X chromatin and chromosome examination in aged women.

X chromatin frequencies were compared between aged, middle-aged and young women and statistically significant decrease in frequency was found in the aged as compared to the middle-aged and the young women. For a subsample of aged women results of chromosome examinations were also available which allowed comparison of the frequencies of X chromatin and monosomy C; no significant correlation emerged. This latter finding indicates that karyotypic analysis is necessary for the determination of monosomy C; and that X chromatin counts from buccal mucosal cells cannot be substituted for the examination of karyotypes.

Changing phenotype in Floating-Harbor syndrome.

We report on a girl with Floating-Harbor syndrome, trigonocephaly due to metopic suture synostosis, preauricular pit, hypoplastic thumb, subluxated radial head, and Sprengel deformity. A review suggests that trigonocephaly may be an important craniofacial manifestation in this syndrome that is recognizable in infancy. With time, this finding appears to become less noticeable, and the face develops a triangular shape, accentuated by a broad and bulbous nose.

Tetraploidy: a report of three live-born infants.

We present three live-born infants with tetraploidy and compare them with two previously reported live-born infants with the same genetic defect. Common anomalies noted included microcephaly; a prominent, narrow forehead; microphthalmia/anophthalmia; cleft palate; orthopedic anomalies; genital ambiguity; and abnormalities of the central nervous system, including pituitary hypoplasia. Together these constitute a rather characteristic phenotype. An error in cytoplasmic cleavage is theorized to be a mechanism for the chromosome anomaly and is supported by the presence of parental polymorphisms in one of our cases; however, the presence of a small percentage of tetraploid cells in the leukocytes and skin fibroblasts of this patient's mother does not exclude maternal mosaicism as the basis for polyploidy in certain instances.

Gonadal and müllerian duct agenesis in a girl with 46,X,i(Xq).

A unique case of gonadal agenesis and rudimentary müllerian duct development in association with a 46,X,i(Xq) karyotype is reported. The patient presented with short stature and subtle features of Turner syndrome. Endocrine evaluation revealed elevated gonadotropins and cytogenetic findings from both peripheral blood leukocytes and skin fibroblasts were consistent with a 46,X,i(Xq) karyotype. Laparoscopy revealed both uterus and gonads to be absent. Developmental failure of the müllerian system in association with gonadal agenesis in a patient with 46,X,i(Xq) has not been previously reported. The basis for müllerian duct regression in this patient remains unclear. Recommendations for treatment are made.

Dup(4p)del(9p) in a familial mental retardation syndrome. Resemblance to de Lange syndrome detected by high-resolution banding.

A young woman with features resembling de Lange syndrome had a normal banded karyotype. Similar phenotypes were present in a maternal aunt and uncle. Utilizing high-resolution banding, the propositus was found to have a chromosomal abnormality characterized by dup(4p)del(9p). Using the same banding technique, her mother and two of her siblings were identified as having balanced reciprocal translocations. Chromosome studies with high-resolution banding should be performed in these instances even in the presence of a normal banded karyotype. Determining a chromosomal basis for the phenotype may lead to a significant reproductive risk in individuals with balanced chromosomal rearrangements and may afford them with the opportunity to pursue prenatal diagnosis.

De novo 1;10 balanced translocation in an infant with thanatophoric dysplasia: a clue to the locus of the candidate gene.

A female infant with thanatophoric dysplasia was found to have a de novo translocation involving chromosomes 1 and 10. The chromosome abnormality may represent an important clue in identifying the locus for the candidate gene responsible for this lethal skeletal dysplasia.

Greig cephalopolysyndactyly syndrome: altered phenotype of a microdeletion syndrome due to the presence of a cytogenetic abnormality.

A male had several features of Greig cephalopolysyndactyly syndrome (GCPS) and significant developmental delay. He was found to have a de novo chromosomal deletion of chromosome no. 7 involving p13; this resulted in loss of the zinc finger gene, GLI3, which is the candidate gene in this syndrome. Modification of the CGPS phenotype in a sporadic case emphasizes the importance of searching for a chromosomal origin of this autosomal dominant disorder. Detection of a chromosomal deletion in these patients may be associated with a poor prognosis from the standpoint of cognitive development, and the potential for other structural abnormalities not normally associated with GCPS.