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De novo deletion (14)(q11.2q13) including PAX9: clinical and molecular findings
S Schuffenhauer1, H J Leifheit, P Lichtner
1Department of Medical Genetics, Children's Hospital, Ludwig-Maximilians-University Munich, Germany.
Insights
A rare genetic deletion on chromosome 14 (14)(q11.2q13) in a child led to severe developmental issues. This case is the first to report PAX9 hemizygosity, potentially explaining the observed congenital anomalies and swallowing difficulties.
Area of Science:
- Human Genetics
- Developmental Biology
- Clinical Medicine
Background:
- De novo deletions in humans can lead to complex congenital anomalies.
- Understanding the genetic basis of developmental disorders is crucial for diagnosis and treatment.
- The PAX9 gene plays a role in embryonic development, but its role in human congenital disorders is not fully understood.
Observation:
- A 3-year-old boy presented with a de novo deletion on chromosome 14 (14)(q11.2q13).
- The deletion encompassed the region from D14S264 to D14S70.
- Clinical manifestations included severe psychomotor retardation, cleft lip/palate, optic nerve and retinal colobomas, agenesis of the corpus callosum, pes calcaneovarus, reduced esophageal peristalsis, and dysphagia.
Findings:
- This is the first reported case of PAX9 hemizygosity in humans.
- The deletion interval was analyzed, and the bZIP transcription factor gene NRL was excluded.
- The findings suggest PAX9 hemizygosity as a potential cause for the observed developmental defects and dysphagia.
Implications:
- This case highlights the significance of PAX9 gene haploinsufficiency in human development.
- Further research into PAX9 function could elucidate mechanisms underlying similar congenital disorders.
- The study contributes to the understanding of genotype-phenotype correlations in chromosomal deletion syndromes.
Abstract:
A 3 year old boy with a de novo deletion (14)(q11.2q13) of paternal origin encompassing the region from D14S264 to D14S70 is described. The patient presented with severe psychomotor retardation, bilateral cleft lip/palate, bilateral colobomas of the optic nerves and retinas, agenesis of the corpus callosum, pes calcaneovarus, reduced oesophageal peristalsis, and swallowing difficulties. This is the first reported case of PAX9 hemizygosity in humans. Haploinsufficiency of the PAX9 gene might be expected to cause some of the developmental defects and the dysphagia. Another haploinsufficiency candidate gene, the bZIP transcription factor gene NRL, which is specifically expressed in neuronal cells and the eye during embryogenesis, was excluded from the deletion interval.