trisomy for d group chromosomes is common through nondisjunction in meiosis and anaphase lagging1,2 ) . however , trisomy 14 mosaicism is a rare chromosomal defect with approximately 30 cases reported in the literature . unlike other acrocentric chromosomes , lethality of complete trisomy 14 or less susceptibility to errors of disjunction of chromosome 14 may result in spontaneous abortion of embryos and fetuses1,3,4 ) . mosaic trisomy 14 involves complete trisomy with an extra chromosome 14 in 58% of cases and partial trisomy . we describe the first live born case with complete trisomy 14 mosaicism ( 47,xx,+14/46,xx ) in korea and compare the characteristic phenotypes between complete and partial trisomy mosaicism based on the reported cases to date . a 17-month - old female was referred for evaluation of delayed development and abnormal skin pigmentation on the trunk and both extremities . the patient was born at 40 weeks gestational age to a 37-year - old gravida 1 para 1 healthy mother with no drug history during pregnancy . the delivery was by cesarean section due to a uterine myoma in the mother , and uncomplicated . at birth , the body weight was 1,800 g ( small for gestational age , < 3rd percentile ) . the mother could not remember the height , and head and chest circumferences of her newborn . at 4 months of age , the patient underwent a cleft lip repair and a ventricular septal defect was noted on echocardiography at that time . at the age of 17 months , weight was 7.3 kg ( < 3rd percentile ) , height was 70.5 cm ( < 3rd percentile ) , and head circumference was 46.5 cm ( 50th percentile ) . the patient had a dysmorphic face ( frontal bossing , micrognathia , deep - set eyes , broad nasal bridge , anteverted nose , high arch palate , cleft lip , and triangular and wide lip ) and simian crease on both hands . the skin was hyperpigmented with a reticular pattern on the trunk and limbs ( fig . development was globally delayed by about 10 months , corresponding to same - aged korean infant and child developmental testing . chromosome analysis of the patient was performed from peripheral blood lymphocyte cultures with gtw - banding . this is the first report of a live born female with complete trisomy 14 mosaicism in korea . trisomy 14 mosaicism is characterized by a clinical distinct phenotype , such as delayed development , failure to thrive , facial dysmorphism , congenital heart disease , skin pigmentation , and genitourinary anomalies , although trisomy 14 mosaicism and other chromosomal abnormalities are difficult to distinguish4 - 6 ) . our patient was suspected not specific trisomy 14 but certain chromosomal anomaly due to nonspecific morphologic characteristics . but skin pigmentation let us consider trisomy 14 as well as other chromosomal abnormalities including hypomelanosis of ito , incontinentia pigmenti , pallister - killian syndrome , and whorled nevoid hypermelanosis7,8 ) . to summarize the clinical distinct phenotype for trisomy 14 , we compared clinical phenotype for complete and partial trisomy based on previously reported cases ( table 1 ) . the phenotype between the two groups was similar although the incidence of seizures is more in patients with complete than partial trisomy 14 mosaicism9 - 14 ) . the similarity between the two groups could suggest that the 14q abnormality might result in a clinically - recognizable phenotype1 ) . the phenotype of our patient was also similar to previous reported korean cases for partial trisomy 14 mosaicism , except for abnormal skin pigmentation15,16 ) . the phenotype in trisomy 14 mosaicism is not related to trisomic type such as complete and partial patterns9 ) , as well as the percentage of trisomic cells in reported cases14 ) . trisomy 13 also has no relationship between the percentage of trisomic cells and the level of cognition17 ) . however , the differing percentage or tissue distribution of trisomic cells in case of trisomy 21 mosaicism reflects the variability of clinical phenotype18 ) . life expectancy of patients with trisomy 14 has not been studied , but about two - thirds of patients with trisomy14 mosaicism survive relatively free of serious medical problems after infancy9 ) . because of the variability of involved 14q segment and the possibilities of low grade mosaicism in trisomy 14 mosaicism , the frequency of trisomy 14 mosaicism might be underestimated . low - level mosaicism can be masked by high percentage of normal cell line and may be difficult to diagnose only by cytogenetic method . array - cgh could be helpful in detecting of low - level mosaicism which was not detected by conventional karyotyping14 ) . hence , we should consider array - cgh as well as cytogenetic study if the patient is clinically suspected trisomy 14 .
trisomy 14 mosaicism is a rare chromosome disorder characterized by delayed development , failure to thrive , and facial dysmorphism . only approximately 30 trisomy 14 mosaicism cases have been reported in the literature because trisomy 14 is associated with early spontaneous abortion . 
 we report a case of a 17-month - old girl with abnormal skin pigmentation , delayed development , facial dysmorphism , and failure to thrive with the 47,xx,+14/46,xx chromosome complement .