Biomedical subjects

Lisa G Shaffer

Publications and source records attributed to Lisa G Shaffer.

58 records · Page 4Linked to original sources

PubMed2002

The importance of investigating for uniparental disomy in prenatally identified balanced acrocentric rearrangements.

We report the finding of paternal isodisomy for chromosome 14 in a fetus found to have a der(14;14)(q10;q10) by amniocentesis. The pregnancy was complicated by severe polyhydramnios and elevated amniotic fluid alpha-fetoprotein (AFP). The infant showed features consistent with paternal uniparental disomy (UPD) including postnatal growth retardation, poor respiratory function, feeding difficulties, and evidence of hypertrophic cardiomyopathy. The present case, in addition to other reported cases of UPD involving balanced acrocentric rearrangements, supports testing for UPD in prenatally detected Robertsonian translocations and isochromosomes.

Adult↗

PubMed2001

Loss of the SKI proto-oncogene in individuals affected with 1p36 deletion syndrome is predicted by strain-dependent defects in Ski-/- mice.

Experiments involving overexpression of Ski have suggested that this gene is involved in neural tube development and muscle differentiation. In agreement with these findings, Ski-/- mice display a cranial neural tube defect that results in exencephaly and a marked reduction in skeletal muscle mass. Here we show that the penetrance and expressivity of the phenotype changes when the null mutation is backcrossed into the C57BL6/J background, with the principal change involving a switch from a neural tube defect to midline facial clefting. Other defects, including depressed nasal bridge, eye abnormalities, skeletal muscle defects and digit abnormalities, show increased penetrance in the C57BL6/J background. These phenotypes are interesting because they resemble some of the features observed in individuals diagnosed with 1p36 deletion syndrome, a disorder caused by monosomy of the short arm of human chromosome 1p (refs. 6-9). These similarities prompted us to re-examine the chromosomal location of human SKI and to determine whether SKI is included in the deletions of 1p36. We found that human SKI is located at distal 1p36.3 and is deleted in all of the individuals tested so far who have this syndrome. Thus, SKI may contribute to some of the phenotypes common in 1p36 deletion syndrome, and particularly to facial clefting.

Abnormalities, Multiple↗

PubMedDate not supplied

A cytogeneticist's perspective on genomic microarrays.

The identification of cytogenetic imbalance is an important component of clinical genetics. About 1 in 154 newborns has a chromosome abnormality. Conventional cytogenetic analysis has enabled the identification of microscopic alterations of the chromosomes. The development of fluorescence in situ hybridization (FISH) and other molecular methodologies has made possible the identification of submicroscopic aberrations. An additional development was comparative genomic hybridization (CGH), a method that directly compares two genomes for DNA copy differences. As first developed, the substrate for CGH analysis is normal metaphase chromosomes. Recently, CGH has been applied to microarrays (array CGH) constructed from large insert clones to identify chromosome imbalance. Array CGH has many advantages over conventional cytogenetic and molecular cytogenetic techniques. Array CGH can be comprehensive (genome-wide), high resolution, amenable to automation, rapid, and sensitive. We anticipate that array CGH will be employed in the clinical cytogenetics laboratory in the near future and will lead to the identification of the chromosomal basis of new syndromes and existing genetic conditions.

Chromosome Aberrations↗

PubMedDate not supplied

American College of Medical Genetics guideline on the cytogenetic evaluation of the individual with developmental delay or mental retardation.

DISCLAIMER: This guideline is designed primarily as an educational resource for medical geneticists and other health care providers to help them provide quality medical genetic services. Adherence to this guideline does not necessarily assure a successful medical outcome. This guideline should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the geneticist should apply his or her own professional judgment to the specific clinical circumstances presented by the individual patient or specimen. It may be prudent, however, to document in the patient's record the rationale for any significant deviation from this guideline.

Child↗