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Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea, Department of Rehabilitation Medicine1, College of Medicine, The Catholic University of Korea, Seoul, Korea , Department of Laboratory Medicine2 |
Background/Objectives
Xq28 duplication syndrome is known to result in intellectual disability, and those with MECP2 gene duplication is the most common type. Distal Xq28 duplication, also known as Int22h1/Int22h2 mediated Xq28 duplication, is another type of Xq28 duplication syndrome and is associated with RAB39B gene. Recently, there have been reports on K/L-mediated Xq28 duplication, where duplication is confined in the middle of these two regions. K/L-mediated Xq28 duplication is associated with duplication of low-copy repeats between K1/K2 and L1/L2, not encompassing MECP2 and RAB39B gene. MRI findings of these K/L-mediated Xq28 duplication have been introduced in previous papers. However, diffusion tensor tractography (DTT) findings, which is useful in describing white matter tracts and which often show abnormalities even in normal brain magnetic resonance imaging (MRI) findings, have not been reported yet. Here, we review DTT findings of the child with K/L-mediated Xq28 duplication.
Case Report
8-month year old male child visited department of rehabilitation medicine with developmental delay. He was born at 40-week gestational age by cesarean delivery, and was treated with neonatal pneumonia. On physical examination, he did not show any dysmorphic features, but showed severe truncal hypotonia.
Genetic counseling was done, and chromosome analysis revealed 46, XY at the 550 band level. An array comparative genomic hybridization (CGH) revealed Xq28 (153576890-153822717) duplication. The array CGH of the patient’s mother also revealed Xq28 duplication. The duplication was estimated to be 246Kb in size and it contained FLNA, GDI1, and RPL10 genes. Unlike the patient, the mother did not show any abnormal features.
Further evaluation with brain MRI with DTT was done at 13-month year old. Brain MRI showed no definite abnormalities except thinning of corpus callosum with chronic periventricular leukomalacia. However, DTT showed not only corpus callosum abnormality, but also showed reduced white matter tract volume in corticospinal tract, uncinate fasciculus, and cingulum. There was no reconstruction of inferior fronto-occipital fasciculus and arcuate fasciculus (Figure 1).
Early intervention with physical therapy was done. Recently, spasticity at both lower extremities and subtle ankle clonus are seen. Follow up BSID-III done at the age of 14-month revealed cognition, receptive-communication, expressive-communication, fine motor, and gross motor with 10, 7, 8, 9, and 8 months respectively.
Conclusion
We report here brain neural tracts of the patient with K/L-mediated Xq28 duplication. By using array CGH and DTT together, it would be useful to explain the clinical findings of the patient. Future studies with DTT findings of more patients with Xq28 duplication may help setting programs in rehabilitation progress.
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