Mirror-image trigger thumb in dichorionic identical twins.
Eric D Wang1, Xiaoti Xu, Alexander B Dagum
1Division of Hand Surgery, Department of Orthopaedic Surgery, Stony Brook University Medical Center, Stony Brook, New York 11794, USA. eric.wang@hsc.stonybrook.edu
Orthopedics
|June 14, 2012
Summary
This study details identical twins with unilateral trigger thumbs presenting asynchronously. Findings suggest a multifactorial etiology for pediatric trigger thumb, involving both genetic and acquired factors.
Area of Science:
- Pediatric Orthopedics
- Developmental Biology
- Genetics
Background:
- Pediatric trigger thumb, a condition caused by flexor pollicis longus tendon and A1 pulley mismatch, has a debated congenital versus acquired etiology.
- Previous reports of familial and twin associations suggested a congenital cause, though cases diagnosed at birth are rare.
Observation:
- This report describes the first case of dichorionic, monozygotic identical twins with unilateral trigger thumbs affecting contralateral hands.
- The twins presented asynchronously at 11 and 18 months, contradicting a solely congenital cause and current understanding of laterality determination.
Findings:
- The asynchronous and mirror-image presentation in identical twins challenges a purely congenital etiology for pediatric trigger thumb.
- This unique case supports a multifactorial model involving both genetic predisposition and acquired influences.
Implications:
- Understanding the multifactorial etiology is crucial for accurate diagnosis and management of pediatric trigger thumb.
- Further research into genetic and environmental factors can elucidate the complex developmental pathways of this condition.
Related Concept Videos
01:34Crossing Over
Unlike mitosis, meiosis aims for genetic diversity in its creation of haploid gametes. Dividing germ cells first begin this process in prophase I, where each chromosome—replicated in S phase—is now composed of two sister chromatids (identical copies) joined centrally.
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
01:30Crossing Over
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I, duplicated...
01:49Meiosis I
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...
02:05Chromosome Duplication
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
02:27Trihybrid Crosses
Trihybrid Crosses
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...
01:29Nondisjunction
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.