Related Experiment Video
Updated: Jun 23, 2026
A Phenotyping Regimen for Genetically Modified Mice Used to Study Genes Implicated in Human Diseases of Aging
Published on: July 14, 2016
Different phenotypy in three siblings with homocystinuria
Figen Varlibas1, Ozlem Cobanoglu, Burcak Ergin
1Haydarpasa Numune Educational and Research Hospital, Neurology, Movement Disorders Department, Kadikoy, Istanbul, Turkey. figenvar@yahoo.com
Insights
Movement disorders in homocystinuria are rare but linked to autoimmune thyroiditis in a severely affected sibling. Further research is needed to explore connections between homocysteine, basal ganglia, immunity, and thyroid disease.
Area of Science:
- Neurology
- Endocrinology
- Genetics
Background:
- Homocystinuria is a rare metabolic disorder.
- Movement disorders are infrequently reported in homocystinuria patients.
- The underlying pathophysiology of these movement disorders remains unclear.
Observation:
- Three siblings with homocystinuria exhibited distinct phenotypes.
- The most affected sibling presented with oromandibular dyskinesia, spasmodic dysphonia, tremor, bradykinesia, generalized dystonia, and elevated thyroid autoantibodies indicating thyroiditis.
- Other siblings displayed marfanoid features and ophthalmic complications, with one showing mild, asymptomatic rigidity.
Findings:
- A strong association was observed between severe movement disorders and autoimmune thyroiditis in the affected sibling.
- Phenotypic variability in homocystinuria was evident, ranging from severe neurological and autoimmune manifestations to milder features.
Implications:
- These findings suggest a potential link between homocysteine metabolism, basal ganglia function, immune system dysregulation, and autoimmune thyroid diseases.
- Further investigation into the interplay of these factors is warranted to elucidate the pathogenesis of movement disorders in homocystinuria.
Introduction:
Movement disorders associated with homocystinuria have been reported as rare cases. Their physiopathology has not yet been clarified.
Methods:
Three siblings in the same family have been described, all with homocystinuria but possessing phenotypic differences.
Result:
The first case presented oromandibular dyskinesia, spasmodic dysphonia, tremor, bradykinesia, and generalized dystonia along with the classic findings of homocystinuria. The second case had marfanoid features and ophthalmic complications of homocystinuria, and also evidence of mild rigidity of which the patient did not complain. The third case had only marfanoid features. The most severely affected family member was the first case who also had increased thyroid peroxidase antibodies, antithyroglobulin antibodies, and thyroiditis.
Conclusion:
The most severely affected sibling presented movement disorders and evidence of autoimmune thyroiditis. These findings have led us to think that research on the relations between movement disorders, basal ganglia, immunity, autoimmune thyroid diseases, and homocysteine should be continued.
Related Concept Videos
01:49Multiple Allele Traits
01:49Multiple Allele Traits
01:35Pedigree Analysis
00:49Complementation Tests
Organisms heterozygous for different mutations are crossed pairwise in all combinations. If present on different genes, the mutations can complement each other by providing the missing...
02:27Trihybrid 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...
01:33Pleiotropy