diagnosed as complete trisomy 9 by conventional cytogenetic techniques , fluorescence in situ hybridization ( fish ) studies of metaphase and interphase blood cells and skin fibroblasts could identify the presence of euploid and trisomy 9 cells . therefore , it has been suggested that trisomy 9 may be viable only in the mosaic state , which might be remained undetected in cases diagnosed by conventional chromosome analysis of a few metaphase cells or only one tissue type . the main features of trisomy 9 syndrome are  bulbous  nose , microphthalmia , dislocated limbs and other anomalies of skeletal , cardiac , genitourinary , and central nervous system ( cns ) . skeletal malformations reported in this disorder , include congenital hip dislocation , calcaneovalgus deformity , joint hyperflexation , punctate mineralization , scoliosis and kyphosis . patients with mosaicism survive longer than non - mosaics , but it had been believed that the degree of mosaicism in lymphocytes or fibroblasts does not associate with survival or degree of impairment . atypical signs reported in trisomy 9 patients include hemivertebra , holoprosencephaly , sex reversal , an unexpectedly normal psychomotor development , no evident external or internal congenital anomalies and congenital leukemia . partial trisomy 9p cases have been also reported with dysmorphic features , congenital anomalies , severe mental retardation and gross delay in speech . in this report , we present a male case of mosaic trisomy 9 with higher survival than the mean survival mentioned for this chromosome disorder and no cns structural abnormality , which shows the wide range of clinical manifestation of this disorder . the patient is a 2.5-year - old boy , the first child to a normal non - consanguineous parent . he was delivered by cesarean section at 36 weeks of gestation because of fetal intermittent bradycardia and intra - uterine growth retardation . at the time of birth , his head circumference was 35 cm . at the age of 3 months other signs include low - set slightly malformed ears , deeply - set malformed eyes , small palpebral fissures , micrognathia , developmental delay and unilateral optic hypoplasia ( figure 1a and 1b ) . although he had neck control at the age of 5 months , he was noted to be developing slowly afterwards , particularly in fine and gross motor skills . at the age of 2 years low - set malformed ears , deeply - set malformed eyes , small palpebral fissures and micrognathia are seen in patient s face . cytogenetic studies were performed on peripheral blood lymphocytes of the child and both of his parents . fifty metaphases were analyzed and karyograms were prepared using the cytovision computer - assisted karyotyping system version 4.1 ( applied imaging , newcastle upon tyne , uk ) . cytogenetic analysis with g banding showed karyotype 47xy,+9 in 44% of peripheral lymphocytes examined ( 47xy,+9 , 46xy ) ( figure 2 ) . chromosome analysis shows both of the mosaic karyotypes , 47xy,+9 ( a ) and 46xy ( b ) . cytogenetic studies were performed on peripheral blood lymphocytes of the child and both of his parents . fifty metaphases were analyzed and karyograms were prepared using the cytovision computer - assisted karyotyping system version 4.1 ( applied imaging , newcastle upon tyne , uk ) . cytogenetic analysis with g banding showed karyotype 47xy,+9 in 44% of peripheral lymphocytes examined ( 47xy,+9 , 46xy ) ( figure 2 ) . chromosome analysis shows both of the mosaic karyotypes , 47xy,+9 ( a ) and 46xy ( b ) . trisomy 9 is a rare chromosome disorder in liveborn infants , but accounts for 2.4% of spontaneous abortions . despite the difference in survival between mosaic and complete trisomic patients , previous reports demonstrated ocular manifestations of trisomy 9 patients as deeply - set eyes , small palpebral fissures , telecanthus , keratolenticular adhesion and marked iris hypoplasia . these manifestations are similar to peters anomaly , ocular lesions associated with aplasia of the optic nerve and lowe s and potter s syndrome . in the patient presented here , in addition , unlike most cases of trisomy 9 , no skeletal anomaly was detected in our patient . however , patients with mosaicism may survive beyond the first year of life . a few cases of mosaic trisomy 9 , albeit with a low proportion of trisomic cells in lymphocytes , have been reported who survive until late childhood . although most of patients had severe mental impairment , only in one third of them gross cns structural abnormalities similar to most of trisomy 9 patients , no cns structural anomaly was detected in our patient . the most common reported malformation has been dandy - walker malformation , which is only found in complete trisomy 9 patients . other cns malformations , included dilated ventricles , structural abnormalities of the lobes , and altered cellular structure . an important issue raised in pnd is the variation in the percentage of trisomic cells in different tissues . in such cases , similar to some other cases reported in the literature , moderate developmental delay was seen in our patient , which implies that the range of motor and cognitive impairment in this chromosomal disorder is quite broad .
trisomy 9 is a rare chromosome disorder with high neonatal mortality . 
 it is often seen in mosaic form . 
 most patients who survive are severely mentally retarded . 
 the main features of this syndrome are  bulbous  nose , microphthalmia , dislocated limbs , and other anomalies of skeletal , cardiac , genitourinary , and central nervous system . 
 most patients have developmental and cognitive impairment . 
 patients with mosaicism survive longer than non - mosaics , but it was believed that the degree of mosaicism in lymphocytes or fibroblasts does not associate with survival or degree of impairment . in this report , we present a 2.5-year - old male case of mosaic trisomy 9 , to show the wide range of clinical findings in this chromosome disorder . 
 the patient had cardiac anomalies , inguinal hernia , and undescendent testes . 
 he had low - set slightly malformed ears , deeply - set malformed eyes , small palpebral fissures , micrognathia , developmental delay and unilateral optic hypoplasia . 
 the most prominent facial anomaly in this patient was eye anomalies . 
 cytogenetic analysis with g banding showed karyotype 47xy,+9 in 44% of peripheral lymphocytes examined ( 47xy,+9[22 ] , 46xy[28 ] ) . 
 his parents karyotypes were normal . 
 moderate developmental delay , which was detected in this patient shows that the range of motor and cognitive impairment in this chromosomal disorder is quite broad . 
 this fact should be considered in genetic counseling as well as prenatal diagnosis of this chromosomal disorder .