Mosaic r(13) in an infant with aprosencephaly

Area of Science:

• Genetics
• Developmental Biology
• Clinical Genetics

Background:

• Ring chromosome 13 (r(13)) is a rare chromosomal abnormality associated with various clinical phenotypes.
• The XK-aprosencephaly syndrome is a severe congenital disorder characterized by the absence of the forebrain.

Observation:

• A stillborn male infant presented with a mosaic ring 13 karyotype (45,XY,-13/46,XY,-13,+r(13)).
• The infant displayed apparent aprosencephaly and other brain malformations, including arhinencephaly and cerebellar hypoplasia.
• Clinical findings were notably similar to those previously reported in the XK-aprosencephaly syndrome.

Findings:

• Mosaic ring 13 karyotype in a stillborn male.
• Phenotypic overlap between ring 13 chromosome abnormalities and the XK-aprosencephaly syndrome.
• Presence of aprosencephaly, a rare finding in ring 13 cases, alongside other brain malformations.

Implications:

• Suggests a potential chromosomal mechanism underlying the XK-aprosencephaly syndrome.
• Highlights the phenotypic variability and overlap associated with chromosome 13 abnormalities.
• Informs genetic counseling and diagnostic approaches for congenital brain malformations.