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Meiosis I

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Meiosis is a carefully orchestrated set of cell divisions, the goal of which—in humans—is to produce haploid sperm or eggs, each containing half the number of chromosomes present in somatic cells elsewhere in the body. Meiosis I is the first such division, and involves several key steps, among them: condensation of replicated chromosomes in diploid cells; the pairing of homologous chromosomes and their exchange of information; and finally, the separation of homologous chromosomes by a...

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Nondisjunction

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Related Experiment Video

Updated: Jun 29, 2026

A Novel Strategy Combining Array-CGH, Whole-exome Sequencing and In Utero Electroporation in Rodents to Identify Causative Genes for Brain Malformations

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Multiple ocular abnormalities associated with trisomy 4p.

Samin Hong¹, Sung Yong Kang, Gong Je Seong

¹Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

Ophthalmic Surgery, Lasers & Imaging : the Official Journal of the International Society for Imaging in the Eye

|October 4, 2008

Summary

Trisomy 4p is rarely associated with ocular issues, but this case shows bilateral cataracts and other abnormalities. Surgical intervention improved vision, highlighting the need for ophthalmic exams in such patients.

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Area of Science:

Ophthalmology
Genetics
Medical Science

Background:

Trisomy 4p, a rare chromosomal abnormality, is infrequently associated with ocular manifestations.
Previous literature has rarely detailed the specific ocular features linked to trisomy 4p.

Observation:

The authors observed multiple ocular abnormalities in a patient with trisomy 4p, including bilateral cataracts, posterior synechiae, and posterior segment changes.
These intraocular findings were presumed to be secondary to a prior inflammatory process.

Findings:

Surgical removal of bilateral cataracts and subsequent intraocular lens implantation led to the recovery of useful vision in the affected patient.
This case demonstrates a potential treatment pathway for visual impairment in trisomy 4p.

Implications:

A comprehensive ophthalmic examination is recommended for all patients diagnosed with trisomy 4p.
Early detection and management of ocular abnormalities may improve visual outcomes in individuals with autosomal imbalances.