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Case Reports
. 2023 Apr;11(4):e2130.
doi: 10.1002/mgg3.2130. Epub 2023 Jan 24.

3q29 microduplication syndrome: New evidence for the refinement of the critical region

Alessia Bauleo  1 , Vincenza Pace  1 , Alberto Montesanto  2 , Laura De Stefano  1 , Rossella Brando  1 , Domenica Puntorieri  3 , Luca Cento  3 , Maurizio Genuardi  4   5 , Elena Falcone  1
Affiliations
Case Reports

3q29 microduplication syndrome: New evidence for the refinement of the critical region

Alessia Bauleo et al. Mol Genet Genomic Med. 2023 Apr.

Abstract

Background: The 3q29 microduplication syndrome is a rare genomic disorder characterized by an extremely variable neurodevelopmental phenotype usually involving a genomic region ranging from 1.6 to 1.76 Mb. A small microduplication of 448.8 Kb containing only two genes was recently described in a patient with a 3q29 microduplication that was proposed as the minimal critical region of overlap of this syndrome.

Methods: Molecular karyotyping (array-CGH) was performed on DNA extracted from peripheral blood samples using Agilent-California USA Human Genome CGH Microarray 4 × 180 K. The proband and his younger brother were further tested with a next generation sequencing (NGS) panel including genes implicated in autism spectrum disorder and in neurodevelopmental disorders. Quantitative real-time PCR was applied to verify the abnormal array-CGH findings.

Results: Here, we report on a family with two males with neurodevelopmental disorders and an unaffected sibling with a small 3q29 microduplication (432.8 Kb) inherited from an unaffected mother that involves only two genes: DGL1 and BDH1. The proband had an additional intragenic duplication inherited from the unaffected father. Further testing was negative for Fragile X syndrome and for genes implicated in autism spectrum disorder and in neurodevelopmental disorders.

Conclusion: To the best of our knowledge, one of the family members here analyzed is the second reported case of a patient carrying a small 3q29 microduplication including only DGL1 and BDH1 genes and without any additional genetic aberration. The recognition of the clinical spectrum in patients with the critical region of overlap associated with the 3q29 duplication syndrome should prove valuable for predicting outcomes and providing more informed genetic counseling to patients with duplications in this region.

Keywords: 3q29 microduplication; CNV; array-CGH; minimal critical region; neurodevelopmental phenotypes.

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Conflict of interest statement

The authors have no conflicts of interest to declare.

Figures

FIGURE 1
FIGURE 1
Family tree with affected proband (II‐2) and his younger brother (II‐3) indicated in black. Open symbols indicate unaffected individuals who do not carry the 3q29 microduplication. Individuals II‐1 (proband's sister) and I‐1 (proband's mother) are indicated in gray since they carry the same microduplication but do not express the phenotype
See this image and copyright information in PMC

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