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Maternal origin of extra marker chromosome 1Q31.1-qter and 13pter-q12.12 in a child with dysmorhic features

V B Rao1, L Kerketta, S Korgaonkar

  • 1Institute of Immunohaematology (ICMR) 13th Floor, New multistoryed building, K.E.M. Hospital Campus, Parel, Mumbai-12, India. vbaburao@hotmail.com

Genetic Counseling (Geneva, Switzerland)
|August 9, 2005
PubMed

Insights

A rare genetic condition involving an extra marker chromosome resulted in trisomy 1q and partial trisomy 13q in a child with significant dysmorphic features. This case highlights a maternal translocation as the origin of the extra genetic material.

Area of Science:

  • Genetics
  • Cytogenetics
  • Pediatric Medicine

Background:

  • Extra marker chromosomes can lead to complex genetic disorders.
  • Maternal balanced translocations are a known cause of chromosomal abnormalities in offspring.
  • Trisomy 1q is associated with a distinct set of congenital anomalies.

Observation:

  • A 20-day-old female infant presented with multiple dysmorphic features.
  • Karyotyping revealed an extra marker chromosome.
  • Fluorescence in situ hybridization (FISH) identified the marker as a maternal derivative chromosome 13, containing 1q31.1-qter and 13pter-q12.12 material, originating from a maternal balanced translocation t(1;13)(q31.1;q12.12).

Findings:

  • The child exhibited features consistent with trisomy 1q, including microphthalmia, high arched palate, micrognathia, hypertelorism, low-set ears, and limb contractures.
  • This represents the first reported case of trisomy 1q involving an extra marker chromosome that also includes material from chromosome 13pter-q12.12.

Implications:

  • This case expands the understanding of chromosomal abnormalities arising from maternal translocations.
  • It underscores the importance of detailed cytogenetic analysis, including FISH, for diagnosing complex genetic disorders.
  • Further research may elucidate the specific phenotypic impact of this unique chromosomal rearrangement.

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