Bilateral polymicrogyria as the indicative feature in a child with a 22q11.2 deletion

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Polymicrogyria (PMG) is a cortical malformation characterized by abnormal brain organization.
• PMG is a heterogeneous disorder, notably associated with 22q11.2 deletion syndrome (velocardiofacial syndrome).
• The association between PMG and 22q11.2 deletion was first identified in 1996, with over 30 cases reported.

Observation:

• In 22q11.2 deletion syndrome, PMG predominantly affects perisylvian areas, often asymmetrically with a right hemisphere predisposition.
• Neurological manifestations include developmental delay, seizures, microcephaly, spasticity, and oromotor dysfunction.
• A case is presented of a seven-month-old boy with microcephaly, short stature, and developmental delay, exhibiting symmetrical perisylvian PMG and a confirmed 22q11.2 deletion.

Findings:

• The patient lacked other common features of velocardiofacial syndrome, highlighting atypical presentations.
• Array-based comparative genomic hybridization confirmed the 22q11.2 deletion.
• PMG, particularly in perisylvian regions, was the primary indicator in this case.

Implications:

• The presence of PMG, especially perisylvian PMG, warrants investigation for 22q11.2 deletion in pediatric patients.
• This finding has significant prognostic value for children diagnosed with 22q11.2 deletion syndrome.
• Clinicians should consider 22q11.2 deletion testing even when typical velocardiofacial syndrome symptoms are absent.