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Summary: Partial trisomy 1q (Iq42.13[arrow right]qter) and partial monosomy 6q (6q27[arrow right]qter) in a girl with single median maxillary central incisor, dysgenesis of corpus callosum and developmental delay: A 3-year-old girl presented with mental retardation, developmental delay, seizures, hypotonia, brachycephaly, a triangular face, single median maxillary central incisor (SMMCI), prominent forehead, down-slanting palpebral fissures, hypertelorism, a higharched palate, micrognathia and low-set ears. Computed tomographic scans revealed corpus callosum dysgenesis and hypoplasia of bilateral frontal sinuses. Oligonucleotide-based array comparative genomic hybridization analysis revealed a ~20.7-Mb duplication of lq42.13[arrow right]qter and a ~3.6-Mb deletion of 6q27[arrow right]qter. The karyotype of the girl was 46,XX,der(6)t( 1 ;6)(q42. 13;q27)pat. Mutational analysis of the patient revealed no mutation in the genes o(SHH, SIX3 and TGIF. The present case adds unbalanced chromosome aberration of partial trisomy lq and partial monosomy 6q to the list of genetic conditions associated with SMMCI.
Key-words: Corpus callosum dysgenesis - Monosomy 6q - Single median maxillary central incisor - SMMCI -Trisomy 1q
INTRODUCTION
The 6q27 subtelomeric deletion syndrome is a recognizable syndrome characterized by mental retardation, dysmorphic features, ear anomalies, epicanthic folds, hydrocephalus, abnormal corpus callosum, brain anomalies, seizures, hypotonia, microcephaly and vertebral anomalies (4, 7, 12, 22, 26, 37, 42, 45, 46). Distal partial trisomy lq with a duplication of lq42-»qter has been reported to be associated with a mild phenotype with a triangular face, low-set ears, short stature, psychomotor retardation, cardiac defects, macrocephaly, large fontanelles, prominent forehead, broad flat nasal bridge, high-arched palate and micro/retrognathia (2, 21, 44, 49, 52). Here, we present partial trisomy lq (lq42.13-*qter) and partial monosomy 6q (6q27-»qter) in a girl with single or solitary median maxillary central incisor (SMMCI), corpus callosum dysgenesis and developmental delay. To our knowledge, this is the first report of SMMCI associated with a duplication of lq42-»qter and a 6q27 subtelomeric deletion.
CASE REPORT
The 3-year-old girl was the first child of a 28-year-old mother and a 30year-old father at her birth. She was delivered at 38 weeks of gestation with a body weight of 2,600 g (10-25th centile), a body length of 45 cm (< 3rd centile) and a head circumference of 31 cm (3rd- 10th centile) after an uncomplicated pregnancy. At the age of one year, she was referred to the...