Agnathia-holoprosencephaly associated with a 46,XY,-21,+t(21q;21q) karyotype
- Univ. of Illinois, Chicago, IL (United States)
We report an unusual case of agnathia-holoprosencephaly associated with Down syndrome due to a 21/21 translocation. The patient presented prenatally at 21 wks gestation. A fetal ultrasound revealed multiple CNS anomalies including hydrocephalus, compressed cerebellum, absent septum pellucidum and possible cranial meningocele or encephalocele. High resolution ultrasound & fetal karyotype were recommended. The patient refused & elected to have a pregnancy termination. Chromosomal analysis performed on products of conception revealed a 46,XY,-21,+t(21q;21q) karyotype. Fluorescence in situ hybridization was performed and confirmed the 21/21 translocation chromosome. An autopsy revealed agnathia and multiple CNS anomalies including absence of the septum pellucidum, absence of the corpus callosum, arhinencephaly, an occiptal meningoencephalocele, dilation of the lateral ventricles, and extensive dysgenesis & heterotopias of the central cerebrum & mid-brain. Additional abnormalities included a persistent left superior vena cava, atrial & ventricular septal defects, irregular length of the fingers with absence of the middle phalanges of the right 2nd and 5th & left 5th digits and bilateral simian creases. Agnathia can be an isolated abnormality but often is associated with holoprosencephaly and/or situs inversus. The majority of familial case of agnathis-holoprosencephaly was caused by an inherited unbalanced translocation resulting in duplication of 6p and monosomy of 18p. Our patient had a translocation form of trisomy 21 but did not have a phenotype consistent with Down syndrome. Trisomy 21 has not been previously reported in other cases of agnathia-holoprosencephaly. Whether the chromosomal abnormality caused the phenotypic abnormalities or if it is a coincidental finding cannot be determined.
- OSTI ID:
- 133624
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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