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Chromosome duplication disorders

Chromosome Disorders . 15q13.3 microdeletion syndrome 16p11.2 deletion syndrome 17q23.1q23.2 microdeletion syndrome 1q duplications Chromosome 1p duplication Chromosome 1p36 deletion syndrome Chromosome 1q deletion Chromosome 1q21.1 duplication syndrome Chromosome 20 trisom 22q11.2 duplication syndrome is a condition caused by an extra copy of a small piece of chromosome 22 which contains about 30 to 40 genes. The features of this condition vary widely, even among members of the same family (intrafamilial variability) Chromosome 22q duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the long arm (q) of chromosome 22. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved

Chromosome 15q duplication is a chromosome abnormality that occurs when an extra (duplicate) copy of the genetic material located on the long arm (q) of chromosome 15 is present in each cell. The severity of the condition and the associated signs and symptoms vary based on the size and location of the duplication and which genes are involved Microdeletion and microduplication syndromes are disorders caused by submicroscopic deletions or duplications of contiguous genes on particular parts of chromosomes. Postnatal diagnosis is suspected by clinical appearance and preferably confirmed by chromosomal microarray analysis or by fluorescent in situ hybridization 15q11-q13 duplication syndrome (dup15q syndrome) is a developmental disorder; its signs and symptoms vary among affected individuals. Poor muscle tone (hypotonia) is common in individuals with dup15q syndrome and contributes to delayed development and impairment of motor skills, including sitting and walking Genomic disorders are diseases that result from the loss or gain of chromosomal/DNA material. The most common and better delineated genomic disorders are divided in two main categories: those resulting from copy number losses (deletion syndromes) and those resulting from copy number gains (duplication syndromes) Description: Turner syndrome (TS) occurs when one of the two X chromosomes in females is either missing or incomplete. The most common symptoms are short stature and gonadal dysgenesis, which can cause incomplete sexual development and ovarian failure and infertility. As of right now, there is no known cause of TS

Chromosome/gene and type of disorder e.g. deletion, duplication, variant. Tell us more. Unique is a small charity supporting, informing and networking with families living with a Rare Chromosome Disorder or some Autosomal Dominant Single Gene Disorders associated with learning disability and developmental delay, among other symptoms.. MECP2 duplication syndrome is a rare genetic neurodevelopmental disorder characterized by a wide variety of symptoms including low muscle tone (hypotonia), potentially severe intellectual disability, developmental delays, recurrent respiratory infections, speech abnormalities, seizures, and progressive spasticity, a condition characterized by muscle stiffness that is worsened with movement and can be associated with involuntary muscle spasms (Definition/Background Information) Chromosome 22q Duplication Syndrome is a genetic disorder manifested at birth, with wide-ranging but highly variable signs and symptoms depending on the specific nature of the chromosomal abnormality (size and location of duplication) and the genes involve Chromosome 18q- syndrome (also known as Chromosome 18, Monosomy 18q) is a rare chromosomal disorder in which there is deletion of part of the long arm (q) of chromosome 18. Associated symptoms and findings may vary greatly in range and severity from case to case

Chromosome Disorders Genetic and Rare Diseases

22q11.2 duplication syndrome Genetic and Rare Diseases ..

COVID-19 is an emerging, rapidly evolving situation. Get the latest public health information from CDC: https://www.coronavirus.gov (link is external) Get the latest research information from NIH: https://covid19.nih.gov (link is external Partial chromosome 7 duplication with a phenotype mimicking the HOXA1 spectrum disorder PTPRN2 is not yet linked to a genetic syndrome, although its expression has been identified in the adult human brain, in certain tumors, and in association with type 1 diabetes mellitus A recent study reported that ≍ 5% of all chromosome abnormalities are deletions, including microdeletions, giving a prevalence of 1.99 per 10,000 births. Duplications are even less common, showing a prevalence of 0.7 per 10,000 births and representing ≍ 2% of all the chromosome abnormalities identified ( Wellesley et al., 2012 ) Chromosomal disorders. The following conditions are caused by changes in the structure or number of copies of chromosome 7: Williams syndrome is caused by the deletion of genetic material from a portion of the long (q) arm of chromosome 7. The deleted region, which is located at position 11.23 (written as 7q11.23), is designated as the Williams. A duplication of Chromosome 22q13 is a very rare genetic condition in which the cells of the body have a small but variable amount of extra genetic material from one of the body's 46 chromosomes - chromosome 22

At present, Xia-Gibbs syndrome has been reported to be mainly caused by truncating mutations in AHDC1 gene located on chromosome 1p36.11. However, the evidence supporting AHDC1 deletion as a cause of this syndrome is still limited. Here we report an 8-year-old boy carrying a de novo 575 Kb microdeletion at 1p36.11 including AHDC1 gene MECP2 duplication syndrome is caused by a genetic change in which there is an extra copy of the MECP2 gene in each cell. This extra copy of the MECP2 gene is caused by a duplication of genetic material on the long (q) arm of the X chromosome. The size of the duplication varies from 100,000 to a few million DNA building blocks (base pairs). The MECP2 gene is always included in this duplication. Below you will find our free Information Guides to specific chromosome and gene disorders, as well as guides translated into various languages. Do scroll down to the bottom of the 'Chromosome Disorder Guides - English' table to view guides and reports on a wide range of related general topics like DNA sequencing, deletions and. In 1986, Schmickel3 first described contiguous gene syndromes (CGS) as involvement of multiple genes located in close proximity to each other on a chromosome. This term has been refined over the years and expanded to include a group of disorders defined by a deletion or duplication of a chromosomal segment spanning more than one disease gene, each affecting the phenotype independently In trisomy, the genetic makeup involves one chromosome having three copies instead of two (a total of 47 chromosomes). This is the most common type of aneuploidy. 1. Down syndrome (Trisomy 21) Down syndrome is the most common form of trisomy. For every 733 babies that are born, one newborn is affected. In this disorder, there are three copies.

Chromosome 22q duplication Genetic and Rare Diseases

MECP2 duplication syndrome is caused by a genetic change in which there is an extra copy of the MECP2 gene in each cell. This extra copy of the MECP2 gene is caused by a duplication of genetic material on the long (q) arm of the X chromosome. The size of the duplication varies from 100,000 to a few million DNA building blocks (base pairs). The MECP2 gene is always included in this duplication. A chromosome 5q35 duplication is a rare genetic condition in which there is an extra copy of part of the genetic material that makes up one of the body's 46 chromosomes - chromosome 5. A duplication is also called a partial trisomy. As with other chromosome disorders, having an extra piece of genetic material may increase the risk of birth. Chromosomal aberration is a condition in which deletion or duplication of a particular chromosome in a set, lead to monosomy, nullisomy, trisomy, tetrasomy. Some disorders in human being due to chromosomal aberrations are as follows: Klinefelter syndrome (XXY) It is due to a trisomic condition in sex chromosomes, a person has XXY chromosomes duplication of chromosome 5. (q31.2) shows the part of the chromosome that is duplicated; in this case, there is a gain of a chromosome segment in band q31.2. The duplication occurred dn or de novo (as a 'new event'): the parents' chromosomes have been checked and no duplication or other chromosome Duplications of chromosome 3q A duplication of 3q is a rare genetic condition caused by having an extra part of one of the body's 46 chromosomes. For healthy development, chromosomes should contain just the right amount of material - not too much and not too little. Extr

In the case of this syndrome the genetic anomaly specifically affects the chromosome 13, that is to say that it has three copies of the same chromosome. 3 - Down Syndrome or Trisomy 21 . The known Down Syndrome or Trisomy 21 Is a genetic disorder caused by the presence of an extra copy of chromosome 21. It is the most frequent chromosomal. CHROMOZOM 17Q11.2 DUPLICATION - Rare diseases and genetic disorders. Good morning to all. We are the grand parents of a 1 year old little man who was diagnosed with a genetic duplication known as 17Q11.2. Our son (the father) was told that only a few people in the WORLD have been diagnosed, therefore very difficult to find information regarding. Deletions- A section of a chromosome is missing. This can be referred to as a deletion, partial deletion, partial monosomy, distal monosomy or terminal deletion. Duplications - Part of the chromosome is duplicated so a person has extra genetic material. Translocations - A section of one chromosome is transferred to a different chromosome Chromosome Disorders. Summary. Chromosome 7p duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the short arm (p) of chromosome 7. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved

Chromosome 15q duplication Genetic and Rare Diseases

  1. Chromosome 9p Duplication Syndrome may not be preventable, since it is a genetic disorder. Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnanc
  2. Chromosome 6q Duplication Syndrome may not be preventable, since it is a genetic disorder. Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnanc
  3. Introduction: Duplication of long arm of chromosome 7(q) is uncommon. It may occur as pure, isolated anomaly or in association with other mutations involving the same or other chromosomes. Pure chromosome 7q duplication has recently been classified by segment involved: the interstitial, proximal, or distal segment of the arm

Microdeletion and Microduplication Syndromes - Pediatrics

15q11-q13 duplication syndrome: MedlinePlus Genetic

  1. Physicians, genetic counselors, therapists and other healthcare professionals, register now to help us learn more about rare chromosome disorders: the associated symptoms, new research and evolving treatments. Request notifications of new studies and important publications on our website. Professional contact information will appear on the CDO.
  2. Chromosome Disorder Outreach, Inc is a non-profit organization. Founded, supported, and run by parents just like you, for over 29 years CDO has been supporting those born with rare chromosome and gene mutation disorders. Help us continue this vital work. Alone we may go unnoticed, together our intensity cannot be missed
  3. Rare Chromosome Disorder Support Group. Duplications of 16p. Updated 2007. National Center for Advancing Translational Sciences Genetic and Rare Diseases Information Center. Chromosome 16q deletion. Updated February 9, 2016. Sousa B, Rocha G, Doria S, Alves JR, Guedes B, Guimarães H. New findings in partial trisomy 16q: clinical report
  4. Most cases of 22q 11.2 deletion and duplication syndromes occur at random and aren't inherited or related to any identifiable cause. However, approximately 5-10 percent of children with a 22q11.2 deletion inherit it from a parent who has a mild — usually undiagnosed — form of the disorder
  5. Duplication. Duplication disorders occur where a portion of a chromosome is duplicated. The chromosome contains twice the number of copies of that gene. One example is Charcot-Marie-Tooth, which can be caused by a duplication of the short arm of chromosome 17

Lejeune and Turpin (1960) demonstrated that trisomy of human chromosome 21 caused the constellation of findings recognized as Down syndrome ().This chromosome disorder was the first to be described and is the most common viable autosomal trisomy, occurring in approximately 1 in 700-800 live births ().The vast majority (>90%) occur secondary to meiotic nondisjunction, and a pronounced. Charcot-Marie-Tooth disease. Duplication of a small piece of chromosome 17 at position p12 that includes the PMP22 gene causes most cases of a disorder called Charcot-Marie-Tooth disease. When this disorder is caused by changes affecting the PMP22 gene, it is called Charcot-Marie-Tooth disease type 1A, or CMT1A. Charcot-Marie-Tooth disease damages the peripheral nerves, which connect the brain. The chromosome 16p13.11 heterozygous deletion is associated with a diverse array of neuropsychiatric disorders including intellectual disabilities, autism, schizophrenia, epilepsy and attention.

chromosome 22 duplication. 29. Jun. Cardiac evaluation of patients with 22q11.2 duplication syndrome. Donate now to increase awareness and research into chromosome disorders. Chromosome Disorder Outreach is a 501(c)(3) non-profit organization. Your gift is tax deductible as provided by law. Florida Reg CH1120 Chromosomal disorders are due to the change in the number of chromosomes present. This can be categorised into various types: Aneuploidy: loss or gain of a chromosome. This happens due to non-disjunction of chromatids when chromatids fail to separate during cell division. This results in one gamete having two copies of one chromosome and the.

Microduplication syndromes - UpToDat

  1. Duplications: A portion of the chromosome has been duplicated, resulting in extra genetic material. Known human disorders include Charcot-Marie-Tooth disease type 1A, which may be caused by duplication of the gene encoding peripheral myelin protein 22 (PMP22) on chromosome 17
  2. ed by the size of the duplicated genetic portion
  3. Chromosome 19p Deletion Syndrome is a chromosome abnormality that occurs when there is a missing (deleted) copy of genetic material on the short arm (p) of chromosome 19. The severity of the condition and the signs and symptoms depend on the size and location of the deletion and which genes are involved. Features that often occur in people with.
  4. ant. 4. TEXT. A number sign (#) is used with this entry because of evidence that split-hand/foot malformation with long bone deficiency-3 (SHFLD3) is associated with a duplication involving one or more genes on chromosome 17p13.3. The duplication is less than 50% penetrant and shows markedly variable expressivity.
  5. Dup15q syndrome is the common name for chromosome 15q11.2-q13.1 duplication syndrome. This is a neurodevelopmental disorder, caused by the partial duplication of Chromosome 15, that confers a strong risk for autism spectrum disorder, epilepsy, and intellectual disability. It is the most common genetic cause of autism, accounting for approximately 1-3% of cases
  6. This is a very basic video about Chromosome Disorders. It talks about what Chromosomes are, different types of disorders, and basic Q&A for families with a n..

A new study by a US research consortium has discovered that a small segment of chromosome 16 is either missing or duplicated in about 1 per cent of people with an autism spectrum disorder (ASD. FOXP2-related speech and language disorder. Several different changes affecting chromosome 7 can result in FOXP2-related speech and language disorder.These changes involve a region of the long (q) arm of chromosome 7 containing the FOXP2 gene.FOXP2-related speech and language disorder is an uncommon condition that affects the development of speech and language starting in early childhood 1q21.1 duplication syndrome or 1q21.1 (recurrent) microduplication is a rare aberration of chromosome 1.. In a common situation a human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 duplication syndrome one chromosome of the pair is over complete, because a part of the sequence of the chromosome is duplicated twice or more

Genetic counseling. MECP2 disorders are inherited in an X-linked manner. More than 99% are simplex cases (i.e., a single occurrence in a family), resulting from a de novo pathogenic variant or possibly from inheritance of the pathogenic variant from a parent who has germline mosaicism.Rarely, a MECP2 variant may be inherited from a heterozygous mother in whom favorable skewing of X-chromosome. Trisomy 22 is a chromosomal disorder in which there are three copies of chromosome 22 rather than two. It is a frequent cause of spontaneous abortion during the first trimester of pregnancy.Progression to the second trimester and live birth are rare. This disorder is found in individuals with an extra copy or a variation of chromosome 22 in some or all cells of their body Chromosome Disorder Outreach Inc. is a non-profit 501C3 charitable organization which was founded in 1992 by a group of seven parents raising children born with rare chromosome disorders. The Genetic Alliance helped CDO get its start that year, and CDO was approved as a member of the National Organization of Rare Disorders (NORD) in 1998

Chromosome 12 Q Duplication Disorders. 26 likes. First time mother with Dizygotic twins with Dandy Walker malformatio • Trisomy 13 (patau syndrome) • Trisomy 13 is a type of chromosome disorder characterized by having 3 copies of chromosome 13 in cells of the body, instead of the usual 2 copies. • Not inherited. • Affects one in twenty thousand live birth

Deletion and duplication of 16p11.2 (BP4-BP5) have been associated with an increased risk of intellectual disability and psychiatric disorder. This is the first study to compare the frequency of. Chromosome 5 is one of the 23 pairs of chromosomes in humans.People normally have two copies of this chromosome. Chromosome 5 spans about 181 million base pairs (the building blocks of DNA) and represents almost 6% of the total DNA in cells.Chromosome 5 is the 5th largest human chromosome, yet has one of the lowest gene densities.This is partially explained by numerous gene-poor regions that.

13 chromosomal disorders you may not have heard of

Chromosome 3 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 3 spans almost 200 million base pairs (the building material of DNA) and represents about 6.5 percent of the total DNA in cells The 17q12 recurrent duplication is characterized by intellectual abilities ranging from normal to severe disability and other variable clinical manifestations. Speech delay is common, and most affected individuals have some degree of hypotonia and gross motor delay. Behavioral and psychiatric conditions reported in some affected individuals include autism spectrum disorder, schizophrenia, and. The most common type of chromosomal abnormality is known as aneuploidy, an abnormal chromosome number due to an extra or missing chromosome.Most people with aneuploidy have trisomy (three copies of a chromosome) instead of monosomy (single copy of a chromosome). Down syndrome is probably the most well-known example of a chromosomal aneuploidy

Disorders of chromosome number include the duplication or loss of entire chromosomes, as well as changes in the number of complete sets of chromosomes. They are caused by nondisjunction, which occurs when pairs of homologous chromosomes or sister chromatids fail to separate during meiosis. The risk of nondisjunction increases with the age of. Down syndrome is a well-known example of a numerical disorder (three copies of chromosome 21). A structural abnormality results from alterations in the structure of the chromosome. Structural. Cause: Extra chromosome 18 in each cell (3 copies instead of 2). Trisomy 18 is the second most common trisomy seen in live born individuals. The extra chromosome is likely due to nondisjunction during meiosis. Link: Trisomy 18 Foundation Link: SOFT (Support Organization for Trisomy 18, 13, and Related Disorders) Down Syndrome Other name: Trisomy 2 Numerical abnormalities occur when a person has one or more extra copies of a chromosome (for example, one extra is trisomy, and two extra is tetrasomy) or is missing a chromosome (monosomy). Trisomy can affect any of the 23 paired chromosomes, but the most common are trisomy 21 ( Down syndrome ), trisomy 13 , and trisomy 18 , which affect both. In chromosomal duplications, additional copies of a chromosomal region are formed, which results in different numbers of gene copies within that area of the chromosome. If duplicate sections are adjacent to the original, the process is known as tandem duplication, while if they are separated by unduplicated regions, it is known as displaced.

Duplication in the chromosome can occur in multiple ways; tandem duplication, reverse tandem duplication, displaced duplication, transposed duplication, and extra-chromosomal duplication. Tandem duplication occurs when the duplicated region is present just beside the normal corresponding section of the chromosome A: Numerical Abnormalities. Full Trisomy 16: a chromosomal disorder in which an individual has three copies of chromosome 16 instead of the usual two. Trisomy 16 is not compatible with life and is the most common chromosomal cause of miscarriages (causing over 100,000 miscarriages annually in the U.S. alone)

7q11.23 duplication syndrome is a developmental disorder resulting from an extra copy of ~25 genes on the long arm of chromosome 7. Individuals who have 7q11.23 duplication syndrome have 3 copies of the genes in this region. In contrast, people in the general population have two copies of these genes. 7q11.23 duplication syndrome is sometimes. The duplication of chromosome 3q is a rare disorder with varying chromosomal breakpoints and consequently symptoms. Even rarer is the unbalanced outcome from a parental inv(3) resulting in duplicated 3q and a deletion of 3p. Molecular karyotyping should aid in precisely determining the length and breakpoints of the 3q+/3p− so as to better understand a child's future development and needs Chromosome 8p duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the short arm (p) of chromosome 8. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved Chromosome 5q duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the long arm (q) of chromosome 5. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved

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MECP2 Duplication Syndrome - NORD (National Organization

Duplication of 22q11.2, a segment of chromosome 22, is more than twice as prevalent as a deletion, but carries a similar overall risk of psychiatric conditions. Historically, it was considered that the deletion was much more severe than the duplication, says lead investigator Thomas Werge , head of the Institute of Biological Psychiatry. Chromosome Number Disorders. Of all of the chromosomal disorders, chromosome number abnormalities are the most obviously identifiable from a karyogram. Chromosome number disorders include duplicating or losing entire chromosomes, as well as changes in the number of complete sets of chromosomes Chromosomal abnormality linked to autism disorders. Researchers have fitted another piece into the complex genetic puzzle that is autism, finding DNA deletions and duplications on a specific chromosome that they say explains one to two percent of the 1.5 million cases of autism and related disorders in the United States today

Sex Chromosome Abnormalities - YouTube

Chromosome 22q Duplication Syndrome - DoveMe

That DNA duplication was not found in the DNA of 700 control subjects without clubfoot. They then screened 26 additional patients and found another clubfoot patient with a duplication in chromosome 17 and one more with a deletion, resulting in four patients of 66 screened with defects on chromosome 17 Discussion. Here, we report on 11 patients with duplications at a potential novel disease locus within 19q13.33. Several lines of evidence support the hypothesis that duplications at this locus are associated with NDDs: (1) duplications at this locus are virtually absent in healthy individuals from the general population. 8 Chromosome 17q21.31 duplication syndrome. 613533. 4. TEXT. A number sign (#) is used with this entry because it represents a contiguous gene duplication syndrome. A locus for autism-7 (AUTS7; 610676) has been mapped to chromosome 17q21. See also chromosome 17q21.31 deletion syndrome (610443). Clinical Features. Kirchhoff et al. (2007) reported. An extra copy of a stretch of genes on chromosome 22 may contribute to autism, according to the first study to carefully characterize a large group of individuals who carry this duplication 1. The doubling can also lead to medical complications, such as vision or heart problems. The region, called 22q11.2, is best known for a deletion of the. If a deletion is a missing ingredient in the recipe, a duplication is an extra ingredient. One example of a rare genetic disorder of duplication is called Pallister-Killian syndrome, where part of the #12 chromosome is duplicated

A Polymorphic Genomic Duplication on Human Chromosome 15

Chromosome 18q- Syndrome - NORD (National Organization for

Chromosome Xq27.3-q28 duplication syndrome is an X-linked recessive neurodevelopmental disorder characterized by mild mental retardation, mild facial dysmorphism, short stature, and primary testicular failure manifest as high-pitched voice, sparse body hair, abdominal obesity, and small testes What are chromosome 16 disorders? A: The most common disorder of chromosome 16 is trisomy 16, in which there are three copies of this chromosome instead of the usual pair. Trisomy 16 is responsible for well over 100,000 pregnancy losses a year, representing almost 10% of miscarriages in the US

8q22.1. Leri pleonosteosis chromosome duplication syndrome. 151200. Autosomal dominant. 4. TEXT. A number sign (#) is used with this entry because Leri pleonosteosis is caused by heterozygous microduplication of chromosome 8q22.1 encompassing the GDF6 (601147) and SDC2 (142460) genes. Description A support group for families and individuals seeking support for chromosome 22 disorders. Including 22q11.2 deletion syndrome, Emanuel Syndrome and the 11/22 translocation, 22q11 duplication, ring 22, 22q13 deletion - Phelan-McDermid Syndrome, Cat Eye Syndrome, Schmid-Fraccaro Syndrome, variations of trisomy 22 and unique chormosome 22 conditions Here we present a family with a de novo 1 Mb duplication involving 18 genes on chromosome 19. Within the family there are multiple cases of neurodevelopmental disorders including: Autism Spectrum Disorder, Attention Deficit/Hyperactivity Disorder, Intellectual Disability, and psychiatric disease in individuals carrying this Copy Number Variant. Chromosome Xq28 duplication syndrome. 300815. 4. TEXT. A number sign (#) is used with this entry because this disorder is caused by copy number increase of a small region on distal chromosome Xq28. One report has identified a 0.3-Mb region of Xq28 (chrX:153.2-153.5 Mb, NCBI36) containing at least 11 genes and including the GDI1 gene (300104. MECP2 Duplication Syndrome is a genetic disorder in which there is an extra copy of the MECP2 gene on the X chromosome in each cell, meaning only males are affected. This condition causes severe neurodevelopmental disorders. DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM/ICD-10-CM CODING. Diagnostic testing: The laboratory diagnosis of.

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Affective disorders. Although chromosome 8p showed no evidence of linkage in a genome-wide linkage scan study of schizophrenia and bipolar people, 102, 107 five genome scan studies and one of the. According to Ledbetter's analysis, the 15q duplication is rarely found in controls. There are two types of 15q duplications linked to autism — an interstitial duplication within the chromosome, and an isodicentric form, in which a duplication of the region makes up an extra chromosome Ryan is a very special boy. He has a rare chromosome disorder. A duplication 7q21.13 - to our knowledge, only one other child in the world has this exact sa..