Study of Selected X-Linked Disorders: Aicardi Syndrome

Официальное название

Pathogenesis of Selected X-Linked Dominant Disorders and New Strategies to Identify the Gene Mutated in Aicardi Syndrome

Обзор

Based on our current understanding of Aicardi syndrome, the condition is hypothesized to occur due to a genetic change on the X-chromosome. The research team is investigating Aicardi syndrome to identify the specific gene location associated with the disorder. The investigators are collecting blood and skin biopsy samples from patients and their parents. A permanent cell line is prepared and DNA from the blood and skin samples and cell lines is isolated and then used for genetic testing. The current research includes microarray analysis which which is used to look for duplications or deletions of genetic material, mutation analysis of candidate genes by sequencing, genome-wide sequencing, review of medical records to identify trends suggesting possible candidate genes of interest, and X chromosome inactivation studies.

Подробное описание

Aicardi syndrome is a sporadic X-linked dominant, presumably male-lethal, neurodevelopmental disorder. It was initially characterized by agenesis of the corpus callosum, neuronal migration defects, eye abnormalities (chorioretinal lacunae, colobomas of the optic nerve and microphthalmia) and severe early-onset seizures and neurodevelopmental delay. It is now well recognized that other brain abnormalities, such as polymicrogyria, agyria, cysts and heterotopias are common features of Aicardi syndrome. The investigators previously hypothesized that the gene causing Aicardi syndrome and possibly additional phenotypically similar disorders with X-linked inheritance, such as Goltz syndrome or Focal Dermal Hypoplasia, are in or near the region on chromosome Xp22 that is deleted in another condition named microphthalmia with linear skin defects syndrome (MLS), because all three have some clinical similarities. However, interim studies have shown that this is likely not the case because no mutations were found in Aicardi syndrome in human holocytochrome c-type synthetase (HCCS) , the gene that is deleted or mutated in MLS. In addition, a mouse model for MLS has no features of Aicardi syndrome. Furthermore, the ivnestigators identified mutations in PORCN (Xp11.3) in Goltz syndrome patients, but not in Aicardi syndrome patients. Therefore, it is likely that the mutated gene is elsewhere on the X-chromosome.

For this study the investigators are collecting information on patients with clinical findings suggesting a diagnosis of Aicardi syndrome, MLS syndrome or a condition that phenotypically overlaps with these disorders. A detailed family history will be obtained, when indicated, and additional family members will be evaluated after appropriately obtained written voluntary consent. A detailed report of the history or physical findings will be obtained from referring physicians for patients identified at outside facilities, or the participants may be evaluated by the study collaborators. Blood and skin biopsy will be obtained from affected individuals, unaffected parents and from other affected or unaffected family members where indicated. It is anticipated that some severely affected patients will expire; in that case, (post mortem) pathological specimens may be obtained. Occasionally, affected individuals may undergo surgical procedures with removal of tissues; in this case we may obtain tissues that would be otherwise discarded or that are not essential for further diagnostic studies or clinical care of the patient. It is anticipated that these specimens will be extremely valuable for understanding the pathogenesis of the investigated conditions. DNA, RNA or protein will be prepared from leukocytes and from tissues and used for sequencing and mutation analysis and other molecular studies of the identified genes. Permanent lymphoblastoid cell lines will be prepared and stored in the laboratory as a permanent source of DNA for the molecular studies. Cell lines may be made from skin biopsies

Вмешательства

• Другое Syndrome cause identification

Первичные конечные точки

• Identifying the change in the genetic information that causes Aicardi syndrome [Срок оценки: Through study completion, an average of 20 years]

Критерии участия

Критерии включения

• Features suggestive of Aicardi syndrome (not all features must be present)

• Agenesis of the corpus callosum
• Chorioretinal lacunae
• Seizures (infantile spasms)

Критерии исключения

• none

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Модель наблюдения

Другое

Центры проведения

США · 1 центр

• Baylor College of Medicine — Houston

Публикации

• Aicardi, J, Levebre, J, and Lerique-Koechlin, A (1965) A new syndrome: Spasms in flexion, callosal agenesis, ocular abnormalities. Electroencephalogr Clin Neurophysiol 19, 609-610.
• Donnenfeld AE, Packer RJ, Zackai EH, Chee CM, Sellinger B, Emanuel BS. Clinical, cytogenetic, and pedigree findings in 18 cases of Aicardi syndrome. Am J Med Genet. 1989 Apr;32(4):461-7. doi: 10.1002/ajmg.1320320405. PMID 2773986
• Kitamura K, Yanazawa M, Sugiyama N, Miura H, Iizuka-Kogo A, Kusaka M, Omichi K, Suzuki R, Kato-Fukui Y, Kamiirisa K, Matsuo M, Kamijo S, Kasahara M, Yoshioka H, Ogata T, Fukuda T, Kondo I, Kato M, Dobyns WB, Yokoyama M, Morohashi K. Mutation of ARX causes abnormal development of forebrain and testes in mice and X-linked lissencephaly with abnormal genitalia in humans. Nat Genet. 2002 Nov;32(3):359 PMID 12379852
• Prakash SK, Cormier TA, McCall AE, Garcia JJ, Sierra R, Haupt B, Zoghbi HY, Van Den Veyver IB. Loss of holocytochrome c-type synthetase causes the male lethality of X-linked dominant microphthalmia with linear skin defects (MLS) syndrome. Hum Mol Genet. 2002 Dec 1;11(25):3237-48. doi: 10.1093/hmg/11.25.3237. PMID 12444108
• Schaefer L, Ballabio A, Zoghbi HY. Cloning and characterization of a putative human holocytochrome c-type synthetase gene (HCCS) isolated from the critical region for microphthalmia with linear skin defects (MLS). Genomics. 1996 Jun 1;34(2):166-72. doi: 10.1006/geno.1996.0261. PMID 8661044
• Schaefer L, Prakash S, Zoghbi HY. Cloning and characterization of a novel rho-type GTPase-activating protein gene (ARHGAP6) from the critical region for microphthalmia with linear skin defects. Genomics. 1997 Dec 1;46(2):268-77. doi: 10.1006/geno.1997.5040. PMID 9417914
• Stromme P, Mangelsdorf ME, Scheffer IE, Gecz J. Infantile spasms, dystonia, and other X-linked phenotypes caused by mutations in Aristaless related homeobox gene, ARX. Brain Dev. 2002 Aug;24(5):266-8. doi: 10.1016/s0387-7604(02)00079-7. PMID 12142061
• Van den Veyver IB. Microphthalmia with linear skin defects (MLS), Aicardi, and Goltz syndromes: are they related X-linked dominant male-lethal disorders? Cytogenet Genome Res. 2002;99(1-4):289-96. doi: 10.1159/000071606. PMID 12900577

Идентификаторы

NCT: NCT00697411 · BCM Aicardi H12791

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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