48, XYY,+13 Karyotype in a liveborn infant

A liveborn male infant, with typical features of trisomy 13 , was found to have a combined autosomal and gonosomal trisomy, 48,XYY, + 13. To our knowledge, this is the first report of co-existing 13 trisomy and XYY chromosome complement.     

48,XXX,+21一例

患儿 女,8天,系第3胎第3产,足月顺产.出生时有轻度窒息,孕期未进行产前检查.患儿出生时父亲37岁,母亲36岁,非近亲婚配,父母表型、智力均无异常,前2胎为一子一女,分别为15岁及13岁,生长发育、智力均正常,自述无家族性遗传性病史.     

Prenatal diagnosis of 48,XYY, + 21 ascertained through ultrasound anomalies

During a routine ultrasound study on a fetus at 21 weeks, nuchal edema was noted. At 21 weeks, repeat ultrasound study at our unit showed scalp and neck edema and a femur length/biparietal diameter ratio below the mean. Transabdominal chorionic villus sampling identified a 48.XYY, + 21 chromosome constitution. The fetus had normal internal/external genitalia and signs of Down syndrome.     

45,X/47,XYY mosaicism: clinical discrepancy between prenatally and postnatally diagnosed cases

45,X/47,XYY mosaicism is a rare chromosomal disorder with clinical information limited to 11 postnatal cases in the literature and with uncertainty regarding prenatal prediction of phenotype and prognosis. We report on 7 new cases of 45,X/47,XYY mosaicism, three detected prenatally and 4 diagnosed postnatally. A clinical comparison of the cases of 45,X/47,XYY mosaicism is presented together with a literature review.     

Prenatal diagnosis of 48,XYY, +21 ascertained through ultrasound anomalies.

During a routine ultrasound study on a fetus at 21 weeks, nuchal edema was noted. At 21 weeks, repeat ultrasound study at our unit showed scalp and neck edema and a femur length/biparietal diameter ratio below the mean. Transabdominal chorionic villus sampling identified a 48.XYY, +21 chromosome constitution. The fetus had normal internal/external genitalia and signs of Down syndrome.     

Down''s Syndrome with 47,XX,+21/47,XX,+mar Mosaicism

A four-year-old girl with typical Down's syndrome is described. She has 47,XX,+21 karyotype in skin and lymphocytes and 47,XX,+mar karyotype in some lymphocytes. Autoradiography and fluorescent analyses have failed to identify the +mar chromosome which has the appearance of a `D' chromosome but which may involve a translocation to a chromosome No. 21. However, the mechanisms of its formation and its significance are not certain.     

Double non-disjunction in maternal meiosis II giving rise to a fetus with 48,XXX,+21.

We describe a prenatally detected case of double trisomy involving chromosome 21 and the X chromosome (48,XXX,+21) along with determination of the segregation errors responsible for the double aneuploidy. The patient was ascertained as a result of an abnormal maternal serum analyte screen showing an increased risk for fetal Down's syndrome. Following determination of the abnormal karyotype, pregnancy termination was elected. Microsatellite polymorphisms and cytogenetic heteromorphisms were used to determine that both aneuploidies arose as a result of non-disjunction in maternal meiosis II. These results support hypotheses that a segregation defect at a cellular level may cause non-disjunction involving more than one chromosome.     

Double trisomy 48,XXX,+18 in a newborn

We report the 6th case of double trisomy X and 18, ie, 48,XXX,+18. The infant lacked overlapping fingers, simian creases, and structural heart disease and is alive at 275 days. Two X chromosomes were late replicating. Anomalies of the hands and kidneys involved only the right side in the present case; review of the five previous cases of 48,XXX,+18 also showed that anomalies of kidneys, hands, and ears affected predominantly the right side in three patients.     

A prenatally diagnosed patient with full monosomy 21: ultrasound, cytogenetic, clinical, molecular, and necropsy findings

We report on a patient with a full monosomy 21 (FM21) prenatally diagnosed in cord fetal blood, and subsequently confirmed in other tissues. Subtle chromosomal translocations of chromosome 21, were ruled-out by FISH using both painting and 21q telomeric probes. Microsatellites analysis demonstrated the paternal origin of the single chromosome. The propositus showed at 32 weeks of gestation a severe intrauterine growth retardation and microcephaly. He was born with multiple congenital malformations, hypotonia, microcephaly, bilateral microphthalmia (more severe on the left), facial dysmorphism, agenesis of the external auditory meatus, redundant skin in the neck, narrow chest, flat scrotum, cryptorchydism, hypospadias, micropene, camptodactyly, nail hypoplasia, and abnormal palmar and plantar creases. The patient died in the first day of life. At necropsy, micrencephaly, semilobar holoprosencephaly, polimicrogyria, ocular abnormalities, skeletal anomalies, congenital heart disease, and agenesis of right kidney were also observed. To our best knowledge, this case is one of the most completely patient studied with FM21.     

Three successive prenatal diagnoses of 47,XY,+21

Within 3 working days in September, 1974, we made three prenatal diagnoses of 47,XY,+21 from three women of advanced maternal age. Two were 37 and 38 years old, respectively, and nulliparous. One was 42 years old and had four normal children. The possibility of cell contamination arose when the second diagnosis of trisomy 21 and a male fetus was made. This suspicion increased when the third case was found within 3 working days. All three cases were then studied with both Q and G banding for identification of individual chromosome markers. Fortunately, the distinction was clear by Q-banding. Each case showed characteristic Q-banding polymorphisms in No. 3 and No. 21 chromosomes. It was evident that these were three separate cases. Problems relating to diagnosis of two or more successive identical trisomies of the same sex can be resolved by banding techniques. The response each family had to learning the diagnosis is presented and discussed.     

Mosaic Down''s syndrome with de novo 45,XX,-21,-22,+t(21q;22q)/46,XX,-21,+t(21q;21q) rearrangement.

The occurrence of mosaic Down's syndrome with two independent Robertsonian translocation cell lines is very rare. Such a patient is reported here, in whom an unbalanced Robertsonian translocation between two chromosomes 21 was detected in the majority of cells. The patient also revealed a minor cell line with a second Robertsonian translocation involving a chromosome 21 and a 22. The chromosome translocations detected in this patient were de novo in origin.     

Interstitial deletion of chromosome 4q diagnosed prenatally.

The prenatal diagnosis of 4q deletion was made as a result of amniocentesis for high serum alphafetoprotein.     

Down's syndrome associated with two Robertsonian translocations, 45,XX,−15,−21,+t(15q21q) and 46,XX,−21,+t(21q21q)

A female infant with Down's syndrome was found to be a chromosomal mosaic with two cell lines in both blood and skin cells. One line carried a balanced 15/21 translocation, and the other line was effectively trisomic for chromosome 21 with a 21/21 translocation.     

Prognosis of prenatally diagnosed children with sex chromosome aneuploidy.

Sex chromosome aneuploidy (SCA) occurs in about 1/250 amniocenteses, and the significance of the long-term prognosis of fetuses with SCA is of concern to prospective parents and health care providers. Longitudinal studies in an unselected group of newborn infants with SCA diagnosed postnatally have refuted allegations of mental retardation but have documented an increased risk for developmental problems. Of the 530 phone consultations with parents faced with a prenatal diagnosis of SCA, 68% continued the pregnancy. Twenty of the oldest subsequently born children (now 7-14 years old) were available for follow-up. In this small sample and age group, the propositi are progressing developmentally at a rate comparable to their sibs and are doing better at school and in peer relations than the SCA group diagnosed postnatally. Only 2 have documented IQs as low as 90. The documented IQs of the remainder, none of whom are sex chromosome mosaics, are all over 110. The parent population in this prenatally diagnosed group is unique and different from that of the postnatally diagnosed group in that over 85% of them are college graduates, often professionals, and upper socioeconomic individuals. The developmental competence of this SCA sample may be attributable to the supportive environment provided by these families, all of whom made a conscious decision to continue the pregnancy.