Maternal and fetal tyrosinemia type I

Area of Science:

• Medical Genetics
• Metabolic Disorders
• Prenatal Care

Background:

• Tyrosinemia type I (HT1) is a rare genetic disorder affecting amino acid metabolism.
• Maternal HT1 requires careful management during pregnancy to mitigate risks to the fetus.
• Genetic counseling is crucial for consanguineous couples with a history of HT1.

Observation:

• A 22-year-old woman with HT1, homozygous for an FAH mutation, conceived with her heterozygous first cousin.
• During pregnancy, the mother was managed with a low-tyrosine diet and nitisinone, maintaining specific plasma levels.
• The infant was born clinically healthy, with normal initial biochemical markers, despite being affected with HT1.

Findings:

• The neonate presented with hypertyrosinemia and detectable nitisinone levels at birth.
• Despite initial normal urinary markers, succinylacetone became detectable by day 15, confirming HT1.
• Molecular confirmation of HT1 in the infant prompted the initiation of specific treatment.

Implications:

• This case highlights the potential for successful pregnancy outcomes in mothers with HT1 under appropriate management.
• Early detection and prompt treatment initiation in infants with HT1 are critical for preventing severe complications.
• Consanguinity increases the risk of recessive genetic disorders like HT1, underscoring the importance of genetic screening.