Diagnosis of MECP2 duplication in a child and prenatally

The MECP2 duplication syndrome (Lubs X-linked mental retardation syndrome) is a rare condition with X-linked
inheritance, where affected males are always clinically symptomatic, while female carriers are usually asymptomatic
and only rarely show symptoms of varying severity. The 6-year-old girl was referred for genetic consultation by a
pediatric neurologist because of motor and speech developmental delay. Chromosome analysis revealed a normal
female karyotype. Multiplex ligation-dependent probe amplification (MLPA) analysis with P245 microdeletion syn-
drome 1A probemix detected a heterozygous duplication of the MECP2-4b, MECP2-3 and MECP2-1 probes in the
Xq28 chromosomal region. Fluorescence in situ hybridization (FISH) analysis specific for the Xq28 chromosomal
region did not show duplication. As a result of the family screening, no duplication was detected of the MECP2 gene
in the family except for her mother. The MLPA analysis in the following pregnancy of the affected mother detected
the familial duplication of the MECP2 gene and additionally trisomy 21 in the male fetus. The mother chose the
termination of the pregnancy. Based on the lessons learned from the case we present, in patients with not classified
developmental delay the addition of microdeletion MLPA testing to karyotype analysis using G-band technique may
help establish the genotype-phenotype correlations