Ocular pathology in trisomy 18. A histopathological report of three cases

Ophthalmic histopathology is presented in three cases of trisomy 18. The children, who showed typical systemic anomalies, died in the first few days of life. In two cases the cornea was normal, while in one case hypercellularity of the stroma was found and Bowman's and Descemet's layers were absent. A minimal cataract was also present in two cases. Retinal folds were a common finding in the posterior region in all three cases. In one case, a partial coloboma of the optic disc was present in both eyes. In case 2, a pouch between the optic nerve and the dural sheath was considered to be a minimal developmental disturbance of the primitive epithelial papilla possibly representing an optic pit. The absence of pigment epithelium on the nasal disc border in case 3, also points to a deformity of the primitive papilla. The importance of the disc region in clinical and histopathological investigation is stressed.

[Renal agenesis and the Fraser syndrome: 4 observations]

The authors report on 4 cases of Fraser syndrome in 2 Turkish families. Both families are consanguinous. In 3 cases there is a bilateral renal agenesis, a feature which is not usually regarded as a main one. Actually the survey of the literature reveals that renal anomalies are not infrequent in this syndrome, even though the cryptophtalmos would be lacking. A five year study of the malformations Registry of the Rhone-Alpes-Auvergne-Jura area shows that the association between renal agenesis and syndactyly (with or without the eye abnormalities) is quite rare. Such an association leads to the diagnosis of Fraser Syndrome even when cryptophtalmos is absent, and requires to look for minor ENT or ophthalmic symptoms by a careful post mortem examination.

Case of cyclopia with an unbalanced karyotype attributable to a balanced 3/7 translocation

This report presents a case of cyclopia attributable to an unbalanced karyotype in a family with a balanced, reciprocal 3/7 translocation. This case was the fifth recorded in three generations of this family. From this report it is possible that the simultaneous action of partial trisomy 3p and partial monosomy 7q may be one cause of holoprosencephaly.

[The Hallermann-Streiff syndrome in 2 generations]

The authors discuss a rare case, unique in our literature, of the familial incidence of Hallermann-Streiff's syndrome and the treatment of some of its complications. Special emphasis is laid on genetic analysis which provides evidence of autosomal dominant heredity with a variable expressivity of the pathological gene, and which must be applied in genetic consultations.

Histochemical analysis of extracellular matrix material in embryonic trisomy 1 mouse eye

Trisomic animals produced from mice doubly heterozygous for Robertsonian translocation chromosomes [Rb(1.3)/Rb(1.10)]consistently show eye defects (e.g., aphakia, microphakia, and retention of lens stalk). To determine if changes in distribution or composition of extracellular matrix material may be a factor in development of these defects, eye structures of trisomy (ts) 1 embryos and normal littermates were studied histochemically using the following methods: Alcian blue 8GX, pH 2.5; periodic acid-Schiff (PAS), Alcian blue/PAS combined; high-iron diamine (HID), and HID/Alcian blue combined. Eye development was divided into stages to account for the known delay in ts 1 mouse development. Differences were found in staining patterns as early as stage 1. In later stages, the most consistent difference was an increased period of contact between lens and optic cup due to retardation of interface matrix dissolution between these rudiments in ts 1 embryos. Eyes in which this occurred had abnormally shaped lenses. Overall, the ts 1 optic cup appeared to have fewer staining abnormalities and dysmorphology than did the lens or interface matrix. Triplication of a chromosome may indirectly alter temporal and spatial organization of extracellular matrix through action on cells responsible for the production of this material. Possible mechanisms of action are discussed.

Short-limbed dwarfism and ocular defects in the Samoyed dog

A syndrome of short-limbed dwarfism and ocular defects was found in Samoyed dogs. The most prominent abnormalities were small stature and valgus deformity of the carpi. Radiographic evidence of retarded growth at the distal ulnar physis was apparent by 12 weeks of age. Ocular defects included cataracts and retinal detachment. Family studies and limited breeding experiments were consistent with an autosomal recessive mode of inheritance.

Development of Dickie's small eye, a mutation in the house mouse

A new semidominant mutation in the laboratory mouse, Dickie's small eye (Dey), is described. It is localized on chromosome 2. Heterozygotes show reduced body size, small eyes with coloboma, small or lacking lens with cataract, abnormal folding of the retina and reduction of the pigment layer. The anterior chamber is usually missing. Homozygotes apparently die early in pregnancy.