| 3q29 microdeletion syndrome | |
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| Other names | 3qter deletion, Monosomy 3q29 |
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| Chromosome 3 is associated with this condition | |
3q29 microdeletion syndrome is a rare genetic disorder resulting from the deletion of a segment of chromosome 3. This syndrome was first described in 2005. [1] [2]
The clinical phenotype of 3q29 microdeletion syndrome is variable. Clinical features can include mild to moderate intellectual disability with mildly dysmorphic facial features (long and narrow face, short philtrum and a high nasal bridge). In 6 reported patients, additional features including autism, ataxia, chest-wall deformity and long, tapering fingers were found in at least two patients. [1] A review of 14 children with interstitial deletions of 3q29, found 11 who had the common recurrent 1.6Mb deletion and displayed intellectual disability and microcephaly. [3]
The variability of phenotype is underscored by the report on a 6 and 9/12 year-old male patient with a de novo chromosome 3q29 microdeletion identified by BAC array comparative genomic hybridization assay (aCGH), with accompanying normal 46,XY high-resolution chromosome analysis. The patient has language-based learning disabilities and behavioral features consistent with diagnoses of autism and attention deficit hyperactivity disorder (ADHD) of the inattentive type. He also displays some other features previously associated with chromosome 3q29 microdeletion such as an elongated face, long fingers, and joint laxity. Most notably the patient, per formal IQ testing, did not have an intellectual disability. The patient demonstrated an average full-scale IQ result. This is notable because previously reported patients with chromosome 3q29 terminal deletion had intellectual disabilities. This report further expands the phenotypic spectrum to include the possibility of normal intelligence as corroborated by formal, longitudinal psycho-educational testing. [4]
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Research on the risk for developing schizophrenia showed that 3q29 microdeletion syndrome leads to a significant higher rate of schizophrenia. [5] In addition, a deletion at 3q29 was found to confer an increase to the odds of developing schizophrenia in a study of copy number variants and their effect on that disorder. [6]
The 3q29 Project at Rutgers University is focused on understanding the phenotypic spectrum, natural history, and molecular mechanism of 3q29 deletion syndrome .
Patient-centered information and resources are available through rarechromo.org and the 3q29 Foundation. Individuals with the 3q29 deletion who are interested in participating in research can join the 3q29 registry.
Wolf–Hirschhorn syndrome (WHS) is a chromosomal deletion syndrome resulting from a partial deletion on the short arm of chromosome 4 [del(4)(p16.3)]. Features include a distinct craniofacial phenotype and intellectual disability.
Smith–Magenis syndrome (SMS), also known as 17p-microdeletion syndrome, is a microdeletion syndrome characterized by an abnormality in the short (p) arm of chromosome 17. It has features including intellectual disability, facial abnormalities, difficulty sleeping, and numerous behavioral problems such as self-harm. Smith–Magenis syndrome affects an estimated between 1 in 15,000 to 1 in 25,000 individuals.
22q13 deletion syndrome, known as Phelan–McDermid syndrome (PMS), is a genetic disorder caused by deletions or rearrangements on the q terminal end of chromosome 22. Any abnormal genetic variation in the q13 region that presents with significant manifestations (phenotype) typical of a terminal deletion may be diagnosed as 22q13 deletion syndrome. There is disagreement among researchers as to the exact definition of 22q13 deletion syndrome. The Developmental Synaptopathies Consortium defines PMS as being caused by SHANK3 mutations, a definition that appears to exclude terminal deletions. The requirement to include SHANK3 in the definition is supported by many but not by those who first described 22q13 deletion syndrome.
2p15-16.1 microdeletion is an extremely rare genetic disorder caused by a small deletion in the short arm of human chromosome 2. First described in two patients in 2007, by 2013 only 21 people have been reported as having the disorder in the medical literature.
Potocki–Lupski syndrome (PTLS), also known as dup(17)p11.2p11.2 syndrome, trisomy 17p11.2 or duplication 17p11.2 syndrome, is a contiguous gene syndrome involving the microduplication of band 11.2 on the short arm of human chromosome 17 (17p11.2). The duplication was first described as a case study in 1996. In 2000, the first study of the disease was released, and in 2007, enough patients had been gathered to complete a comprehensive study and give it a detailed clinical description. PTLS is named for two researchers involved in the latter phases, Drs. Lorraine Potocki and James R. Lupski of Baylor College of Medicine.
Koolen–De Vries syndrome (KdVS), also known as 17q21.31 microdeletion syndrome, is a rare genetic disorder caused by a deletion of a segment of chromosome 17 which contains six genes. This deletion syndrome was discovered independently in 2006 by three different research groups.
DECIPHER is a web-based resource and database of genomic variation data from analysis of patient DNA. It documents submicroscopic chromosome abnormalities and pathogenic sequence variants, from over 25000 patients and maps them to the human genome using Ensembl or UCSC Genome Browser. In addition it catalogues the clinical characteristics from each patient and maintains a database of microdeletion/duplication syndromes, together with links to relevant scientific reports and support groups.
8p23.1 duplication syndrome is a rare genetic disorder caused by a duplication of a region from human chromosome 8. This duplication syndrome has an estimated prevalence of 1 in 64,000 births and is the reciprocal of the 8p23.1 deletion syndrome. The 8p23.1 duplication is associated with a variable phenotype including one or more of speech delay, developmental delay, mild dysmorphism, with prominent forehead and arched eyebrows, and congenital heart disease (CHD).
Non-allelic homologous recombination (NAHR) is a form of homologous recombination that occurs between two lengths of DNA that have high sequence similarity, but are not alleles.
1q21.1 deletion syndrome is a rare aberration of chromosome 1. A human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 deletion syndrome, one chromosome of the pair is not complete, because a part of the sequence of the chromosome is missing. One chromosome has the normal length and the other is too short.
1q21.1 duplication syndrome, also known as 1q21.1 microduplication, is an uncommon copy number variant associated with several congenital abnormalities, including developmental delay, dysmorphic traits, autism spectrum disorder, and congenital cardiac defects. Common facial features include frontal bossing, hypertelorism, and macrocephaly. Around 18 and 29% of patients with 1q21.1 microduplications have congenital cardiac abnormalities. 1q21.1 duplication syndrome is caused by microduplications of the BP3-BP4 region. 18-50% are de novo deletions and 50-82% inherited from parents. The 1q21.1 area, one of the largest regions in the human genome, is highly susceptible to copy number variation due to its frequent low-copy duplications. Whole exon sequencing and quantitative polymerase chain reaction can provide a precise molecular diagnosis for children with 1q21.1 microduplication syndrome.
2q37 monosomy is a rare genetic disorder caused by a deletion of a segment at the end of chromosome 2.
22q11.2 duplication syndrome is a rare genetic disorder caused by a duplication of a segment at the end of chromosome 22.
Distal 18q- is a genetic condition caused by a deletion of genetic material within one of the two copies of chromosome 18. The deletion involves the distal section of 18q and typically extends to the tip of the long arm of chromosome 18.
The genotype-first approach is a type of strategy used in genetic epidemiological studies to associate specific genotypes to apparent clinical phenotypes of a complex disease or trait. As opposed to “phenotype-first”, the traditional strategy that has been guiding genome-wide association studies (GWAS) so far, this approach characterizes individuals first by a statistically common genotype based on molecular tests prior to clinical phenotypic classification. This method of grouping leads to patient evaluations based on a shared genetic etiology for the observed phenotypes, regardless of their suspected diagnosis. Thus, this approach can prevent initial phenotypic bias and allow for identification of genes that pose a significant contribution to the disease etiology.
Burnside–Butler syndrome is a name that has been applied to the effects of microdeletion of DNA sequences involving four neurodevelopmental genes. Varying developmental and psychiatric disorders have been attributed to the microdeletion; however, the great majority of people with the deletion do not have any clinical features associated with it. More studies are needed to delineate the range of clinical presentation.
17q12 microdeletion syndrome, also known as 17q12 deletion syndrome, is a rare chromosomal anomaly caused by the deletion of a small amount of material from a region in the long arm of chromosome 17. It is typified by deletion of the HNF1B gene, resulting in kidney abnormalities and renal cysts and diabetes syndrome. It also has neurocognitive effects, and has been implicated as a genetic factor for autism and schizophrenia.
Ring chromosome 22, also known as ring 22, is a rare chromosomal disorder. Ring chromosomes occur when the ends of a chromosome lose material and fuse into a ring shape; in the case of ring 22, this occurs for chromosome 22, the last numbered human autosome. Ring chromosome 22 is marked by a number of consistent traits, such as intellectual disability, speech delay, hypotonia, and hyperactivity. The condition has a similar phenotype to Phelan-McDermid syndrome, as the loss of the SHANK3 gene is implicated in both.
DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a syndrome caused by a microdeletion on the long arm of chromosome 22. While the symptoms can vary, they often include congenital heart problems, specific facial features, frequent infections, developmental disability, intellectual disability and cleft palate. Associated conditions include kidney problems, schizophrenia, hearing loss and autoimmune disorders such as rheumatoid arthritis or Graves' disease.
16p11.2 deletion syndrome is a rare genetic condition caused by microdeletion on the short arm of chromosome 16. Most affected individuals experience global developmental delay and intellectual disability, as well as childhood-onset obesity. 16p11.2 deletion is estimated to account for approximately 1% of autism spectrum disorder cases.