Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Potocki-Shaffer syndrome (PSS) is a contiguous gene deletion syndrome that results from haploinsufficiency of at least two genes within the short arm of chromosome 11[del(11)(p11.2p12)]. The clinical features of PSS can include developmental delay, mental retardation, multiple exostoses, parietal foramina, enlarged anterior fontanel, minor craniofacial anomalies, ophthalmologic anomalies, and genital abnormalities in males. We constructed a natural panel of 11p11.2-p13 deletions using cell lines from 10 affected individuals, fluorescence in situ hybridization (FISH), microsatellite analyses, and array-based comparative genomic hybridization (array CGH). We then compared the deletion sizes and clinical features between affected individuals. The full spectrum of PSS manifests when deletions are at least 2.1 Mb in size, spanning from D11S1393 to D11S1385/D11S1319 (44.6-46.7 Mb from the 11p terminus) and encompassing EXT2, responsible for multiple exostoses, and ALX4, causing parietal foramina. Yet one subject with parietal foramina whose deletion does not include ALX4 indicates that ALX4 in this subject may be rendered functionally haploinsufficient by a position effect. Based on comparative deletion mapping of eight individuals with the full PSS syndrome including mental retardation and two PSS families with no mental retardation, at least one gene related to mental retardation is likely located between D11S554 and D11S1385/D11S1319, 45.6-46.7 Mb from the 11p terminus.
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PMID:Construction of a natural panel of 11p11.2 deletions and further delineation of the critical region involved in Potocki-Shaffer syndrome. 1585 40

Aniridia usually occurs in isolation, but may also occur as part of the WAGR contiguous gene deletion syndrome, which includes Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation. The aniridia and predisposition for Wilms tumor seen in WAGR are caused by haploinsufficiency for PAX 6 and WT1, respectively. We present a female infant with aniridia, bilateral ptosis, bilateral posterior capsular cataracts, nystagmus, left-sided glaucoma, microcephaly, mild unilateral hydronephrosis, poor linear growth, and gross motor delay consistent with a clinical diagnosis of WAGR syndrome. In addition, weight-for-height ratio at 12 months is at the 94th centile, raising the possibility of a diagnosis of WAGRO (WAGR + Obesity). Chromosome analysis revealed a translocation (11;15)(p13;p11.2) which has not been previously associated with a diagnosis of WAGR. Subsequent clinical WAGR fluorescent in situ hybridization (FISH) analysis demonstrated a deletion of 11p13 including PAX6 and WT1. A complete FISH-mapping of the breakpoints on chromosome 11 revealed a 7 Mb deletion within 11p13-11p14. The patient is examined in light of other reported patients with deletions and/or translocations involving the regions between 11p12 --> 11p14 including patients with WAGR + obesity (WAGRO) as well as with other reported patients with aniridia and congenital ptosis.
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PMID:WAGR(O?) syndrome and congenital ptosis caused by an unbalanced t(11;15)(p13;p11.2)dn demonstrating a 7 megabase deletion by FISH. 1664 34

Congenital insensitivity to pain is a rare hereditary neuropathy. We present patients from a large family in Norrbotten, Sweden with a mutation in the nerve growth factor beta gene (NGFbeta). Using a model of recessive inheritance, we identified an 8.3-Mb region on chromosome 1p11.2-p13.2 shared by the affected individuals in the family. Analysis of candidate genes in the disease-critical region revealed a mutation in the coding region of the NGFbeta gene specific for the disease haplotype. All three severely affected individuals were homozygous for the mutation. The disease haplotype was also observed in both unaffected and mildly affected family members, but in heterozygote form. We have identified 43 patients, 3 homozygous and 40 heterozygous. The homozygous patients have a severe congenital form with onset of symptoms at an early age, most often affecting the lower extremities with insidious progressive joint swellings or painless fractures. Fracture healing was normal, but the arthropathy was progressive, resulting in disabling Charcot joints with gross deformity and instability. These patients lacked deep pain perception in bones and joints and had no protective reflexes, leading to gross bone and joint complications. They also had abnormal temperature perception but normal ability to sweat. There was no mental retardation. Clinically, they fit best into the group HSAN type V. Sural nerve biopsies showed a moderate loss of thin myelinated fibers (Adelta-fibers) and a severe reduction of unmyelinated fibers (C-fibers). 14 of the 40 heterozygous adult patients had mild or moderate problems with joint deformities, usually with only slight discomfort. Treatment was conservative with (if needed) different kinds of orthosis and in three cases joint replacement. Nine patients had neuropathy, and nine patients had no symptoms. In congenital disorders like these, it is important to evaluate the age and also the slowly progressive nature, when considering treatment. There is an increased risk of growth disturbances in the very young. The orthopedic operations should therefore be planned from a long-term point of view, but patient education and orthosis are cornerstones in the treatment--to delay the development of neuropathic arthropathy. Arthrodesis, limb lengthening and spinal decompression with fusions are the only elective procedures that seem reasonable. This Norrbottnian disease is also interesting as a model system for the study of pain.
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PMID:Norrbottnian congenital insensitivity to pain. 1676 23

We report clinical findings and molecular cytogenetic analyses for two patients with translocations [t(14;17)(p12;p12) and t(15;17)(p12;p13.2)], in which the chromosome 17 breakpoints map at a large low-copy repeat (LCR) and a breakage-prone TRE-2 (USP6) oncogene, respectively. In family 1, a 6-year-old girl and her 5-year-old brother were diagnosed with mental retardation, short stature, dysmorphic features, and Charcot-Marie-Tooth disease type 1A (CMT1A). G-banding chromosome analysis showed a der(14)t(14;17)(p12;p12) in both siblings, inherited from their father, a carrier of the balanced translocation. Chromosome microarray and FISH analyses revealed that the PMP22 gene was duplicated. The chromosome 17 breakpoint was mapped within an approximately 383 kb LCR17pA that is known to also be the site of several breakpoints of different chromosome aberrations including the evolutionary translocation t(4;19) in Gorilla gorilla. In family two, a patient with developmental delay, subtle dysmorphic features, ventricular enlargement with decreased periventricular white matter, mild findings of bilateral perisylvian polymicrogyria and a very small anterior commissure, a cryptic duplication including the Miller-Dieker syndrome region was identified by chromosome microarray analysis. The chromosome 17 breakpoint was mapped by FISH at the TRE-2 oncogene. Both partner chromosome breakpoints were mapped on the short arm acrocentric heterochromatin within or distal to the rRNA cluster, distal to the region commonly rearranged in Robertsonian translocations. We propose that TRE-2 together with LCR17pA, located approximately 10 Mb apart, also generated the evolutionary gorilla translocation t(4;19). Our results support previous observations that the USP6 oncogene, LCRs, and repetitive DNA sequences play a significant role in the origin of constitutional chromosome aberrations and primate genome evolution.
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PMID:Evidence for involvement of TRE-2 (USP6) oncogene, low-copy repeat and acrocentric heterochromatin in two families with chromosomal translocations. 1679 15

In recent years, subtelomeric rearrangements have been identified as a major cause of multiple congenital anomalies (MCA)/mental retardation (MR) syndromes. Currently, more than 2,500 individuals with MR have been tested and subtelomeric rearrangements were detected in about 6%. Therefore, subtelomeric FISH analysis is indicated as a second tier test after high-resolution G-banding analysis, in subjects with otherwise unexplained developmental delay/MR and/or MCA. We describe a female patient and her maternal aunt, both showing a distinct phenotype, associated with the same complex subtelomeric rearrangement. Subtelomeric FISH testing performed between 1 year 9 months and 20 years after the initial karyotype showed, in both patients, distal trisomy 12p and distal monosomy 10p as follows: 46,XX.ish der(10)t(10;12)(p15.3;p13.31). Parental subtelomeric FISH analysis showed the proposita's mother (sister of Patient 2) and grandmother (mother to Patient 2), to have a balanced 10p:12p translocation. Both girls showed a similar phenotype with pre/postnatal growth retardation, moderate-to-severe developmental delay/MR, very poor/absent speech, hypotonia, lax ligaments, and a distinct pattern of malformation. On examination there were blepharophimosis; bilateral ptosis/epicanthus; broad, depressed nasal bridge with a beaked nose; short philtrum; low-set, posteriorly rotated, overfolded ears; micrognathia; mild webbing of the neck; mild broadening of thumbs; puffy hands/feet; long hallux; and sacral/coccygeal dimples. A slow overall improvement was seen in both patients over time. To our knowledge, a complex subtle rearrangement as the one seen in our patients has not been reported thus far. Our patients show features of partial 10p deletion syndrome rather than those of partial duplication 12p, confirming the general rule that deletions are more phenotypically penetrant than duplications.
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PMID:Subtelomeric analysis detects a familial 10p;12p rearrangement in two relatives with a distinct syndrome. 1716 46

Autosomal recessive inheritance of non-syndromic mental retardation (ARNSMR) may account for approximately 25% of all patients with non-specific mental retardation (NSMR). Although many X-linked genes have been identified as a cause of NSMR, only three autosomal genes are known to cause ARNSMR. We present here a large consanguineous Turkish family with four mentally retarded individuals from different branches of the family. Clinical tests showed cognitive impairment but no neurological, skeletal, and biochemical involvements. Genome-wide mapping using Human Mapping 10K Array showed a single positive locus with a parametric LOD score of 4.92 in a region on chromosome 1p21.1-p13.3. Further analyses using polymorphic microsatellite markers defined a 6.6-Mb critical region containing approximately 130 known genes. This locus is the fourth one linked to ARNSMR.
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PMID:A new locus for autosomal recessive non-syndromic mental retardation maps to 1p21.1-p13.3. 1730 43

Chromosomal rearrangements causing microdeletions and microduplications are a major cause of congenital malformation and mental retardation. Because they are not visible by routine chromosome analysis, high resolution whole-genome technologies are required for the detection and diagnosis of small chromosomal abnormalities. Recently, array-comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) have been useful tools for the identification and mapping of deletions and duplications at higher resolution and throughput. Smith-Magenis syndrome (SMS) is a multiple congenital anomalies/mental retardation syndrome caused by deletion or mutation of the retinoic acid induced 1 (RAI1) gene and is often associated with a chromosome 17p11.2 deletion. We report here on the clinical and molecular analysis of a 10-year-old girl with SMS and moyamoya disease (occlusion of the circle of Willis). We have employed a combination of aCGH, FISH, and MLPA to characterize an approximately 6.3 Mb deletion spanning chromosome region 17p11.2-p13.1 in this patient, with the proximal breakpoint within the RAI1 gene. Further, investigation of the genomic architecture at the breakpoint intervals of this large deletion documented the presence of palindromic repeat elements that could potentially form recombination substrates leading to unequal crossover.
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PMID:Smith-Magenis syndrome and Moyamoya disease in a patient with del(17)(p11.2p13.1). 1743 95

Two siblings from a consanguineous Egyptian marriage showed an identical phenotype of cortical lissencephaly with cerebellar hypoplasia, severe epilepsy, and mental retardation. Examination of karyotype revealed 46, t(7;12)(q22;p13)mat (7;12)(q22;p13)pat in both affected children, suggesting a homozygous reciprocal balanced translocation. Each healthy parent was a carrier of the balanced translocation in the heterozygous state, suggesting homozygous disruption of a gene involved in brain development. There were early spontaneous abortions in this family, as would be expected from transmission of an unbalanced chromosome. A disruption of RELN at 7q22.1 with absence of encoded protein was identified. This is the first demonstration that such rare homozygous translocations can be used to identify recessive disease gene mutations.
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PMID:Identification of a novel recessive RELN mutation using a homozygous balanced reciprocal translocation. 1743

Recent molecular cytogenetic data have shown that the constitution of complex chromosome rearrangements (CCRs) may be more complicated than previously thought. The complicated nature of these rearrangements challenges the accurate delineation of the chromosomal breakpoints and mechanisms involved. Here, we report a molecular cytogenetic analysis of two patients with congenital anomalies and unbalanced de novo CCRs involving chromosome 17p using high-resolution array-based comparative genomic hybridization (array CGH) and fluorescent in situ hybridization (FISH). In the first patient, a 4-month-old boy with developmental delay, hypotonia, growth retardation, coronal synostosis, mild hypertelorism, and bilateral club feet, we found a duplication of the Charcot-Marie-Tooth disease type 1A and Smith-Magenis syndrome (SMS) chromosome regions, inverted insertion of the Miller-Dieker lissencephaly syndrome region into the SMS region, and two microdeletions including a terminal deletion of 17p. The latter, together with a duplication of 21q22.3-qter detected by array CGH, are likely the unbalanced product of a translocation t(17;21)(p13.3;q22.3). In the second patient, an 8-year-old girl with mental retardation, short stature, microcephaly and mild dysmorphic features, we identified four submicroscopic interspersed 17p duplications. All 17 breakpoints were examined in detail by FISH analysis. We found that four of the breakpoints mapped within known low-copy repeats (LCRs), including LCR17pA, middle SMS-REP/LCR17pB block, and LCR17pC. Our findings suggest that the LCR burden in proximal 17p may have stimulated the formation of these CCRs and, thus, that genome architectural features such as LCRs may have been instrumental in the generation of these CCRs.
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PMID:Complex chromosome 17p rearrangements associated with low-copy repeats in two patients with congenital anomalies. 1745 15

We report on a familial duplication in the short arm of chromosome 7, dup(7)(p11.2p12), present in three generations. The duplication was identified by GTG-banding and fluorescence in situ hybridization (FISH) with a whole chromosome 7 DNA painting probe that verified that the duplicated material originated from chromosome 7. The multicolor banding (mBAND) was used to refine the breakpoint assignment. The duplication identified in the proband was also present in her son and mother. All three carriers have mild cognitive deficiencies. Interstitial duplications of the short arm of chromosome 7, although relatively uncommon, have been described in association with a variety of clinical features, including mental retardation of varying severity. Duplication of the p11.2p13 region on chromosome 7 was reported in association with Silver-Russell syndrome (SRS), and an overlapping dup(7)(p11.2p14.1)dn was described in an individual with autistic disorder. Furthermore, a potentially overlapping maternally transmitted inverted duplication, dup(7)(p13p12.2), was reported in patients with cognitive delay. These observations and the phenotype of our duplication carriers suggest that partial trisomy of the proximal 7p region causes cognitive deficiency. The maternal origin of the duplication is of special interest in light of genomic imprinting and implication of the 7p11-p13 region in the SRS etiology. Locus-specific FISH targeting a growth factor receptor binding protein 10 (GRB10), the strong candidate for SRS residing at 7p12.2, showed that it is not duplicated in our patients. Our study helps refine the SRS critical region on 7p and extends our understanding of the clinical manifestations associated with 7p duplications.
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PMID:Maternally inherited duplication of chromosome 7, dup(7)(p11.2p12), associated with mild cognitive deficit without features of Silver-Russell syndrome. 1755 27


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