Background: Microcephalic osteodysplastic primordial dwarfism (MOPD) is a wide spectrum of monogenic disorders with several subtypes and numerous genes have been identified. It is characterized by the significant pre- and post-natal growth retardation, severe short stature (dwarfism), and microcephaly. MOPD type II (MIM# 210720) is a recessive disease, which is the first mapped MOPD caused by mutations in PCNT (605925) gene encoding pericentrin protein, in chromosome 21q22. In contrast, Klinefelter syndrome (KS; XXY syndrome) is a known numerical chromosomal disorder that is considered the most frequent sex chromosomal with no or minimal physical features before puberty. Affected children may have tall stature and subtle intellectual disabilities, speech delay, and evolving psychosocial dysfunctions.
Case Presentation: We present a 3-year-old dwarf child with the facial and physical finding of MOPD. Interestingly, his karyotype revealed 47;XXY abnormality. While searching for the main cause for his dwarf phenotype, gene testing for PCNT gene showed pathogenic homozygous mutation with both parents proved to be heterozygous for the same mutation.
Conclusion: While the karyotype proved the 47;XXY syndrome, the clinical phenotype of MOPD caused by PCNT leads his physical array and dominated the patient's facial profile. Early diagnosis for both syndromes is essential in order to offer early treatment for the complications or to provide an appropriate counseling and intervention if needed.
Key words: Intrauterine growth retardation; IUGR; primordial dwarfism; MOPD; PCNT; Klinefelter syndrome; developmental delay; 47, XXY.
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