Moderate mental retardation and nonspecific dysmorphic syndrome associated with ring chromosome 9

Summary A ring chromosome 9 is reported in a 12-year-old, moderately mentally retarded boy. As in other ring chromosome 9 patients, the clinical stigmata are nonspecific and their expressivity is mild. The finding of two normal cells of a total of 121 cells examined favors the hypothesis of a postzygotic, mitotic origin of the ring chromosome formation.     

Partial deletion of the long arm of chromosome 13 (q32q33.2) associated with mental retardation, choanal atresia and fish mouth

13q deletion syndrome is characterized by mental and motor retardation, craniofacial dysmorphic facial appearance and various congenital malformations. In this article, we present a new case with 13q deletion syndrome phenotypically characterized by fish mouth, choanal atresia and severe mental and motor retardation. In order to determine the certain localization of deleted region high resolution multicolor-banding technique was performed and the karyotype determined as 46,XX,del(13)(q32q33.2). To come in future to a genotype-phenotype correlation, it is very important to delineate the deleted region in such cases in detail by cytogenetic/ molecular cytogenetic methods.     

Moderate mental retardation and mild dysmorphic syndrome in proximal 7q interstitial deletion

In this report we describe a proximal 7q interstitial deletion in a 3-years-old moderately mentally retarded girl with mild dysmorphic features but absence of severe malformations.     

Langer-Giedion syndrome and deletion of the long arm of chromosome 8

Summary Reexamination of a previously reported patient with 8q interstitial deletion reveals the development of a tricho-rhinophalangeal syndrome type II (Langer-Giedion syndrome) with multiple exostoses at the age of 4 years. Together with the two previous reports on 8q deletion and TRP II syndrome the present observation strongly supports the causal relationship between TRP II syndrome and 8q deletion.     

Langer-Giedion syndrome and deletion in the long arm of chromosome 8

Del(8) (q24.11-q24.13) were detected in 3 patients with typical Langer-Giedion syndrome (LGS) and studied by high-resolution methods. Analysis of the literature strongly suggests the chromosomal ethiology of the LGS, because in all patients examined in detail a deletion of the segment 8(q24.11-q24.13) was revealed, which is critical for the LGS. Interrelationships between the LGS and two monogenic conditions-tricho-rhino-phalangeal syndrome type I and multiple exostoses are discussed. The possible role of c-myc oncogene in exostoses' (including those in LGS) origin is anticipated.     

Dissection of an inverted X(p21.3q27.1) chromosome associated with mental retardation

In a 6 year old boy referred for mental retardation, fragile X syndrome was ruled out by cytogenetic and molecular analyses. Cytogenetic investigations revealed an inverted X chromosome (p21.3q27.1). A similar chromosomal rearrangement was detected in his mildly mentally retarded mother. Fluorescence in situ hybridization (FISH), using a panel of ordered YAC clones, allowed the identification of YACs spanning both the Xp21.3 and Xq27.1 breakpoints, where many non-specific mental retardation loci have been reported so far. Further investigations by FISH showed that the IL1RAPL1 gene at Xp21.3 was disrupted by the X chromosome inversion and therefore its inactivation may be related to the mental retardation observed in our patients.     

Autosomal dominant piebaldism and mental retardation syndrome associated with a t(1;2) (p22.1;q36)

A syndrome of piebaldism and mild to moderate mental retardation was present in 3 sibs and their father. Besides, the disorder was segregating concordantly with a t(1;2) (p22.1;q36). It is concluded that the syndrome is due, either by gene breakage or dysfunction, to the translocation.     

Terminal deletion of the long arm of chromosome 1 in a malformed newborn

Summary Microcephaly and craniofacial dysmorphia, cleft palate, cardiac malformation, and hypospadias are observed in a child with 46,XY,del (1)(q42).     

Inverted distal duplication of the long arm of chromosome 8: borderline intelligence and discrete dysmorphic syndrome.

In this report, we describe an 11-years-old girl with inverted duplication in the distal part of the long arm of chromosome 8 (inv dup(8)(q24.11----q24.3). The most remarkable finding is her borderline intelligence and her nearly normal phenotype.     

A syndrome of severe mental retardation, spasticity, and tapetoretinal degeneration linked to chromosome 15q24.

Nine affected individuals are described from a large extended Pakistani family manifesting a syndrome characterized by a triad of varying degrees of spasticity, severe mental retardation, and visual impairment resulting from tapetoretinal degeneration. In all cases, the parents were at least first cousins, since there was complex consanguinity within the pedigree. The clinical features differ from previously reported syndromes involving pigmentary retinal degeneration and appear to represent a new recessively inherited neurodegenerative condition. Linkage to a 4-5 cM-region between markers D15S211 and D15S152 on 15q24 has been established by autozygosity mapping.     

Distal monosomy of the long arm of chromosome 6 (6q25----6qter) inherited by maternal translocation t(6q;17q)

Two half-sisters with distal monosomy of the long arm of chromosome 6 (q25----qter) inherited by maternal translocation t(6q;17q) were investigated. The clinical manifestations of these patients are compared with eight cases reported in the literature for further characterization of the 6q-syndrome. The cytogenetic diagnosis of alterations involving small chromosome fragments and the different origins of this type of deletion are also discussed.     

Partial deletion of the long arm of chromosome No. 13

Summary A case of partial deletion of chromosome No. 13 identified by G banding as 46,XX,del(13)(q21-qter) is reported in an infant with severe microcephaly, microphthalmos, talipes calcaneovalgus, and a single crease on each of the little fingers. A review of other cases of chromosome No. 13 deletion that were identified by banding is presented and the correlation between clinical features and deletion of specific bands is discussed.     

Hemizygosity of delta-catenin (CTNND2) is associated with severe mental retardation in cri-du-chat syndrome

Delta-catenin is an adherens junction protein involved in cell motility and expressed early in neuronal development. It was discovered as an interactor with presenilin-1. The genomic structure of the human delta-catenin gene (Human Gene Nomenclature Committee-approved symbol CTNND2) was determined and mapped to 5p15.2. A deletion of this chromosomal region has been associated with the cri-du-chat syndrome (CDCS), a segmental aneusomy syndrome of 5p that is associated with an unusual high-pitched cry at birth, facial dysmorphology, poor growth, and severe mental retardation. delta-catenin maps to a specific region in 5p15.2 that has been implicated in the mental retardation phenotype. The breakpoints in patients with 5p terminal deletions were characterized with respect to the severity of mental retardation and the physical location of the delta-catenin gene. A strong correlation was found between the hemizygous loss of delta-catenin and severe mental retardation. These findings and the properties of delta-catenin as a neuronal-specific protein, expressed early in development and involved in cell motility, support its role in the mental retardation of CDCS when present in only one copy.     

Partial maternal heterodisomy of chromosome 17q25 in a case of severe mental retardation

We report a segmental maternal uniparental heterodisomy of chromosome 17 (mat UPD17) in a 3-year-old boy presenting with hyperactivity, major instability, mental retardation and facial dysmorphism. Since conventional and high resolution karyotypes were normal, this patient was tested for cryptic telomeric rearrangements by using the recently developed fluorescent genotyping-based technology. The mat UPD17 segment extended for a small 11-cM region of the distal chromosome 17q. Trisomy 17 in circulating lymphocytes and skin fibroblasts was excluded. Our finding emphasizes the potential use of fluorescent genotyping to detect uniparental disomies and suggests that chromosome 17q25 should contain one or several imprinted genes of particular importance for brain development.     

Terminal deletion of the long arm of chromosome 4. Report of a case of 46, XY, del(4)(q31) and review of 4q- syndrome

Using Q banding technique we recently identified a terminal deletion of the distal segment of the long arm of chromosome 4 in a male infant with multiple long arm of chromosome 4 in a male infant with multiple congenital anomalies. The breakpoint is at 4q31. The infant had hypertelorism, epicanthal folds, depressed nasal bridge, short nasal septum with upturned nose, bilateral open cleft lip and palate, retro- and micrognathia, low set, malformed ear, short neck, distally placed nipples, a sacral dimple, hypospadias, dysplastic nails, overriding toes, simian creases, patterns on interdigital and hypothenar areas, hypoplasia of gallbladder, and cardiac defects consisting of tricuspid atresia, left sided vena cava and anomalous aortic arch. This case is compared to the eight previously reported 4q- cases.