Cri-du-Chat Syndrome
Chromosomes, Human, Pair 5
Microcephaly
22q11 Deletion Syndrome
A neuropsychological-genetic profile of atypical cri du chat syndrome: implications for prognosis. (1/39)
Cri du chat syndrome is associated with a deletion on the short arm of chromosome 5. The main diagnostic feature is a high pitched, cat-like cry which has recently been localised to 5p15.3 and is separate from the remaining clinical features of the syndrome, which have been localised to 5p15.2. The present study describes a family of four who have a deletion slightly distal (5p15.3) to the critical region. Detailed neuropsychological evaluations indicated a similar pattern of cognitive performance to that reported for subjects with typical CDCS but with only minimal intellectual impairment. In addition, in this family the 5p deletion is transmitted in an autosomal dominant fashion, contrasting with most cases of CDCS, which are either de novo or occur as an unbalanced product of a balanced translocation in a normal parent. This study confirms the importance of differentiating between 5p deletions that coincide with the typical cri du chat phenotype which includes severe to profound learning disability and deletions that only delete the distal critical region that coincides with a milder degree of cognitive impairment and a much improved prognosis. (+info)Cri-du-chat syndrome: clinical profile and prenatal diagnosis. (2/39)
Prenatal diagnosis of cri-du-chat syndrome is described in 2 pregnancies. In Case 1, the mother was a balanced translocation carrier and had 2 previously affected off springs. Prenatal diagnosis by chorion villus sampling and cordocentesis was successful in diagnosing an affected conceptus and the pregnancy was electively terminated. Case 2 was referred for nonimmune foetal hydrops and cordocentesis revealed deletion 5p. This second case was noteworthy for the fact that deletion 5p has not been reported to cause foetal hydrops. (+info)Clinical and molecular characterisation of 80 patients with 5p deletion: genotype-phenotype correlation. (3/39)
The majority of deletions of the short arm of chromosome 5 are associated with cri du chat syndrome (CdCS) and patients show phenotypic and cytogenetic variability. To perform a genotype-phenotype correlation, 80 patients from the Italian CdCS Register were analysed. Molecular cytogenetic analysis showed that 62 patients (77.50%) had a 5p terminal deletion characterised by breakpoint intervals ranging from p13 (D5S763) to p15.2 (D5S18). Seven patients (8.75%) had a 5p interstitial deletion, four (5%) a de novo translocation, and three (3.75%) a familial translocation. Of the remaining four patients, three (3.75%) had de novo 5p anomalies involving two rearranged cell lines and one (1.25%) had a 5p deletion originating from a paternal inversion. The origin of the deleted chromosome 5 was paternal in 55 out of 61 patients (90.2%). Genotype-phenotype correlation in 62 patients with terminal deletions highlighted a progressive severity of clinical manifestation and psychomotor retardation related to the size of the deletion. The analysis of seven patients with interstitial deletions and one with a small terminal deletion confirmed the existence of two critical regions, one for dysmorphism and mental retardation in p15.2 and the other for the cat cry in p15.3. Results from one patient permitted the cat cry region to be distally narrowed from D5S13 to D5S731. Furthermore, this study lends support to the hypothesis of a separate region in p15.3 for the speech delay. (+info)Growth study of cri du chat syndrome. (4/39)
We compared the growth of children with cri du chat (5p-) syndrome with the 1990 UK growth curves. Most subjects had impaired growth, particularly of head circumference. The more emaciated the child the more pronounced the microcephaly, showing the need for growth and nutrition monitoring. (+info)Deletion of the telomerase reverse transcriptase gene and haploinsufficiency of telomere maintenance in Cri du chat syndrome. (5/39)
Cri du chat syndrome (CdCS) results from loss of the distal portion of chromosome 5p, where the telomerase reverse transcriptase (hTERT) gene is localized (5p15.33). hTERT is the rate-limiting component for telomerase activity that is essential for telomere-length maintenance and sustained cell proliferation. Here, we show that a concomitant deletion of the hTERT allele occurs in all 10 patients with CdCS whom we examined. Induction of hTERT mRNA in proliferating lymphocytes derived from five of seven patients was lower than that in unaffected control individuals (P<.05). The patient lymphocytes exhibited shorter telomeres than age-matched unaffected individuals (P<.0001). A reduction in replicative life span and a high rate of chromosome fusions were observed in cultured patient fibroblasts. Reconstitution of telomerase activity by ectopic expression of hTERT extended the telomere length, increased the population doublings, and prevented the end-to-end fusion of chromosomes. We conclude that hTERT is limiting and haploinsufficient for telomere maintenance in humans in vivo. Accordingly, the hTERT deletion may be one genetic element contributing to the phenotypic changes in CdCS. (+info)Heterozygous telomerase deficiency in mouse and man: when less is definitely not more. (6/39)
Telomerase, whose core components are a reverse transcriptase (TERT) and an integral RNA (TERC) maintains telomere ends. In somatic cells in the absence of telomerase telomeres get shorter leading to replicative cell senescence. In cancer cells abundant telomerase is present and cells do not senesce. Hence levels of telomerase may be crucial in regulating senescence and the transition to the neoplastic state. Heterozygous TERC mutations in man have been shown to underlie the rare inherited skin and bone marrow failure condition dyskeratosis congenita and a number of patients initially classified as idiopathic aplastic anemia have also been found to be mutated in one allele of the TERC gene. Families in which TERC mutations are segregating show disease anticipation, the severity of the disease increasing in successive generations due to decreasing telomere length. These data, along with biochemical analysis of mutated Terc and studies of Terc deficient mice show that in man and mouse haploinsufficiency for TERC leads to inability to correctly maintain telomeres, and highlights the importance of finely controlled telomerase levels in striking a balance between the processes of aging and cancer. Here we review several scenarios in which telomerase levels are disturbed, in human diseases or following genetic manipulation in mice. (+info)High-resolution mapping of genotype-phenotype relationships in cri du chat syndrome using array comparative genomic hybridization. (7/39)
We have used array comparative genomic hybridization to map DNA copy-number changes in 94 patients with cri du chat syndrome who had been carefully evaluated for the presence of the characteristic cry, speech delay, facial dysmorphology, and level of mental retardation (MR). Most subjects had simple deletions involving 5p (67 terminal and 12 interstitial). Genotype-phenotype correlations localized the region associated with the cry to 1.5 Mb in distal 5p15.31, between bacterial artificial chromosomes (BACs) containing markers D5S2054 and D5S676; speech delay to 3.2 Mb in 5p15.32-15.33, between BACs containing D5S417 and D5S635; and the region associated with facial dysmorphology to 2.4 Mb in 5p15.2-15.31, between BACs containing D5S208 and D5S2887. These results overlap and refine those reported in previous publications. MR depended approximately on the 5p deletion size and location, but there were many cases in which the retardation was disproportionately severe, given the 5p deletion. All 15 of these cases, approximately two-thirds of the severely retarded patients, were found to have copy-number aberrations in addition to the 5p deletion. Restriction of consideration to patients with only 5p deletions clarified the effect of such deletions and suggested the presence of three regions, MRI-III, with differing effect on retardation. Deletions including MRI, a 1.2-Mb region overlapping the previously defined cri du chat critical region but not including MRII and MRIII, produced a moderate level of retardation. Deletions restricted to MRII, located just proximal to MRI, produced a milder level of retardation, whereas deletions restricted to the still-more proximal MRIII produced no discernible phenotype. However, MR increased as deletions that included MRI extended progressively into MRII and MRIII, and MR became profound when all three regions were deleted. (+info)Determination of the 'critical region' for cat-like cry of Cri-du-chat syndrome and analysis of candidate genes by quantitative PCR. (8/39)
Cri-du-chat (CDC, OMIM 123450) is a chromosomal syndrome that results from partial deletions on the short arm of chromosome 5. The clinical features of CDC normally include high-pitched cat-like cry, mental retardation, microcephaly, hypertelorism and epicanthic folds. The cat-like cry is the most prominent clinical characteristic in newborn children and is usually considered as diagnostic for the CDC syndrome. Using a strategy of 'phenotype dissection', the critical region for cat-like cry was mapped to the chromosomal segment 5p15.3-5p15.2 in previous reports. In this study, the distal breakpoints of two interstitial deletions in two clinical distinctive CDC patients are analysed, one with and one without the cat-like cry. Using PCR, the critical region for the cat-like cry is mapped to a short 640 kbp region on chromosome 5p. Genome analysis of this critical region reveals a gene-rich sequence containing five known genes, five putative genes and three spliced EST sequences, altogether 71 predicted exons. Three genes, FLJ25076, a homolog to a ubiquitin-conjugating enzyme UBC-E2, FLJ20303, a nucleolar protein NOP2, which may play a role in the regulation of the cell cycle and MGC5309, a protein with similarity to Nut2, a Drosophila transcriptional coactivator, have been characterized and expression profiles determined by quantitative PCR. These results suggest that one candidate gene, FLJ25076, encodes a ubiquitin-conjugated enzyme E2 type, which is locally expressed in thoracic and scalp tissues. The other two genes are expressed uniformly in all tissues tested, which suggest that they are housekeeping genes. (+info)Cri-du-chat syndrome is a genetic disorder caused by a deletion of part of chromosome 5. The name "Cri-du-chat" means "cry of the cat" in French, and refers to the characteristic high-pitched, distinctive cry of affected infants, which sounds similar to the meow of a cat.
The symptoms of Cri-du-chat syndrome can vary widely in severity, but typically include intellectual disability, developmental delays, speech and language difficulties, low muscle tone, and distinctive facial features such as wide-set eyes, a shortened jaw, and a rounded nose. Affected individuals may also have hearing and vision problems, heart defects, and gastrointestinal issues.
Cri-du-chat syndrome is usually not inherited and occurs randomly during the formation of the egg or sperm. It affects approximately 1 in 20,000 to 50,000 newborns worldwide. There is no cure for Cri-du-chat syndrome, but early intervention with therapies such as speech and language therapy, physical therapy, and occupational therapy can help improve outcomes and quality of life for affected individuals.
Human chromosome pair 5 consists of two rod-shaped structures present in the nucleus of human cells, which contain genetic material in the form of DNA and proteins. Each member of chromosome pair 5 is a single chromosome, and humans typically have 23 pairs of chromosomes for a total of 46 chromosomes in every cell of their body (except gametes or sex cells, which contain 23 chromosomes).
Chromosome pair 5 is one of the autosomal pairs, meaning it is not a sex chromosome. Each member of chromosome pair 5 is approximately 197 million base pairs in length and contains around 800-900 genes that provide instructions for making proteins and regulating various cellular processes.
Chromosome pair 5 is associated with several genetic disorders, including cri du chat syndrome (resulting from a deletion on the short arm of chromosome 5), Prader-Willi syndrome and Angelman syndrome (both resulting from abnormalities in gene expression on the long arm of chromosome 5).
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
Microcephaly is a medical condition where an individual has a smaller than average head size. The circumference of the head is significantly below the normal range for age and sex. This condition is typically caused by abnormal brain development, which can be due to genetic factors or environmental influences such as infections or exposure to harmful substances during pregnancy.
Microcephaly can be present at birth (congenital) or develop in the first few years of life. People with microcephaly often have intellectual disabilities, delayed development, and other neurological problems. However, the severity of these issues can vary widely, ranging from mild to severe. It is important to note that not all individuals with microcephaly will experience significant impairments or challenges.
22q11 Deletion Syndrome, also known as DiGeorge Syndrome or Velocardiofacial Syndrome, is a genetic disorder caused by the deletion of a small piece of chromosome 22 at a specific location (q11.2). This deletion results in the poor development of several body systems, including the following:
* The third and fourth pharyngeal pouches, which give rise to various structures in the neck, such as the parathyroid glands and thymus. As a result, affected individuals often have hypocalcemia (low levels of calcium in the blood) due to decreased parathyroid hormone production, and may have immune deficiencies due to abnormal or missing thymus tissue.
* The fourth pharyngeal arch, which forms parts of the aortic arch, the cranial base, and the neck. This can lead to congenital heart defects, such as tetralogy of Fallot or interrupted aortic arch.
* The branchial arches, which contribute to the formation of the face and neck. This can result in distinctive facial features, such as a prominent nasal bridge, hooded eyelids, a small jaw, and low-set ears.
The severity of 22q11 Deletion Syndrome can vary widely, even among members of the same family. Common symptoms include heart defects, palate abnormalities, immune deficiencies, developmental delays, learning disabilities, behavioral problems, and hearing loss. Some individuals with this syndrome may also have psychiatric disorders, such as schizophrenia or anxiety disorders.
Treatment for 22q11 Deletion Syndrome typically involves a multidisciplinary approach, addressing each of the affected body systems. For example, heart defects may require surgical repair, while immune deficiencies may be managed with medications or thymus transplantation. Calcium supplements and vitamin D may be prescribed to treat hypocalcemia. Speech therapy, occupational therapy, and special education services can help address developmental delays and learning disabilities.
'Abnormalities, Multiple' is a broad term that refers to the presence of two or more structural or functional anomalies in an individual. These abnormalities can be present at birth (congenital) or can develop later in life (acquired). They can affect various organs and systems of the body and can vary greatly in severity and impact on a person's health and well-being.
Multiple abnormalities can occur due to genetic factors, environmental influences, or a combination of both. Chromosomal abnormalities, gene mutations, exposure to teratogens (substances that cause birth defects), and maternal infections during pregnancy are some of the common causes of multiple congenital abnormalities.
Examples of multiple congenital abnormalities include Down syndrome, Turner syndrome, and VATER/VACTERL association. Acquired multiple abnormalities can result from conditions such as trauma, infection, degenerative diseases, or cancer.
The medical evaluation and management of individuals with multiple abnormalities depend on the specific abnormalities present and their impact on the individual's health and functioning. A multidisciplinary team of healthcare professionals is often involved in the care of these individuals to address their complex needs.