MULTIPLE CONGENITAL ANOMALIES IN A CHILD WITH 47,XY,+der(8;9)(p10;p10): A CASE REPORT.

Summary: Multiple congenital anomalies in a child with 47,XY,+der(8;9)(pI0;pl0): a case report: Complex small supernumerary marker chromosomes (sSMC) constitute one of the smallest subgroups of sSMC in general. Complex sSMC consist of chromosomal material derived from more than one chromosome. We report a complex sSMC derived from chromosomes 9 and 8, characterized as der(8;9)(plO;plO) resulting from unbalanced transition of maternal balanced translocation. Besides dysmorphic face and mental-motor retardation, the patient had Dandy-Walker malformation (DWM) in cranial MR also. As far as we are concerned, this is the first complex sSMC case comprising short arms of 8th and 9th chromosomes.Key-words: sSMC Trisomy 8p - Trisomy 9p.INTRODUCTIONSmall supernumerary marker chromosomes (sSMCs) are anormally extrachromosomal structures with sizes equal to or smaller than chromosome 20 in the same metaphases. Due to their small size they cannot be characterized by conventional cytogenetic analysis only and it is difficult to establish their correlations with specific clinical findings (9,11). The molecular techniques are required in order to achieve comprehensive characterization of the sSMCs (11). The incidence of SMC is around 0.14-0.72 per 1000 live births (4). While they occur de novo in 77% of the cases, they are inherited in 23% of them (16% inherited from mother, 7% from father) (16). sSMCs may originate from any of 24 human chromosomes (5), majority of the SMCs (70%) originate from the pericentric regions or short arms of the acrocentric chromosomes (16). Most of them originate from 15th and 22nd chromosomes respectively (5). sSMCs originating from non-acrocentric chromosomes and complex marker chromosomes containing more than one chromosome material are rare (5,16). The phenotypical features related to sSMCs depend on inheritance, chromosomal origin, content of the marker and its structure. The phenotype varies from normal to severe abnormalities (2). Herein we present the first complex sSMC derived from chromosomes 9 and 8, characterized as der(8;9)(p 10;p 10) resulting from unbalanced transition of maternal balanced translocations.CASE REPORTThe presented patient is a 2.5-year-old baby boy with der(8;9) (pl0;pl0). He was born at term by normal vaginal delivery as 3900 gr as the second living birth of the third pregnancy of a 31 year-old-mother. There were no hallmarks in family history. He had a history of hypotonicity in perinatal period. The baby was initiated phenobarbital on having a seizure when he was 3 months old. The patient who can still neither walk nor speak, hold his head erect when he was 1 year old and sat without support when he was 1.5 year old. Physical examination showed height of 88 cm (25-50p), weight of 13.8 kg (25-50p) and his head circumference of 48 cm (10-25p). He had an asymmetric and rough face, prominent forehead, hypertelorism, strabismus, downslanting palpebral fissures, deep set eyes, broad and thick nasal root, short and wide philtrum, thin upper lip, thick and everted lower lip, prominent nasolabial folds, full cheeks, downtumed oral commissures, malocclusion, high arched palate, retrognathia, low and posteriorly rotated dysplastic auricles, short neck, low-set posterior hairline, bilateral brachydactyly, clinodactyly, cutaneous syndactyly in 2,3,4 and 5th fingers, hypoplastic nails, wide first toes, cutaneous syndactyly in 2,3 and 4th fingers and hypoplastic nails in feet (Fig. 1). In genital examination, the left testis was retractile and he had scrotal hypoplasia. Cranial magnetic resonance imaging (MRI) revealed a mild form of Dandy-Walker variant and he had dysrythmie waves on Electroencephalogram (EEG). The conventional cytogenetic analysis was applied to the patient because of his dysmorphic findings and marker chromosome was detected in all metaphases and his karyotype was described as 47, XY, +mar (Fig. 2). Analysis of parental chromosomes revealed a balanced translocation [46,XX,t(8;9)(p 10;p 10)] in the mother while the paternal chromosomes were intact (Fig. …