ABSTRACT
The 16q21 --> qter duplication is a chromosomal abnormality rarely found in liveborn infants, with only four published cases. We report here on the 7-year follow-up of a female patient with trisomy 16q21 --> qter due to a maternal balanced translocation t(4;16)(q35.2;q21). The patient shows severe mental retardation, congenital heart malformations, nephropathy, and other congenital anomalies. The derivative chromosome was characterized by GTG banding, fluorescent in situ hybridization (FISH) with different BAC probes and the array technique, in order to map the breakpoints. The patient has a 16q21 --> qter duplication, with a 4q35 --> qter monosomy, which we assume does not contribute to the abnormal phenotype. This is the first reported case of postnatal survival to the age of 7 years, an unusually long time in this chromosomal syndrome.
Subject(s)
Abnormalities, Multiple/genetics , Chromosome Aberrations , Chromosomes, Human, Pair 16/genetics , Chromosomes, Human, Pair 4/genetics , Heart Defects, Congenital/genetics , Intellectual Disability/genetics , Trisomy/genetics , Abnormalities, Multiple/mortality , Adult , Female , Follow-Up Studies , Heart Defects, Congenital/mortality , Humans , In Situ Hybridization, Fluorescence , Infant, Newborn , Intellectual Disability/mortality , Karyotyping , Male , Monosomy , Survival Rate , Translocation, GeneticABSTRACT
BACKGROUND: This report describes the sixth case of an unusual association: Down syndrome with achondroplasia. It also analyzes the effects of both of these disorders on patient phenotype. METHODS: A male infant was evaluated for Down syndrome. His appearance also suggested a diagnosis of achondroplasia. The child was evaluated by physical examination, radiography, cytogenetic study, and mutation analysis. RESULTS: Chromosome analysis showed a karyotype of 47,XY,+21 in all 30 cells analyzed. Radiographic examination showed typical findings of achondroplasia, such as disproportionately large skull, shortening of limb segments, and lumbar lordosis. FGFR3 screening showed a heterozygous G1138A mutation. CONCLUSIONS: The interaction of these two distinct genetic disorders in the same patient produces a phenotype typical of each syndrome with some overlapping signs. This case represents de novo origin of two disorders that both may be parental-age related.
Subject(s)
Achondroplasia/complications , Down Syndrome/complications , Receptor, Fibroblast Growth Factor, Type 3/genetics , Achondroplasia/genetics , Achondroplasia/pathology , Amino Acid Substitution , Down Syndrome/genetics , Down Syndrome/pathology , Down Syndrome/psychology , Genotype , Humans , Infant, Newborn , Karyotyping , Male , Maternal Age , Mutation, Missense , Paternal Age , Phenotype , Point MutationABSTRACT
PURPOSE: Ocular anomalies have been associated with numerous chromosomal abnormalities. This report describes partial trisomy 3q in a two-month-old girl with dysmorphic features of the Dup3q phenotype and severe eye and cerebellar malformations. METHODS: Clinical examination and chromosomal analysis were conducted. RESULTS: The karyotype of the propositus was 46,XX, ins(3)(pter --> p25::q27 --> q21::p25 --> qter). She had an abnormal head shape, low-set malformed ears, coarse facies, short webbed neck, abnormal foot position, polycystic kidney, and spina bifida. There was also bilateral microphthalmia that was more severe on the right side, microcornea, and corneal opacity. She had posterior fossa abnormalities, including cerebellar vermis hypoplasia suggestive of a Dandy-Walker (DW) malformation. CONCLUSIONS: This girl with an intrachromosomal duplication of distal 3q and typical phenotype belongs to the severe end of the spectrum for such cases. The ocular manifestations of the 3q duplication syndrome provide additional evidence of the involvement of developmental eye genes in this chromosomal segment.
Subject(s)
Cerebellum/abnormalities , Chromosomes, Human, Pair 3 , Dandy-Walker Syndrome/genetics , Eye Abnormalities/genetics , Trisomy/genetics , Cerebellum/diagnostic imaging , Cerebellum/pathology , Dandy-Walker Syndrome/diagnosis , Eye Abnormalities/diagnostic imaging , Fatal Outcome , Female , Gene Duplication , Humans , Infant , Karyotyping , Microphthalmos/genetics , Phenotype , Tomography, X-Ray Computed , UltrasonographyABSTRACT
BACKGROUND: The phenotypic expression of an additional chromosome 9 causes a very broad clinical spectrum of anomalies. The prognosis for infants with non-mosaic tetrasomy 9p is poor, and they usually die at a very early age. CASE: In this article we present a new case of complete tetrasomy 9p in a newborn girl with multiple dysmorphologic features. Cytogenetic studies were carried out by CBG, GTG, and QFQ chromosome bandings, as well as by fluorescence in situ hybridization (FISH). The cytogenetic findings for the newborn girl showed an extra chromosome interpreted as an isochromosome 9p. The karyotype was characterized as 47,XX,+mar.ish i(9)(p10)(wcp9+). The parental chromosomes were normal. CONCLUSIONS: The karyotype and clinical features of the newborn girl (e.g., typical craniofacial dysmorphism, severe skeletal anomalies, and visceral and genito-urinary malformations), compared with cases reported in the literature, give additional support to a clinical definition of this chromosomal syndrome.
