Interstitial Deletion Of Long Arm Research Articles

A novel deletion in 2q24.1q24.2 in a girl with mental retardation and generalized hypotonia: a case report

BackgroundChromosomal imbalances, recognized as the major cause of mental retardation, are often due to submicroscopic deletions or duplications not evidenced by conventional cytogenetic methods. To date, interstitial deletion of long arm of chromosome 2 have been reported for more than 100 cases, although studies reporting small interstitial deletions involving the 2q24.1q24.2 region are rare. With the widespread clinical use of comparative genomic hybridization chromosomal microarray technology, several cryptic chromosome imbalances have outlined new genotype-phenotype correlations and isolated a number of distinctive clinical conditions.Resultshere we report on a girl with mental retardation and generalized hypotonia. A genome-wide screen for copy number variations (CNVs) using single nucleotide polymorphisms (SNPs) array revealed a 7.5 Mb interstitial deletion of chromosome region 2q24.1q24.2 encompassing 59 genes, which was absent in parents. The gene content analysis of the deleted region and review of the literature revealed the presence of some genes that may be indicated as good candidate in generating the main clinical features of the patient.Discussionthe present case represents a further patient described in the literature with an interstitial deletion of chromosome 2q24.1q24.2. Our patient shares some clinical features with the previously reported patients carriers of overlapping 2q24 deletion. Although more cases are needed to delineate the full-blown phenotype of 2q24.1q24.2 deletion syndrome, published data and present observation suggest that hemizygosity of this region results in a clinically recognizable phenotype. Considering these clinical and cytogenetic similarities, we suggest the existence of an emerging syndrome associated to 2q24.1q24.2 region.

Further delineation of 9q22 deletion syndrome associated with basal cell nevus (Gorlin) syndrome: Report of two cases and review of the literature

Basal cell nevus syndrome (BCNS; Gorlin syndrome) is an autosomal dominant disorder, characterized by a predisposition to neoplasms and developmental abnormalities. BCNS is caused by mutations in the human homolog of the Drosophila patched gene-1, PTCH1, which is mapped on chromosome 9q22.3. Nonsense, frameshift, in-frame deletions, splice-site, and missense mutations have been found in the syndrome. Haploinsufficiency of PTCH1, which is caused by interstitial deletion of 9q22.3, is also responsible for the syndrome. To date, 19 cases with interstitial deletion of long arm of chromosome 9 involving the region of q22 have been reported. We describe two unrelated patients with some typical features of BCNS associated with deletion of 9q21.33-q31.1 and determined the boundary of the deletion by fluorescence in situ hybridization (FISH) with bacterial artificial chromosome (BAC) clones. The results showed that the size of deletions is between 15.33 and 16.04 Mb in patient 1 and between 18.08 and 18.54 Mb in patient 2. Although the size and breakpoints were different from those of previously reported cases, the clinical features are common to patients with 9q22 deletion associated with BCNS. Delineation of the 9q22 deletions and further consideration of the genes responsible for the characteristic manifestations may provide insight into this newly recognized deletion syndrome.

Patient with novel interstitial deletion of chromosome 3q13.1q13.3 and agenesis of the corpus callosum

Interstitial deletions of the proximal long arm of chromosome 3 are rare. Only eight previously reported patients have deletions involving the proximal segment of 3q. Of these patients, three had agenesis of the corpus callosum and one had holoprosencephaly. We report here a patient with a small unique interstitial deletion of the long arm of chromosome 3 spanning 3q13.1q13.3. This patient has agenesis of the corpus callosum, global developmental delay, and distinctive facial features of a small nose, anteverted nares, and broad nasal root. Our patient provides further evidence that a gene involved in corpus callosum development or neuronal migration may reside in this region.

A neuropathological study of a case of the prader-willi syndrome with an interstitial deletion of the proximal long arm of chromosome 15

An autopsy case, a 6-month-old girl, with an interstitial deletion of the long arm of chromosome 15;del(15)(q11.1q12) was reported. Muscle hypotonia, poor sucking and intermittent ocular deviation were noticed soon after birth. She also exhibited external features peculiar to the Prader-Willi syndrome (PWS). The muscle hypotonia persisted and head control was not achieved. She died at the age of 6 months due to bronchopneumonia. G-banding analysis of prometaphase chromosomes revealed a deletion of chromosome 15. Bronchopneumonia of the lungs and fatty metamorphosis of the liver were found. Neuropathological anomalies recognized were; disturbed undulating structures, resembling cortical micropolygyria and pachygyria, in the dentate nucleus and the inferior olivary nucleus, grumose degeneration of the nerve cells in the dentate nucleus, and heterotopia of middle-sized neurons in the cerebellar white matter. No abnormalities were observed in the hypothalamus-pituitary system. In some autopsy cases of PWS, cerebellar lesions have been reported. These might be related to the muscle hypotonia in PWS.

Interstitial Deletion of Long Arm of Chromosome 2(q3 lq33)

We describe the case of a 4-month-old girl with interstitial deletion of the long arm of chromosome 2(46,XX,del(2) (q31q33]. Clinical features included intrauterine growth retardation, psychomotor delay, antimongoloid slanting of the palpebral fissures, hypertelorism, low set ears, cleft palate, micrognathia, luxatio coxae and pes varus. It is suggested that the gene for soluble isocitrate dehydrogenase (IDH1) is located on 2q33.3. The activity of serum IDH1 was in the normal range in this patient.