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Published on: August 15, 2019
[Analysis of clinical features and genetic variant in a child with Cowden syndrome 1]
Lulu Yan1, Liyun Tian, Yuxin Zhang
1Ningbo Women and Children's Hospital, the Central Laboratory of Birth Defects Prevention and Control, Ningbo, Zhejiang 315012, China. lihaibo_775@163.com.
Insights
Genetic testing identified a PTEN gene variant (c.781C>T) in a child and his mother, confirming the cause of Cowden syndrome 1 (CS1) and aiding family genetic counseling.
Area of Science:
- Genetics
- Molecular Biology
- Clinical Genetics
Background:
- Cowden syndrome 1 (CS1) is a rare genetic disorder characterized by an increased risk of developing benign and malignant tumors.
- The PTEN gene is frequently implicated in CS1, playing a crucial role in cell growth and tumor suppression.
Observation:
- A 13-year-old boy presented with severe intellectual disability, autistic behavior, macrocephaly, and characteristic skin findings.
- His mother exhibited multiple papules, hamartomatous polyps, thyroid adenoma, and macrocephaly, suggesting a potential genetic link.
Findings:
- Whole exome sequencing (WES) revealed a likely pathogenic nonsense variant (c.781C>T, p.Q261*) in the PTEN gene in both the child and his mother.
- Sanger sequencing confirmed the inheritance of this PTEN variant from the mother to the child.
Implications:
- The identified PTEN variant (c.781C>T) is likely the underlying cause of Cowden syndrome 1 in this family.
- This genetic finding is crucial for accurate diagnosis, risk assessment, and personalized genetic counseling for affected family members.
Objective:
To explore the genetic etiology of a child with Cowden syndrome 1 (CS1).
Methods:
A child who had visited the Ningbo Women and Children's Hospital on August 26, 2022 was selected as the study subject. Clinical information of the child was collected. Genomic DNA was extracted from peripheral blood samples of the child and his family members and subjected to whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing.
Results:
The child, a 13-year-old boy, had manifested with severe mental retardation, hyperactivity, autistic behavior, sparse and prominent teeth, macrocephaly, and skin freckles on the penis. His mother had presented with multiple papules, hamartomatous polyps, thyroid adenoma and macrocephaly. WES results revealed that the child has harbored a nonsense c.781C>T (p.Q261*) variant of the PTEN gene, which was inherited from his mother. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.781C>T variant was classified as likely pathogenic (PVS1+PM2_Supporting).
Conclusion:
The c.781C>T variant of the PTEN gene probably underlay the pathogenesis in the child and his mother. Above finding has facilitated genetic counseling for this family.
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