Ikuko Teshima

Speech and language impairment and oromotor dyspraxia due to deletion of 7q31 that involves FOXP2

We report detailed clinical, cytogenetic, and molecular findings in a girl with a deletion of chromosome 7q31‐q32. This child has a severe communication disorder with evidence of oromotor dyspraxia, dysmorphic features, and mild developmental delay. She is unable to cough, sneeze, or laugh spontaneously. Her deletion is on the paternally inherited chromosome and includes the FOXP2 gene, which has recently been associated with speech and language impairment and a similar form of oromotor dyspraxia in at least three other published cases. We hypothesize that our patients communication disorder and oromotor deficiency are due to haploinsufficiency for FOXP2 and that her dysmorphism and developmental delay are a consequence of the absence of the other genes involved in the microdeletion. We propose that this patient, together with others reported in the literature, may define a new contiguous gene deletion syndrome encompassing the 7q31‐FOXP2 region. Cytogenetic and molecular analysis of this region should be considered for other individuals displaying similar characteristics.

Echocardiographic evaluation of the spectrum of cardiac anomalies associated with trisomy 13 and trisomy 18

To investigate the role that cardiac anomalies play in the early death frequently seen in the trisomy 13 and the trisomy 18 syndromes, two-dimensional and Doppler echocardiograms from 31 newborn infants with cytogenetic confirmation of these syndromes seen at one institution over a 4.5 year period (1983 to 1988) were reviewed. The mean age at echocardiography was 1.5 days, and the median age at death was 14 days. Significant cyanosis was present in 58%. Cardiac anomalies that would be considered lethal within the neonatal period were present in only 19% of patients. The most common lesions were atrial septal defect (81%), ventricular septal defect (61%) and patent ductus arteriosus (85%). Most ventricular septal defects and patent ductus arteriosus were large. Valvular dysplasia of one or more valves, graded as mild in most cases, was found in 68%, but was not associated with Doppler evidence of significant regurgitation or stenosis in any subject. Of the four valves, the pulmonary valve, followed by the tricuspid valve, was the most commonly dysplastic. Doppler evidence suggestive of elevated pulmonary artery pressure (low velocity bidirectional flow across the ventricular septal defect and patent ductus arteriosus), although expected, was accompanied by greater than normal mean right ventricular cavity and free wall dimensions in these patients. Thus, although the cardiac anomalies most frequently encountered in trisomy 13 and trisomy 18 are nonlethal, the combined findings of frequent cyanosis and increased right ventricular dimensions suggest that other factors such as pulmonary hypertension, perhaps related to maldevelopment of the pulmonary vasculature, may contribute to early death in some of these infants.

Monozygotic twins with 45,X/46,XY mosaicism discordant for phenotypic sex

We report on two sets of monozygotic twins (MZTs) discordant for phenotypic sex ascertained at birth when the female twin was noted to have signs of the Ullrich-Turner syndrome. Cytogenetic investigations on the female of the first pair showed 45,X/46,XY mosaicism in lymphocytes but fibroblasts grown from two skin biopsies at separate sites and from gonadal tissue showed only 45,X cells. The male showed mosaicism in both blood lymphocytes and skin fibroblasts. In the second family, both twins also showed mosaicism in lymphocytes. The female had a 45,X karyotype in fibroblasts from skin and gonadal tissue, but in contrast to the first family, the male twin had a normal male karyotype in fibroblasts from skin biopsy and from connective tissue adjacent to the vas deferens. Discordant phenotypic sex in monozygotic twins is rare. As in our cases, the nine previously reported sets of MZTs all had mosaicism for sex chromosome abnormalities. A mitotic error leading to the loss of a Y chromosome prior to, accompanying, or following the twinning process would account for the reported combinations of karyotypes.

Primary Ewing's sarcoma of the skull in children. Utility of molecular diagnostics, surgery and adjuvant therapies.

Ewing’s sarcoma (ES) of the skull is rare. Herein, we present 2 cases of ES that involved the cranium in young children. In one case, the lesion originated in the petrous temporal bone; in the other, the frontal bone. Both children were acutely compromised neurologically by signs and symptoms of raised intracranial pressure. In both cases, radiographs revealed massive tumors affecting the skull. Neurosurgical resection of the tumor was undertaken in both instances, and the diagnosis of ES was confirmed by immunohistochemistry, cytogenetic analysis (translocation 11;22), spectral karyotyping and RT-PCR (demonstration of a EWS/FLI1 fusion transcript). Following aggressive surgical resection, both children received intensive chemotherapy. No child has received radiation therapy. One child is alive and well 8 years after diagnosis without any evidence of residual disease. The other is currently undergoing chemotherapy for her tumor. The principles involved in the management of children with cranial-based ES are discussed. These 2 cases serve to illustrate the fact that even children with massive ES tumors of the cranium may be salvaged with aggressive combination therapy.

Ring chromosome 22 and autism: Report and review

Ring chromosome 22 has been described in over 50 cases. A characteristic phenotype has not been fully delineated; however, long face, thick eyebrows, 2-3 toe syndactyly, mental retardation, adequate somatic growth and the absence of major malformations are noted in many cases. An 11-year-old boy with ring chromosome 22 and 46,XY,r(22)(p11.31-q13.31 approximately q13.33) karyotype presented with global developmental delay, autistic disorder, and dolichocephaly, apparently low-set and large ears, midface hypoplasia, and 2-3 toe syndactyly. This is the second report of a ring chromosome 22 with autistic disorder. There appears to be an association between abnormalities of chromosome 22, including r(22), and autistic disorder; however, this occurrence may be a result of the association of autistic disorder with mental retardation rather than specifically due to r(22). The physical findings in this case also suggest that ring chromosome 22 causes a subtle but distinct phenotype which has previously been proposed.

Tissue-specific methylation differences and cognitive function in fragile X premutation females.

Tissue-specific variation in (CGG)n repeat size and methylation status of the FMR1 gene was investigated in 17 female premutation carriers. Minor variation in premutation repeat size among leukocyte, lymphoblast, and fibroblast tissues was noted in some subjects. One subject exhibited a premutation size allele of (CGG)64 in leukocyte and fibroblast tissues by polymerase chain reaction analysis but a normal-size allele of (CGG)46 in lymphoblast cells, suggesting low-level mosaicism in blood and clonality of the lymphoblast cell line. Six subjects exhibited differences in methylation pattern between leukocytes and lymphoblasts but not between leukocytes and fibroblasts, whereas 2 subjects showed large differences in methylation pattern between leukocytes and fibroblasts. Cognitive function was studied in 14 subjects using the Wechsler Adult Intelligence Scale-Revised. Mean Verbal and Performance IQs were well within the average range as was the mean Full Scale IQ; nevertheless, a trend toward lower Performance IQ compared with Verbal IQ was observed. No significant correlation was apparent between Full Scale IQ and (CGG)n repeat size; however, a significant positive correlation was observed between Full Scale IQ and the proportion of the active X carrying the normal FMR1 allele in fibroblasts but not in leukocytes or lymphoblasts.

Association of the t(12;22)(q13;q12) EWS/ATF1 rearrangement with polyphenotypic round cell sarcoma of bone: a case report.

The t(12;22)(q13;q12) chromosomal rearrangement results in an EWS/ATF1 fusion transcript and is associated with clear cell sarcoma (CCS). CCS is an uncommon tumor arising in tendons and aponeuroses of the extremities and shows evidence of melanocytic differentiation at the light microscopic, immunohistochemical, and/or ultrastructural level. Only 5 cases have been reported to arise in bone, none of which had molecular confirmation of the diagnosis. The current report describes a 7-year-old girl with a primary round cell sarcoma of the left humerus showing polyphenotypic differentiation on immunohistochemical analysis. Antibodies directed at melanocytic antigens were negative, and there was no evidence of melanocytic differentiation by light microscopy or ultrastructural analysis. Cytogenetic analysis revealed rearrangement of the EWS locus within 22q12. RT-PCR and sequence analysis revealed the presence of a fusion transcript bringing together exon 7 of EWS with exon 5 of ATF1, consistent with a type 2 transcript reported in association with CCS. However, given the lack of morphologic features usually present in CCS, a diagnosis of polyphenotypic round cell sarcoma was made. This tumor thus expands the spectrum of neoplasms associated with the t(12;22)(q13;q12) rearrangement.

Deletion 4q21/4q22 syndrome: Two patients with de novo 4q21.3q23 and 4q13.2q23 deletions

We report on 2 patients with de novo proximal interstitial deletions of the long arm of chromosomes 4: in one the deletion resulted in monosomy (4)(q21.3q23), in the other it produced monosomy (4)(q13.2q23). Review of 9 cases of deletions involving the 4q21/4q22 region reported previously detected a characteristic phenotype in 8 patients. This phenotype was present in our patients. We conclude that the deletion in the 4q21/4q22 region results in a specific clinical syndrome associated with central nervous system overgrowth that may be a result of anomalous imprinting in the 4q21/4q22 region.

Localization and genetic linkage of the human immunoglobulin heavy chain genes and the creatine kinase brain (CKB) gene: identification of a hot spot for recombination.

The immunoglobulin heavy chain (IGH) gene cluster and the gene coding for the brain form of the enzyme creatine kinase (CKB) have previously been localized to chromosome 14, at 14q32.3 and 14q32, respectively. Here we report more precise regional localization of these genes by dosage studies using DNA from a child hemizygous for the region from 14q32.32 to 14qter. CKB and IGH are present in a single dose in the proband. Dosage studies in a second patient with a similar but smaller deletion due to a ring chromosome 14 show that CKB is proximal to the IGH cluster. An EcoRI restriction site polymorphism was found with probes for the CKB gene. Linkage analysis of family data indicates that CKB is closely linked to IGH. Linkage analysis also revealed unusually high recombination (beta = 3.2%) between the C delta and C gamma 3 genes of the IGH constant region, which are only 60 kb apart. This finding, in combination with a previous observation of linkage equilibrium in the region, suggests that the C delta-C gamma 3 region contains a recombination hot spot.

Terminal deletion of the long arm of chromosome 3 [46,XX,del(3)(q27→qter)]

We report on a terminal deletion of the long arm of chromosome 3 [46,XX,del(3)(q27-->qter)] in a female newborn infant who died 45 hours after delivery and had multiple congenital abnormalities including bilateral anophthalmia, congenital heart disease, and abnormal genitalia. The findings are compared to those of four previously reported cases with terminal del (3q).