49,XXXXY syndrome is a type of chromosome abnormality characterized by the presence of 3 extra X chromosomes in males. It is sometimes referred to as a variant of Klinefelter syndrome, but differs from Klinefelter syndrome in many ways and is more severe.

49,XXXXY syndrome is a chromosomal condition in boys and men that causes intellectual disability, developmental delays, physical differences, and an inability to father biological children (infertility). Explore symptoms, inheritance, genetics of this condition.

Klinefelter综合征又称先天性睾丸发育不全，最常见的核型为47，XXY，其余则主要包括额外的X或Y染色体或嵌合体。 该病在男婴中的发生率为1/100 000~1/85 000，是男性不育最常见的遗传学病因。 49，XXXXY是Klinefelter综合征的一种罕见核型，其发生可能缘于初级或次级卵母细胞在减数分裂时的染色体不分离，从而形成包含4条X染色体的卵细胞与正常精子受精而成。 Villamar等 [1] 借助X连锁限制性片段长度多态性分析，证实这类病例中大约88%的X染色体为母源性。

五染色體X症候群（pentasomy X）又稱為49，XXXXX，這是一种染色体畸变，患者為有五条X染色體的女性，而不是正常的两条 [1] 。 症状包括可能智能障礙、身材矮小、 耳朵位置偏低 （ 英语 ： Low-set ears ） 、 肌肉張力低下 （ 英语 ： Hypotonia ） 和 發展遲緩 [2] [1] 。 并发症包括可能合併先天性心脏病 [3] 。

XXXXY syndrome, also known as 49,XXXXY syndrome or Fraccaro syndrome, is an extremely rare aneuploidic sex chromosomal abnormality. It occurs in approximately 1 out of 85,000 to 100,000 males. [1] [2] [3] This syndrome is the result of maternal non-disjunction during both meiosis I and II. [4]

49,XXXXY syndrome is a chromosomal condition that causes intellectual disabilities, developmental delays, changes in sex characteristics and other physical features, and an inability to have biological children (infertility). Some of these …

49, XXXXY syndrome is a rare sex chromosomal disorder. A 5-month-old boy had failure to thrive and multiple congenital anomalies including microcephaly, facial dysmorphism (hypertelorism, megacornea, cleft palate, and micrognathia), obvious heart murmur, umbilical hernia, microphallus, and mild clen …

The 49,XXXXY syndrome represents a chromosomal anomaly of the aneuploidic type characterized by the presence of three extra X chromosomes in males. It has an annual incidence of 1/85,000 to 1/100,000 male births.

49,XXXXY syndrome is a type of chromosome abnormality characterized by the presence of 3 extra X chromosomes in males. It is sometimes referred to as a variant of Klinefelter syndrome, but differs from Klinefelter syndrome in many ways and is more severe.

49,XXXXY syndrome is a chromosomal condition that causes intellectual disabilities, developmental delays, changes in sex characteristics and other physical features, and an inability to have biological children (infertility).