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Longitudinal 12-Month Follow-Up of a Male Infant with CYP21A2 Compound Heterozygous Genotype in China: A Case Report
Yi Yin1, Xinyue Huang1, Yun Shi2
1Department of Prenatal Diagnosis, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
Insights
Early genetic diagnosis and treatment of classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) are crucial. This case highlights effective management through prompt intervention and long-term monitoring for improved outcomes in neonates.
Area of Science:
- Genetics
- Endocrinology
- Pediatrics
Background:
- Congenital adrenal hyperplasia (CAH) is primarily caused by 21-hydroxylase deficiency (21-OHD) due to mutations in the CYP21A2 gene.
- Gene conversion events between CYP21A2 and its pseudogene are a common cause of 21-OHD, leading to impaired enzyme activity.
- Classic CAH presents with significant clinical manifestations requiring timely diagnosis and management.
Observation:
- A male neonate presented with classic CAH symptoms including electrolyte imbalances, hyperpigmentation, and elevated 17-hydroxyprogesterone and ACTH levels.
- Genetic analysis revealed a maternal deletion of CYP21A2 exons 1-7 and paternal compound heterozygous mutations (intronic and exonic).
- Early genetic diagnosis identified 21-OHD, enabling therapeutic intervention within 11 days of birth.
Findings:
- Prompt initiation of treatment with hydrocortisone, fludrocortisone, and sodium chloride effectively managed the patient's condition.
- Long-term monitoring of electrolytes, endocrine function, and physical development confirmed sustained clinical control.
- The case illustrates a clear genotype-phenotype correlation in classic 21-OHD.
Implications:
- This case underscores the importance of comprehensive genetic diagnostics for neonatal 21-OHD.
- Findings contribute to precision medicine approaches for managing rare endocrine disorders in infants.
- Emphasizes the educational value and critical need for early intervention in neonatal 21-OHD care.
Background:
Congenital adrenal hyperplasia (CAH), predominantly caused by 21-hydroxylase deficiency (21-OHD), arises from mutations in CYP21A2 . This frequently occurs via gene conversion events between CYP21A2 and its pseudogene, leading to impaired 21-hydroxylase activity and subsequent CAH manifestations.
Case Description:
We encountered a case of classic CAH, characterized by electrolyte imbalances (hyponatremia: 125.10 mmol/L; hyperkalemia: 7.06 mmol/L), hyperpigmentation, and markedly elevated endocrine marker levels (17-hydroxyprogesterone: 319.91 nmol/L; adrenocorticotropic hormone: 611.00 pg/mL) in a male neonate. Through genetic diagnostics, we identified a maternal-derived deletion of CYP21A2 exons 1-7 combined with paternal-originated compound heterozygous mutations (c.293-13A/C>G in intron 2 and c.332_339 deletion in exon 3). Implementation of early genetic diagnosis revealed 21-OHD, and immediate therapeutic intervention was initiated within 11 days after the birth of the patient. Long-term treatment, including oral hydrocortisone, fludrocortisone, and 0.9% sodium chloride, provided effective clinical control and management, as determined by longitudinal follow-up monitoring of serum electrolyte profiles, endocrine function, and physical development.
Conclusion:
This case provided critical insights into the genotype-phenotype correlations of classic 21-OHD. Our findings will contribute to precision medicine for managing this rare endocrine disorder during critical infancy periods, and emphasize the need for comprehensive genetic diagnostics and educational values for neonatal 21-OHD care.
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