Trisomy 8 mosaicism syndrome.

Chromosome 8 is the largest autosome thus far found to be trisomic among liveborn infants. Trisomy 8 "mosaicism" syndrome (T8mS) consists primarily of individuals whose chromosome complement is mosaic for chromosome 8 (T8m), i.e., patients with a chromosomally normal cell line in addition to the trisomic 8 cell line, and a few known individuals with full trisomy 8 (T8), i.e., each cell observed contains an extra chromosome 8. Reported cases of both types share a number of common features and thus have helped to delineate a new syndrome. Common features of T8mS include mild-to-moderate mental retardation, strabismus, osseous and soft tissue abnormalities, lowset and/or malformed ears, broad bulbous nose, palate deformity, various types of congenital cardiovascular disorders, hydronephrosis, cryptorchidism, and characteristic dermatoglyphics. Since chromosomal mosaicism is often present in this syndrome it is not surprising that considerable phenotypic variation exists. The present report of one of the youngest individuals yet described with T8m adds two more physical findings (dense corneal clouding and a heretofore undescribed clavicular deformity) to the constellation of abnormalities associated with T8mS. On the basis of the phenotypic and cytogenetic findings in this and 17 similar patients previously reported it is proposed that T8mS is a distinct clinical entity.

Unusual mosaicism of de novo structural abnormalities and ocular anomalies in a male with 13 trisomy syndrome.

A body with the 13 trisomy syndrome was found to have a unique form of mosaicism in which each of the two cell lines had different structural rearrangements. The predominant cell line was partially trisomic for the distal portion of the long arm of chromosome 13, while the minor cell line was trisomic for all of the long arm of 13. The patient is also unusual because he had congenital glaucoma and was still alive at 10 years.

Ophthalmic features of chromosome deletion 4p- (Wolf-Hirschhorn syndrome).

By using the Giemsa banding technique we identified three patients with chromosome deletion 4p-. All had anterior segment anomalies, exotropia, blepharoptosis, antimongoloid palpebral fissures, hypertelorism, and disk abnormalities. One patient (Case 1) had Rieger's anomaly. Some clinical features in patients with 4p- are similar to those in patients with chromosome deletion 5p-, cri-du-chat syndrome, although 4p- individuals do not have the distinctive cry. The ocular features which distinguish 4p- from other deletions include normal tearing, some degree of blepharoptosis, and the preponderance of anterior segment signs.

Human retinal dysplasia.

We studied the ultrastructure of the four types of dysplastic rosettes and compared them with retinoblastoma rosettes. Dysplastic rosettes have morphologic characteristics intermediate between the normal photoreceptor layer and retino-blastoma rosettes; Müller cells contribute to the formation of dysplastic but not neoplastic rosettes. Abnormality in the relationship between the retina and the retinal pigment epithelium is frequent in cases with spontaneously occurring retinal dsyplasia and is consistent with previous observations that the retinal pigment epithelium influences the development of retinal morphology and function. We believe the normal developmental sequence of cell death and disappearance of necrotic cells may have gone awry in retinal dysplasia.

Unilateral cryptophthalmia.

Two patients had the variable clinical features of unilateral cryptophthalmia. A 5-month-old boy had isolated unilateral cryptophthalmia: a small boney orbit, deformed optic canal, and a small amorphous mass with no normal intraocular tissue representing the globe. No extraocular muscles or optic nerve were identified by B-scan ultrasound or by computed axial tomography x-ray techniques. The second patient, a 13-year-old girl, had unilateral cryptophthalmia, and numerous systemic abnormalities including a head circumference less than the third percentile, severe mental retardation, hypoplasia of the left side of the head, and a left facial cleft deformity. She also had contractures of hips, knees and ankles, and bilateral spasticity and jerky movements. The left boney orbit was contracted and deformed and contained a small amorphous tissue with no ocular detail, as revealed by B-scan and computed tomography scan.

Ocular findings in triploidy.

We studied the abnormal ocular and systemic findings in one case of true triploidy and two cases of triploid mosaicism. A liveborn triploid child 69,XXY, had abnormalities including cebocephaly, a single midline nostril, incomplete cleft palate, transverse palmar creases, partial syndactyly, and ambiguous genitalia. Ocular abnormalities included hypotelorism, blepharophimosis, microcornia, iris coloboma, cataract, persistent hyaloid vasculature, retinal dysplasia, and optic atrophy. A 16-year-old girl with triploid mosaicism had congenital left facial and body hemiatrophy, both growth and mental retardation, left-sided grand mal seizures, incontinentia pigmenti of both legs, partial syndactyly, and generalized weakness. Results of her ocular examination were within normal limits. A 13-year-old boy with triploid mosaicism exhibited both growth and mental retardation, truncal obesity, and required a brace to support his back. Ocular findings included synophrys, bilateral blepharoptosis, and abnormal results of Schirmer tear test. Studies indicate a wide spectrum of ocular and systemic abnormalities occur that are presumably associated with the chromosome error.

Multiple changes in oncogenes and tumor suppressor genes in human retinoblastoma.

PURPOSE: To present data to support the hypothesis that human retinoblastoma tumors form by a multistep process. METHODS: Survey of the karyotype of 90 human retinoblastomas, with emphasis on changes in chromosomal regions known to contain oncogenes and tumor suppressor genes. CONCLUSION: The data support the hypothesis that retinoblastoma occurs after multiple and often varied steps, similar to other human malignancies.

Premature cataracts associated with generalized lentigo.

Generalized lentigo (leopard syndrome) is an autosomal dominant trait characterized by lentigo, sensorineural deafness, retarded growth (below 25%), ocular hypertelorism, mandibular prognathism, pectus carinatum or excavatum, dorsal kyphosis, winging of the scapulae, valvular pulmonary artery stenosis, electrocardiographic conduction defects, and genitourinary defects. Ocular evaluations of patients with generalized lentigo have revealed the appearance of multiple small white punctate and comma-shaped opacities in the cortex and nuclci of the lenses of affected patients. On the basis of age of the patients examined, it would seem that the corneal opacities first appear in the third decade. Although the opacities may be extensive, the lens opacities do not appear to impair visual function until approximately twenty years after they first appear.

Chromosomal abnormalities associated with cyclopia and synophthalmia.

At the present time, essentially all known facts concerning cyclopia are consistent with some chromosomal disease, including clinical features of the pregnancy (fetal wastage, prematurity, intrauterine growth retardation, maternal age factor, complications of pregnancy), the generalized developmental abnormalities, specific ocular dysgenesis, by the high incidence of chromosomal abnormality already demonstrated, and the possibility of error in those cases of cyclopia with normal chromosomes. Even if chromosomal aberrations represent only one group of several different etiologic factors leading to cyclopia, at the present time chromosomal errors would seem to be the most common cause of cyclopia now recognized. Further studies will establish or disprove a chromosomal error in those instances which are now considered to be the result of an environmental factor alone or those with apparent familial patterns of inheritance. This apparent diverse origin of cyclopia can be clarified if future cyclopic specimens are carefully investigated. The evaluation should include a careful gross and microscopic examination of all organs, including the eye, and chromosome banding studies of all organs, including the eye, and chromosome banding studies of at least two cyclopic tissues. Then the presence or absence of multiple causative factors can be better evaluated.