A 28-year-old woman delivers an infant with hypotonia, upslanting palpebral fissures, and a single palmar crease. Vital signs show HR 120/min, RR 28/min, and mild hypothermia at 36.2°C. Serum TSH is normal, excluding congenital hypothyroidism. Karyotype reveals 46 chromosomes with translocation of chromosome 21 material onto chromosome 14. The mother's karyotype is normal. Which of the following best describes this chromosomal abnormality?
- A)Mitochondrial heteroplasmy
- B)Balanced Robertsonian translocation in a parent with unbalanced segregation in the childGABARITO
- C)Triplet repeat expansion
- D)Isochromosome formation
- E)Somatic mosaicism
Explicação
A Robertsonian translocation involves fusion of the long arms of two acrocentric chromosomes, commonly 14 and 21. A balanced carrier parent can be phenotypically normal but produce offspring with translocation Down syndrome because of unbalanced segregation at... Ver explicação completa e trilha adaptativa →