Interstitial deletion of chromosome 1 del (1) (q32 q42): case report and review of the literature

We describe the case of a female infant with multiple congenital anomalies who was found to have a de novo distal intestinal del (1) (q32 q42). The clinical features of other reports of similar deletions are briefly reviewed. No characteristic phenotype seems to be as yet definable due to the limited number of cases published.     

Deficiency of distal 8p —: report of two cases and review of the literature

A terminal deletion in the short arm of chromosome 8 was found in a 2.5-year-old boy: 46,XY,del(8) (p22.0) and in a 1-year-old girl: 46,XX,del(8) (p23.1) with dysmorphic craniofacial features and developmental retardation. Erythrocyte GSR activities of the boy and of his parents were within normal limits. Vitamin K dependent coagulation factors in the girl and her parents gave normal results. Clinical findings were compared with previously reported cases and suggested a recognizable syndrome.     

Interstitial deletion of 10q: Clinical features and literature review

We report on a patient with interstitial deletion of 10q and compare her to 8 previously described patients, 2 of whom have chromosomal breakpoints similar to our patient. Minor anomalies including broad forehead, hypertelorism, strabismus, prominent philtrum, and “dysplastic” pinnae are present in our patient. Psychomotor retardation and hypotonia are universal findings in 10q interstitial deletion. Growth retardation, not present in our patient, is seen in some. These clinical findings are sufficiently distinct to suggest early chromosome studies. © 1992 Wiley-Liss, Inc.     

Mosaic tetrasomy 8p in two patients: Clinical data and review of the literature

We report on 2 girls with mosaic tetrasomy 8p. Patient 1 showed the extra iso 8p chromosome in 20% of cultured lymphocytes and 18% of cultured fibroblasts [46,XX/47,XX, + i(8p)]. She presented with growth retardation, mild facial alterations, and motor developmental delay. Patient 2 presented with developmental delay, hypotonia, and slight facial alterations; she had the extra iso 8p chromosome in 94% of cultured peripheral lymphocytes. The patients are compared to the 6 previously reported cases. In our experience, the presently reported patients clinically resemble children with inv dup(8)(p21-p22) and patients with mosaic trisomy 8. © 1994 Wiley-Liss, Inc.     

Deficiency of chromosome 8p21.1→8pter: Case report and review of the literature

The clinical manifestations and cytogenetic changes of a patient with 46,XY,del(8)(p21.1) are compared with those of nine other patients with a similar deficiency of chromosome 8. Patients with this chromosome anomaly have a syndrome of postnatal growth retardation, microcephaly, mental retardation, epicanthal folds, posteriorly angulated and malformed ears, short neck, relatively increased internipple distance, and congenital heart defect. A short and broad nose, a wide and flat nasal bridge, and a small jaw are observed in young patients but tend to become less apparent with increasing age. In most instances, the syndrome has been associated with a de novo chromosome abnormality. Levels of glutathione reductase in our patient were normal—a finding consistent with localization of the gene coding for this enzyme to the proximal part of band 8p21.1 if gene dosage studies are reliable.     

Mosaic "tetrasomy" 8p: case report and review of the literature

A male infant presenting with multiple anomalies including a midline cleft palate, anasarca, hepatomegaly, pulmonary edema, agenesis of the corpus callosum, and complex congenital cardiac anomalies was found to have mosaicism for an additional chromosome that appeared (following GTG-banding and FISH) to be a monocentric isochromosome of the short arm of chromosome 8 (46,XY/47,XY,+i(8p)). Nine other cases of mosaicism for an additional i(8p) were reviewed. Considerable phenotypic variation was noted. Consistent features were identified including agenesis of the corpus callosum, cardiac malformations, and minor facial dysmorphology. The phenotype of these patients partially overlaps those of trisomy 8 and trisomy 8p. By studying additional individuals with this condition, mosaic tetrasomy 8p may emerge as a recognizable clinical phenotype.     

Interstitial deletion of chromosome 7: A case report and review of the literature

A de novo deletion 7q11 leads to q21.2 was identified in a newborn with genital and other minor clinical abnormalities and some degree of psychomotor retardation. A review of the literature revealed a number of cases of deletion 7q, which can be categorized into three groups according to their breakpoints. Attempts to correlate phenotype with genotype in these cases have been only moderately successful, and as yet only deletion 7q32 leads to qter can be associated with a definite clinical syndrome, although a tentative syndrome may be postulated in association with deletion of region 7q22 leads to 7q31.     

Structural abnormalities of chromosome 8 and fetoplacental discrepancy: A second case report and review of fetal phenotype of 8p inverted duplication deletion syndrome

We described a new second case of fetoplacental discrepancy involving first trimester prenatal detection of mosaic isochromosome i (8) (q10). A 32-year-old woman underwent chorionic villous sampling because of increased fetal nuchal translucency. Analysis of direct chromosome preparations was performed by R-banding and FISH using subtelomeric, centromeric and whole chromosome painting probes for chromosome 8 showing the presence of an isochromosome 8q with a complex, female mosaic karyotype: mos 46,XX,i (8) (q10)[13]/46,XX,del (8) (p23)[10]. Cytogenetic analysis of cultured CVS showed an interstitial duplication with concomitant terminal deletion of the short arm of chromosome 8: 46,XX,der (8)del (8) (p23)dup (8) (p?)[18]. Array-CGH analysis from cultured trophoblasts and fetal tissues revealed a 6.69 Mb terminal deletion in 8p23.3p23.1 associated with a 31.49 Mb duplication in 8p23.1p11.1. FISH analysis confirmed the 8p inverted duplication deletion syndrome. Moreover, polymorphic DNA marker analysis demonstrated that the derivative chromosome 8 was of maternal origin. FISH analysis of cultured peripheral blood lymphocytes showed that the mother also carried a cryptic paracentric inversion inv (8) (p23). Our report contributes to expand the fetal phenotype of 8p inverted duplication deletion syndrome and also provides further insight into the underlying mechanism of this rare genomic disorder.     

1p36 deletion syndrome: Review and mapping with further characterization of the phenotype,a new cohort of 86 patients

Chromosome 1p36 deletion syndrome (1p36DS) is one of the most common terminal deletion syndromes (incidence between 1/5000 and 1/10,000 live births in the American population), due to a heterozygous deletion of part of the short arm of chromosome 1. The 1p36DS is characterized by typical craniofacial features, developmental delay/intellectual disability, hypotonia, epilepsy, cardiomyopathy/congenital heart defect, brain abnormalities, hearing loss, eyes/vision problem, and short stature. The aim of our study was to (1) evaluate the incidence of the 1p36DS in the French population compared to 22q11.2 deletion syndrome and trisomy 21; (2) review the postnatal phenotype related to microarray data, compared to previously publish prenatal data. Thanks to a collaboration with the ACLF (Association des Cytogénéticiens de Langue Française), we have collected data of 86 patients constituting, to the best of our knowledge, the second-largest cohort of 1p36DS patients in the literature. We estimated an average of at least 10 cases per year in France. 1p36DS seems to be much less frequent than 22q11.2 deletion syndrome and trisomy 21. Patients presented mainly dysmorphism, microcephaly, developmental delay/intellectual disability, hypotonia, epilepsy, brain malformations, behavioral disorders, cardiomyopathy, or cardiovascular malformations and, pre and/or postnatal growth retardation. Cardiac abnormalities, brain malformations, and epilepsy were more frequent in distal deletions, whereas microcephaly was more common in proximal deletions. Mapping and genotype–phenotype correlation allowed us to identify four critical regions responsible for intellectual disability. This study highlights some phenotypic variability, according to the deletion position, and helps to refine the phenotype of 1p36DS, allowing improved management and follow-up of patients.     

Inverted duplication of 8p: Ten new patients and review of the literature

We evaluated 10 patients with an inverted tandem duplication of 8p. Inverted duplications of chromosome 8 have been reported infrequently, and no syndrome has been previously identified. All 8 patients on whom birth histories were available were hypotonic at birth, and had feeding difficulties in the neonatal period. All patients have significant developmental delay. Manifestaions present in 5 or more patients were prominent forehead, high arched palate, large mouth with a thin upper lip, malformed and/or apparently lowset ears, broad nasal bridge, dental and skeletal abnormalities, and joint laxity or hyperextensibility. Variation in the phenotype may, in part, be explained by the different breakpoints. Recurrence risks of de novo rearrangements are probably very low, but for the recombinants the risk may be significant. The duplication appeared to be de novo in 6 patients (both parental karyotypes were normal); maternal karyotypes were normal in 2 patients, and both parrents of 1 patient were not available. One propositus had a monocentric recombinant of a paracentric inv(8) (p12p23.3) carried by the mother, and is one of only 6 known cases of duplication associated with a balanced paracentric inversion in a parent. The carrier parent was the mother in 5 of those 6 cases. Each case involved a different chromosome, and each probably was created by an unusual meiotic recombination event. Inverted duplication 8p is one of the most common duplications observed in our laboratories, and ranks in frequency with the classical deletions, such as Wolf-Hirschhorn and cri-du-chat syndromes and duplication or secondary trisomy 15ql. Since 1/7 cases with complete parental karyotypes was associated with a familial rearrangement, parental karyotype studies should be considered in all cases of tandem duplication. © 1993 Wiley-Liss, Inc.     

Deletion of the long arm of chromosome 6: two new patients and literature review

Two children with a partial monosomy 6q are reported: a girl with an interstitial deletion [46, XX, del(6)(q16.2q23.1)], and a boy with a terminal deletion [46, XY, del(6)(q25.1)]. Both children presented with developmental delay, facial dysmorphism and a cardiac defect. The patients have been studied using G banding and cosmid probes specific for the long arm of chromosome 6. Clinical data are compared with patients reported in the literature.     

Interstitial deletion of the long arm of chromosome 11: Report of a case and review of the literature

Summary A 12-month-old female infant with developmental delay, growth retardation, and dysmorphic features including dolichocephaly, telecanthus, ptosis, flat nasal bridge, anteverted nares, high-arched palate, carp-shaped mouth, micro-retrognathia, and low-set and posteriorly rotated ears was found to have an interstitial deletion of chromosome 11 involving bands q14–q22. Immunoblot analysis of her fibroblasts revealed a normal amount of mitochondrial acetoacetyl-coenzyme A thiolase, of which gene locus has been assigned to chromosome 11q22.3–q23.1. This result suggested that the region around the boundary of 11q22.3–q23.1 was intact in this patient.     

Monosomy 18q 12.1→21.1: A recognizable aneuploidy syndrome? Report of a patient and review of the literature

This report of a patient with an interstitial deletion 18q and review of previously described cases suggest a clinically recognizable syndrome. The phenotype appears to result from a microdeletion of part of 18q12.2 or q12.3, or a deletion of parts of both bands. © 1992 Wiley-Liss, Inc.     

Monosomy 21q: two cases of del(21q) and review of the literature

We report on two cases of partial monosomy 21 and review cases with a partial or an apparently full monosomy 21. In situ hybridization and/or molecular studies appear to be necessary tools to study imbalance in such a small chromosome and to perform further genotype-phenotype correlations. The segregation mode in cases with a translocation is adjacent 1, adjacent 2, and 3:1 in about 1/4, 1/4, and 1/2 of the cases, respectively.     

2q24-q31 deletion: report of a case and review of the literature

We report a patient with a de novo interstitial deletion of the long arm of chromosome 2 involving bands 2q24.3-q31.1. The patient shows postnatal growth retardation, microcephaly, ptosis, down-slanting palpebral fissures, long eyelashes and micrognathia. Halluces are long, broad and medially deviated, while the other toes are laterally deviated and remarkably short with hypoplastic phalanges. She also showed developmental delay, seizures, lack of eye contact, stereotypic and repetitive hand movements and sleep disturbances with breath holding. Prenatal and three independent postnatal karyotypes were normal. Array-CGH analysis allowed us to identify and characterize a "de novo" 2q interstitial deletion of about 10.4Mb, involving segment between cytogenetic bands 2q24.3 and 2q31.1. The deletion was confirmed by quantitative PCR. About 30 children with 2q interstitial deletion have been reported. The deletion described here is overlapping with 15 of these cases. We have attempted to compare the clinical features of our patient with 15 overlapping cases. The emerging phenotypes include low birth weight, postnatal growth retardation, mental retardation and developmental delay, microcephaly, and peculiar facial dysmorphisms. Peculiar long and broad halluces with an increased distance between the first and the second toe are ("sandal gap" sign) present in most of the described patients. The gene content analysis of the deleted region revealed the presence of some genes that may be indicated as good candidates in generating both neurological and dysmorphic phenotype in the patient. In particular, a cluster of SCNA genes is located within the deleted region and it is known that loss of function mutations in SCNA1 gene cause a severe form of epilepsy.     

Interstitial deletion 8p21.3 → p23.1 in a 6-year-old girl

We present a 6-year-old mentally retarded girl. Chromosome analysis showed an interstitial deletion of chromosome 8; 46,XX,del(8) (pter → p23.1::p21.3 → qter). The proposita had normal activities of glutathione synthetase reductase (GSR) and factor VII. Parental chromosomes were normal.