[Muscular hypotonia, developmental retardation, speech delay and mildly dysmorphic features: 22q13 deletion syndrome (Phelan-McDermid Syndrome) as an important differential diagnosis].

BACKGROUND: Clarifying the cause of global developmental and speech delay is of considerable significance in pediatrics. We present the clinical phenotype of the 22q13 deletion syndrome - also known as Phelan-McDermid syndrome - and show the diagnostic options. PATIENT: We report on a female patient with muscular hypotonia, tall stature, minor facial dysmorphism, retarded motor and mental development, and severe speech delay.
METHOD: Chromosomal analysis was performed first on peripheral lymphocytes on GTG-banded chromosomes. Fluorescence in situ hybridization (FISH) analysis was carried out using the dual-color LSI DiGeorge/VCFS Region Probe (TUPLE1, N25) (Vysis/Abbott) and the subtelomeric probe tel 22q13.3 (Tel Vysion 22q).
RESULTS: The analysis of metaphase chromosomes at 450 band resolution showed a normal female karyotype 46,XX. FISH analysis revealed a 22q13 deletion.
CONCLUSION: Muscular hypotonia and developmental delay are non-specific findings observed in many genetic syndromes. In association with severe speech delay and normal or advanced growth pediatricians should consider 22q13 deletion syndrome as a potential cause and initiate a genetic examination.