Direct duplication of 8p21.3→p23.1: A cytogenetic anomaly associated with developmental delay without consistent clinical features

We report six cases in two families and a sporadic case with a direct duplication of region 8p21.3→23.1. In one family, the duplication started in the mother and was transmitted to one son and one daughter. In the second family, the father was mosaic for the anomaly that was transmitted to his two daughters. The cytogenetic anomaly was initially described as an 8p+ with banding analysis and then delineated with fluorescence in situ hybridization (FISH) using whole‐chromosome 8 painting, 8p specific painting, and 8p or 8p/8q subtelomeric probes. Deletion was not detected in the subtelomeric region of the abnormal chromosome 8 examined in one family and in the sporadic case. The phenotypic picture varies from normal to moderate mental retardation in the affected individuals. No consistent minor anomalies or congenital defects were observed among these cases. After comparing the chromosome region involved in our cases with those in others having direct or inverted duplications of 8p, it is thought that the segment 8p21.1→21.3 might be the critical region for an 8p duplication syndrome. The parental origin of the duplication does not seem to impact its clinical significance. © 2001 Wiley‐Liss, Inc.     

Familial interstitial deletion 11(p11.12p12) associated with parietal foramina,brachymicrocephaly, and mental retardation

Parietal foramina may be an isolated autosomal dominant trait or found in syndromes. We report on two related individuals who have multiple anomalies with parietal formaina and the deletion of 11(p11.12p12) due to the inheritance of a derivative chromosome 11 from an insertional translocation dir ins(13;11)(q14.1;p11.12p12). Results of initial chromosome analyses on the proposita and her maternal halfuncle were reported as normal. However, the clinical manifestations and family history suggested a chromosomal cause and cytogenetic studies were performed on the proposita's mother. A derivative chromosome 13 was initially identified and further evaluation documented a derivative 11 as the reciprocal product. This family illustrates the importance of performing chromosome studies on the normal intervening relatives in families with multiple affected individuals with mental retardation and minor anomalies as one of the two reciprocal products may be more easily detectable in a balanced carrier. Additionally, the finding of del(11)(p11.12p12) may provide a map location for a syndrome which includes parietal foramina. © 1993 Wiley-Liss, Inc.     

Interstitial deletion of 8q21→22 associated with minor anomalies,congenital heart defect,and Dandy-Walker variant

We describe an infant with a deletion of 8q21→22 who had distinct clinical manifestations including minor facial anomalies, a congenital heart defect, a Dandy-Walker variant, and mild to moderate developmental delay. Her facial characteristics included small, wide-spaced eyes, asymmetric bilateral epicanthal folds, a broad nasal bridge, a “carp-shaped” mouth, micrognathia, and prominent, apparently low-set ears. Three other reports describe children with larger proximal deletions of 8q that include 8q21 and q22. These four children all have similar facial appearance. Of the others reported, one had a congenital heart defect and one had craniosynostosis. This case, in addition to the previously noted three cases, helps in delineating a recognizable syndrome. © 1995 Wiley-Liss, Inc.     

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.     

Del(12)(p11.21p12.2) associated with an asphyxiating thoracic dystrophy or chondroectodermal dysplasia-like syndrome

We describe a 5-year-old Japanese boy who has some radiographic findings characteristic of asphyxiating thoracic dystrophy (ATD)-chondroectodermal dysplasia with a de novo chromosome abnormality. He also has mild mental retardation, short stature, hypoplastic hair and skin, oligodontia, small thoracic cage, hypoplastic pelvis and cone-shaped epiphyses of hands. On cytogenetic studies he was found to have a de novo del(12)(p11.21p12.2). These results suggest that the locus of the gene associated with ATD-chondroectodermal dysplasia may be situated at 12p11.21p12.2. © 1995 Wiley-Liss, Inc.     

A familial MCA/MR syndrome due to translocation t(10;16)(q26;p13.1): Report of six cases

A minute familial translocation t(10;16) (q26;p13.1) was detected in a family with 6 affected children in 2 generations and 9 carriers in 3 generations. This apparently unique translocation is associated with a deleterious syndrome which includes fetal hydrops, ascites, complex congenital heart defect, psychomotor retardation, failure to thrive, hypotonia, narrow palpebral fissures, abnormally modeled, apparently low-set ears, cleft palate, thumb abnormalities, hypogenitalism, inguinal hernia, and sparse hair. All children of known or presumed carriers have been either balanced or unbalanced carriers of this translocation.     

Duplication of chromosome region (16)(p11.2 → p12.1) in a mother and daughter with mild mental retardation

We report a 40‐year‐old female with mild mental retardation and behavior problems and her 6‐year‐old daughter. Chromosome analysis showed that both patients had a proximal duplication in the short arm of chromosome 16. The aberration was characterized further with band‐specific probes, resulting in a 46,XX,dir dup(16)(pter → p11.2::p12.1 → qter) karyotype. The clinical and cytogenetical findings are compared to other patients with partial trisomy 16p reported in the literature. © 2002 Wiley‐Liss, Inc.     

Phenotype associated with ring 10 chromosome: Report of patient and review of literature

A 15-month-old infant's peripheral blood chromosome analysis showed the following defects: 46,XY,r(10)(p15.3q26.1) in 84 cells, 45,XY,?r(10) in 13 cells, and 47,XY,r(10),+r(10) in one cell. Clinical abnormalities included growth retardation, microcephaly, prominent nasal bridge, macular hypoplasia, persistent pulmonary hypertension, and posterior urethral valves with hydronephrosis. Comparison of the phenotype of five other patients with a ring chromosome 10 with the present case showed the following common manifestations: growth retardation, microcephaly, undescended testes, hydronephrosis, and, in males, posterior urethral valves. To date, this last anomaly has not been seen in patients with either a del(10p) or a del(10q) abnormality.     

Duplication of (2)(q11.1‐q13.2) in a boy with mental retardation and cleft lip and palate: Another clefting gene locus on proximal 2q?

A 4‐year‐old boy with left cleft lip and cleft palate, multiple minor anomalies and developmental delay revealed an abnormal chromosome 2 with enlarged proximal long arm, de novo, in his karyotype. Fluorescence in situ hybridization with a chromosome 2 library and band‐specific YACs confined the duplicated segment to 2q11.1‐q13.2 and indicated a direct tandem duplication due to unbalanced crossover between chromatids. © 2002 Wiley‐Liss, Inc.     

Characterization of a t(5;8)(q31;q21) translocation in a patient with mental retardation and congenital heart disease: implications for involvement of RUNX1T1 in human brain and heart development

The chromosome break points of the t(8;21)(q21.3;q22.12) translocation associated with acute myeloid leukemia disrupt the RUNX1 gene (also known as AML1) and the RUNX1T1 gene (also known as CBFA2T3, MTG8 and ETO) and generate a RUNX1–RUNX1T1 fusion protein. Molecular characterization of the translocation break points in a t(5;8)(q32;q21.3) patient with mild-to-moderate mental retardation and congenital heart disease revealed that one of the break points was within the RUNX1T1 gene. Analysis of RUNX1T1 expression in human embryonic and fetal tissues suggests a role of RUNX1T1 in brain and heart development and support the notion that disruption of the RUNX1T1 gene is associated with the patient''s phenotype.