Obstet Gynecol Sci.  2014 Jul;57(4):318-324. 10.5468/ogs.2014.57.4.318.

Prenatal diagnosis of a 7q21.13q22.1 deletion detected using high-resolution microarray

Affiliations
  • 1Department of Laboratory Medicine, Keimyung University School of Medicine, Deagu, Korea.
  • 2Department of Obstetrics and Gynecology, Keimyung University School of Medicine, Deagu, Korea. gonmd@dsmc.or.kr
  • 3Department of Pediatrics, Keimyung University School of Medicine, Deagu, Korea.

Abstract

We report a case of de novo 7q interstitial deletion detected by conventional karyotyping and by microarray of amniotic fluid sampled during the prenatal period. A 32-year-old pregnant woman was evaluated at our hospital following detection of increased nuchal translucency at 12 weeks and 5 days of gestation. Conventional karyotyping revealed 46,XX,del(7)(q21q22) in 20 interphase mitotic cells, and high-resolution microarray revealed 12.8 Mb (90,625,014-103,430,901) deletion in the region 7q21.13q22.1. Both parents had normal karyotypes. After birth, the neonate displayed several anomalies, including palatine cleft, upslanted and wide palpebral fissure, low-set ears, micrognathia, microcephaly, ventriculomegaly, subglottic tracheal stenosis, hearing loss, and hand/foot deformities, including brachydactyly, polydactyly, and cutaneous syndactyly. This case study helps explain the phenotype-genotype relationship in patients with 7q21.13q22.1 deletion.

Keyword

7q deletion; 7q21.13; 7q22.1

MeSH Terms

Adult
Amniotic Fluid
Brachydactyly
Congenital Abnormalities
Ear
Female
Hearing Loss
Humans
Infant, Newborn
Interphase
Karyotype
Karyotyping
Microcephaly
Nuchal Translucency Measurement
Parents
Parturition
Polydactyly
Pregnancy
Pregnant Women
Prenatal Diagnosis*
Syndactyly
Tracheal Stenosis

Figure

  • Fig. 1 (A) Karyogram obtained prenatally from sampled amniotic fluid. Intermediate deletion of chromosome 7 between bands 21 and 22 was observed (arrow indicates the deleted segment). (B) The microarray result of the patient. The result showed a log reduction and loss of heterozygosity at the 7q21.13q22.1 region, which had a maximal size of 12.8 Mb from 90.63 to 103.43 Mb of chromosome 7. (C) Polydactyly between the second and third toes of the infant's left foot. Cutaneous syndactyly of the first and second toes; retroflexed first and fifth toes are observed. (D) Overview of the chromosome 7q21-q22 region, showing genes related to the clinical phenotype of 7q21q22 deletion. Different phenotype results among previous cases and ours suggest the existence of other factors, besides DLX5, DLX6, and DSS1, affecting the expression of split hand or foot. And the unique chromosomal region deleted in our patient, which does not fully overlap with deletions harbored by other cases, will be applicable to functional studies of the 7q22.1 region [3,4,5,6].


Reference

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