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Published on: April 26, 2019

Achondroplasia-hypochondroplasia complex in a newborn infant

M J Huggins1, J R Smith, K Chun

  • 1Department of Laboratory Medicine, Hamilton Health Sciences Corporation, Ontario, Canada. hugginsm@exchange1.cmh.on.ca

American Journal of Medical Genetics
|June 9, 1999
PubMed

Insights

This case study details an 8-month-old girl with achondroplasia-hypochondroplasia complex, a rare genetic disorder. Molecular testing confirmed compound heterozygous mutations in the fibroblast growth factor receptor 3 (FGFR3) gene.

Area of Science:

  • Genetics
  • Pediatrics
  • Skeletal Dysplasias

Background:

  • Achondroplasia and hypochondroplasia are skeletal dysplasias caused by mutations in the fibroblast growth factor receptor 3 (FGFR3) gene.
  • Genetic counseling and molecular testing are crucial for diagnosing skeletal dysplasias during pregnancy.
  • This report focuses on a rare complex form of skeletal dysplasia.

Observation:

  • Antenatal ultrasonography revealed severe fetal anomalies including short limbs, macrocephaly, and a small chest.
  • The patient presented with rhizomelic limb shortening, large head, small chest, and mild lung hypoplasia postnatally.
  • Clinical examination at 8 months showed disproportionate limb shortening, frontal bossing, depressed nasal bridge, and motor development delay.

Findings:

  • Molecular testing confirmed compound heterozygous mutations in FGFR3: G1138A (achondroplasia) and C1620G (hypochondroplasia).
  • Radiographs demonstrated characteristic features of achondroplasia, including shortened long bones and metaphyseal flaring.
  • The patient exhibits features consistent with achondroplasia-hypochondroplasia complex, a condition with limited prior documentation.

Implications:

  • This case highlights the importance of genetic testing for FGFR3 mutations in suspected skeletal dysplasias.
  • Understanding the genetic basis of achondroplasia-hypochondroplasia complex can aid in prenatal diagnosis and management.
  • Further research is needed to elucidate the long-term prognosis and management strategies for this rare condition.

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