Developmental delay and multiple congenital anomalies in a child with a unique combination of partial monosomy 18 and partial trisomy 16.

A male child with multiple congenital anomalies and developmental delay is described. Cytogenetic evaluation showed that the patient was partially monosomic for the short arm of chromosome 18 and partially trisomic for the short arm of chromosome 16: a combination of chromosomal syndromes not previously described.

Psychosocial impact of predictive testing for Huntington disease on support persons.

Although a support person is required by many centers during the predictive testing protocol for Huntington disease (HD), little is known about the psychosocial impact of predictive testing on persons serving in this role. Eighteen adults who were support persons during predictive HD testing in one HD testing center completed a semi-structured interview to describe their experiences. Participants also completed the Impact of Events Scale (IES) to assess perceptions of emotional distress regarding predictive testing and the State Anxiety Scale of the State Trait Anxiety Inventory (STAI) to assess anxiety regarding the interview. State anxiety scores were similar to normative values for working adults. Although support persons for individuals with a positive gene test scored higher on all measures of the IES than those who were support persons for persons with negative gene mutation results, these differences were not statistically significant. Support persons identified aspects of the protocol that did not fit their needs, perceived the testing process as extending into subsequent caregiving responsibilities when the test was positive, and were uninformed regarding specific caregiving issues for family members with the gene mutation. The impact of the testing experience appeared to be most intense for those support persons who were at-risk offspring of probands. Findings suggest that individual assessment of support person needs may allow more focused counseling of support persons during predictive genetic HD testing. Collaboration with health care providers may facilitate symptom management following testing.

Presymptomatic diagnosis of nonsyndromic hearing loss by genotyping.

BACKGROUND: Nonsyndromic hearing loss (NSHL) is the most common type of hereditary hearing impairment (HHI). It is genetically heterogeneous, and although the exact number of genes is not known, 38 loci have been identified. By cloning the relevant genes and studying the function of the encoded proteins at the molecular level, it may be possible to impact the habitation of persons at risk for HHI. Currently, for select families, presymptomatic diagnosis of NSHL by genotyping is possible. OBJECTIVE: To provide presymptomatic diagnosis of HHI to individuals in select families who have participated in linkage studies. DESIGN: In 2 large families with autosomal dominant HHI, genes for NSHL were mapped to chromosomes 6 (DFNA10) and 19 (DFNA4). In each family, the phenotype is one of progressive sensorineural hearing loss that begins in the individual's mid-30s and progresses to a severe-to-profound loss requiring amplification. Presymptomatic diagnosis was requested by, and provided to, 19 at-risk persons in these kindreds. RESULTS: By reconstructing haplotypes through the use of short tandem repeat polymorphisms tightly linked to the disease gene, risk calculations and genetic counseling were provided to these persons. CONCLUSIONS: By simple Mendelian genetics, the risk of inheriting a fully penetrant autosomal dominant NSHL gene from a single affected parent is 50% for each offspring. However, by reconstructing haplotypes in families in which an HHI gene has been localized, this risk can be changed substantially.

Unique phenotype associated with a pericentric inversion of chromosome 6 in three generations.

We observed a pericentric inversion of chromosome 6 in three generations of one family. Carriers had several phenotypic alterations including congenital cataracts, hearing loss, dental anomalies, ear anomalies, premature graying, unilateral strabismus, coloboma, and mild mental retardation. These manifestations may all be explained by a failure or delay in development of tissues derived from neural crest cells and are similar to these seen in the Rieger syndrome. The description of this family extends the known phenotypic abnormalities associated with alterations of chromosome 6.