Evaluation of Patients With Unresolved Chromosome Abnormalities

Launched by NATIONAL HUMAN GENOME RESEARCH INSTITUTE (NHGRI) · Dec 9, 2002

Keywords

ClinConnect Summary

There is a range of genomic aberrations from aneuploidy down to single base pair deletions or inserts. Present technology uses microscopic cytogenetics for detection of large rearrangements (greater than 2 Mb) and molecular techniques for small rearrangements (less than 2 Mb). There is a gap in practical diagnostic technology in that microscopic cytogenetics has poor sensitivity for aberrations less than 5 Mb and the molecular techniques are cumbersome for clinical use in the megabase range. In many cases it is possible to determine that an aberration is present by microscopic cytogenetics ...

Gender

ALL

Eligibility criteria

• • Physical anomalies or developmental anomalies.
• • Karyotype showing derivative chromosome abnormality that is not fully characterized.
• • No abnormal parental karyotype.
• • No prenatal specimens.
• • Probands of all ages, genders, and ethnic origin are eligible.
• • The proband must have a non-mosaic abnormal G-banded chromosome analysis of good quality that shows one or more derivative chromosomes whose foreign component cannot be determined by standard G-banding techniques.
• • The parents should also have G-banded chromosome analysis prior to eligibility for consent 2. If this has not been done by the referring physician, it may be done as part of the protocol.
• • The proband with the abnormal karyotype should have one or more of the following features: dysmorphic features; developmental delay or mental retardation; growth retardation, microephaly, short stature or failure to thrive; behavioral disorder
• • Biological parents must be willing to supply a blood specimen. If they have any of the features listed above, they must attend the clinic if the proband is to be eligible.
• • The proband must be evaluated by the NCHGR clinical genetics service by the PI, a co-investigator, or his associates.
• • Mothers will be queried about potential non-paternity. If non-paternity is possible, the family will need to undergo clinical paternity evaluation before they are enrolled in the study.