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Maternal uniparental disomy for chromosome 14 in a boy with intrauterine growth retardation
O Miyoshi1, S Hayashi, M Fujimoto
1Department of Human Genetics, Nagasaki University School of Medicine, Japan.
Insights
Maternal uniparental disomy for chromosome 14 can cause growth issues. This case reveals a complex rearrangement on chromosome 14, suggesting imprinted genes may cause intrauterine growth retardation.
Area of Science:
- Genetics
- Reproductive Biology
- Developmental Biology
Background:
- Maternal uniparental disomy for chromosome 14 [upd(14)mat] is associated with specific phenotypes, including growth and developmental deficiencies and precocious puberty.
- Intrauterine growth retardation (IUGR) is a significant concern in neonatal development.
Observation:
- A Japanese infant, part of a triplet set, presented with an isochromosome 14 [i(14q)] and IUGR.
- Genetic analysis of the infant's i(14q) and parental alleles revealed a complex inheritance pattern.
Findings:
- The derivative chromosome 14 resulted from a maternal translocation [t(14;14)(p10;q10)] followed by multiple meiotic recombination events.
- Genomic analysis indicated maternal isodisomy in proximal and distal regions of the i(14q), with heterodisomy in an intervening segment.
- These findings suggest the presence of maternally imprinted genes on chromosome 14q.
Implications:
- The loss of a paternally active allele due to upd(14)mat may contribute to IUGR, potentially linked to imprinted gene function.
- Alternatively, IUGR in this context could represent an autosomal recessive trait, with the mother as a heterozygote for a locus on 14q.
Abstract:
Maternal uniparental disomy (UPD) for chromosome 14 [upd(14)mat] may cause a characteristic phenotype with growth and developmental deficiency and precocious puberty. We report the case of a Japanese infant with an isochromosome 14 [i(14q)] and intrauterine growth retardation (IUGR). The infant is one of triplets comprising a boy (the patient) and two karyotypically normal girls. We analyzed parent-child transmission modes of alleles on the i(14q) at 17 CA-repeat marker loci along the entire length of chromosome 14. Genotypes at 4 proximal and 5 distal loci on the i(14q) were consistent with maternal isodisomy, whereas those at an intervening region indicated maternal heterodisomy. Thus, the derivative chromosome 14 had arisen through a translocation between maternal homologous chromosomes 14 [t(14;14)(p10;q10)] after at least two crossing-over events at the first meiosis. This result also suggests that there must be maternally imprinted gene(s) on 14q, and that loss of the functionally active, paternally derived allele in the same locus may lead to IUGR. Alternatively, IUGR may be an autosomal recessive trait. In the latter case, the mother would be a heterozygote and the putative disease locus would be either at the most proximal or most distal region of 14q.