation occurred: the first step moved the 3' bcr from chromosome 22 to chromosome 9, and the second moved the terminal part of 22q, carrying the c-sis protooncogene, to 10p. Variant Ph translocations appear to be associated with atypical molecular breakpoints.     

Cryptic subtelomeric translocations in the 22q13 deletion syndrome

Cryptic subtelomeric rearrangements are suspected to underlie a substantial portion of terminal chromosomal deletions. We have previously described two children, one with an unbalanced subtelomeric rearrangement resulting in deletion of 22q13→qter and duplication of 1qter, and a second with an apparently simple 22q13→qter deletion. We have examined two additional patients with deletions of 22q13→qter. In one of the new patients presented here, clinical findings were suggestive of the 22q13 deletion syndrome and FISH for 22qter was requested. Chromosome studies suggested an abnormality involving the telomere of one 22q (46,XX,?add(22)(q13.3)). FISH using Oncor D22S39 and Vysis ARSA probes confirmed a terminal deletion. A multi-telomere FISH assay showed a signal from 19qter on the deleted chromosome 22. Results were confirmed with 19qtel and 22qtel specific probes. The patient is therefore trisomic for 19qter and monosomic for 22qter. The patient''s mother was found to have a translocation (19;22)(q13.42;q13.31). We also re-examined chromosomes from two patients previously diagnosed with 22q deletions who were not known to have a rearrangement using the multi-telomere assay. One of these patients was found to have a derivative chromosome 22 (der(22)t(6;22)(p25;q13)). No evidence of rearrangement was detected in the other patient. Thus we have found the 22q13 deletion to be associated with a translocation in three of four patients. This report illustrates the usefulness of examining patients with hypotonia, severe language delay, and mild facial dysmorphism for this syndrome and suggests that most of these deletions may be unbalanced subtelomeric rearrangements.     

Deletion mapping of chromosomes 8, 10, and 16 in human prostatic carcinoma

In an allelotyping study prostatic carcinoma, we found the highest frequency of allelic deletions on chromosomes 8, 10, 16, and 18. In all cases with allelic deletions, at least one of the chromosomes 8, 10, and 16 were involved. A detailed deletion mapping of these chromosomes in 18 cases was carried out with probes that detect restriction fragment length polymorphisms (RFLP) on chromosomes 8 (6 probes), 10 (11 probes), and 16 (9 probes). The highest frequency of allelic deletions were found on 8p (65%), where the minimally deleted region was between the PLAT locus and pter. The long arm of chromosome 16 had allelic deletions in 56% of informative cases, with three different break points, the most distal being located between D16S4 and D16S7. Chromosome 10 exhibited a complex deletion pattern with terminal deletions of the p or the q arm (2 cases each), a deletion pattern that could be interpreted as nonreciprocal translocations of the q arm (2 cases), or allelic losses on all informative loci, suggesting monosomy (2 cases). Our data suggest that tumor suppressor genes involved in the oncogenesis of prostatic carcinoma may be localized between 8 pter and the PLAT locus and that additional/alternative tumor suppressor genes may be localized on chromosome 10 and on the long arm of chromosome 16 distal to the D16S4 locus.