Double trisomy (XXX+21 karyotype) in a six-year-old girl with down phenotype

Area of Science:

• Genetics
• Developmental Pediatrics
• Clinical Case Study

Background:

• Down syndrome (Trisomy 21) is a common genetic disorder associated with developmental delays.
• Triple X syndrome (Trisomy XXX) is a chromosomal condition affecting females.
• Double trisomy, such as XXX,+21, is exceptionally rare with limited documented cases.

Purpose of the Study:

• To report a rare case of a child with a double trisomy (47, XXX, +21).
• To describe the clinical presentation and developmental profile of a child with this rare genetic anomaly.
• To highlight the specific developmental challenges, particularly in language, observed in this condition.

Main Methods:

• Case report of a six-year-old female patient.
• Clinical examination for dysmorphic features.
• Developmental assessment to evaluate cognitive and language skills.
• Review of previous karyotype studies confirming the genetic anomaly (47, XXX, +21).

Main Results:

• The patient presented with dysmorphic features consistent with Down syndrome.
• Significant global developmental delay was noted, with a developmental age of 32 months.
• Severe language delay was evident, with limited expressive vocabulary and reliance on non-verbal communication.
• Auditory responses were normal despite communication difficulties.

Conclusions:

• This case represents a rare instance of double trisomy (47, XXX, +21) with significant developmental and language impairments.
• The findings underscore the variability in developmental outcomes for rare chromosomal abnormalities.
• Further research is needed to understand the specific developmental trajectories and management strategies for children with this double trisomy condition.