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Symptoms That Could Be Indicative Of An X & Y Chromosomal Variation

Symptoms - The Focus Foundation


Feeding Difficulties – trouble latching on or sucking from the bottle, or was a slow feeder

Texture Avoidance – coughs and/or gags when tasting new food textures

Delayed Ambulation – independent walking after 18 months of age

Congenital Muscular Torticollis – a tilting of the head towards the shoulder due to the shortening of the sternocleidomastoid muscle that is present from birth

Delayed Speech – rarely babbling between 6 and 12 months, or producing no sounds; a “quiet” baby

Symptoms - The Focus Foundation


Hypotonia – low muscle tone, particularly in the trunk

Speech and Language Delay – receiving services for speech delay

Sensitivity to Touch – tags in clothing, fusses at haircuts, dislikes getting hair shampooed

Motor Discoordination – difficulty in gross motor skills and fine motor tasks, contralateral movements

By age 3, child uses very few three-word combinations.

Symptoms - The Focus Foundation

School Age

Behavioral Outbursts – seems to ‘explode’ for no reason several times per day

Shyness – more shy or timid than other children in social settings or at school

Clumsiness – falling for no reason, bumping into things often, avoiding sports

Social Language Differences – expressive communication is often delayed in comparison to auditory comprehension, and there could be an incidence of social anxiety

Fine Motor Skills – has difficulty with handwriting, using scissors, hands tire

Reading delays

Symptoms - The Focus Foundation


Delayed Puberty – has not entered pubertal development at same age as peers

Pes Planus – flat-footedness, particularly if only member of family who has it

Tall for his age – height above the 95th centile

Language-based Learning Disorder – persistent difficulty with language-based learning, particularly reading and/or expressive vocabulary

Attentional issues – Attention Deficit Hyperactivity Disorder (ADHD), Attention Deficit Disorder (ADD)

Executive dysfunction and associated organization and planning deficits

Decreased muscle tone and strength


  • To identify children with Dyslexia who also have an X & Y Chromosomal Variations as early as possible
  • To detect children with Dyslexia who also have developmental dyspraxia
  • To determine the characteristic profile that places children “at risk” factors for dyslexia between three and five years of age

Our X & Y Disorder Research

The Focus Foundation’s efforts are geared toward 3 of the 4 known X & Y Variation disorders. Of the other three variations:

Only 25% of males with 47,XXY are ever diagnosed during their lifetimes; fewer than 10% of 47,XXY individuals are identified prior to adolescence. This means that millions of affected children remain undiagnosed–often because they are commonly misdiagnosed as simply having speech or motor delays. More than 500,000 people are believed to have 47,XXY disorders in the United States alone, with an equal distribution across all racial and socio-economic groups.

Based on scientific studies, it is important to consider early hormonal replacement therapy (EHRT) for 47,XXY boys (who experience decreased testosterone production during three critical developmental periods) before they are 18 months old. Testosterone treatment given then has been shown to have a positive impact on brain function through 9 years of age…READ MORE

At least 85% of those with 47,XYY are never diagnosed. 47,XYY boys consistently present with language-based Learning Disabilities and difficulties with Motor Planning–both issues that are related to the high rate of dyspraxia and dyslexia associated with the disorder. However, 47,XYY boys are commonly misdiagnosed as simply having speech or motor delays.

Boys with 47,XYY typically reach an average height of between 6’3” and 6’5”…READ MORE

As many as 1 in 900 girls have 47,XXX. Unfortunately, millions of affected girls are undiagnosed. Girls who are prenatally diagnosed and receive early intervention services typically exhibit fewer and less severe cognitive disabilities.

There is an equal distribution of 47,XXX across all racial and socio-economic groups…READ MORE

Boys with 48,XXYY consistently exhibit Language-Based Learning Disabilities (LLD) and difficulties with Motor Planning, issues that are related to the high rate of dyslexia associated with the disorder. However, they seem to be stronger in math and such visual-spatial activities as assembling puzzles or remembering directions.

Intellectual disabilities are common in 48,XXYY, with average full-scale IQs in the range of 70-80. Verbal IQs are seen to be significantly lower than performance IQs, due to language-based learning difficulties…READ MORE

48,XXXX (also known as Tetrasomy X or Tetra X) is a rare sex chromosome disorder that was first identified in the early 1960s. Since that time, approximately 100 cases have been reported, although less than 50 are described in scientific literature. Due to the scarcity of this female chromosomal variation, it is difficult to define a common phenotypic presentation. A lack of congenital malformations, mild dysmorphology, and varied developmental trajectory suggests that 48,XXXX is largely underdiagnosed…READ MORE

48,XXXY can result from meiotic or mitotic nondisjunction (errors in chromosomal separation) and is often considered a variant of Klinefelter syndrome (47,XXY). However, boys with 48,XXXY often exhibit a more complicated neurodevelopmental profile than boys with 47,XXY…READ MORE

The first case of 49,XXXXY syndrome was reported in the 1970s, and this chromosomal variation remains one of the rarest sex chromosome disorders. 49,XXXXY results from nondisjunction (errors in chromosomal separation) of the X chromosome occurring during both Meiosis I and Meiosis II…READ MORE

Penta X Syndrome is an extremely rare chromosomal disorder that only affects females. While girls normally only have two X chromosomes, girls with Penta X have five X chromosomes. As of 2011, less than 40 cases have been reported.…READ MORE

Klinefelter Syndrome & Other Names You May hear

X & Y Variations is a neurogenetic disorder known by many names, among them: Sex Chromosome Disorders, X & Y Chromosomal Variations, Sex Chromosome Anomaly and Sex Chromosome Aneuploidy Variations. Within the disorder are many sub-categories, which are identified by names including 47 XXY (Klinefelter Syndrome), 49 XXXXY, Tetrasomy X, 49 XXXXXX, Pentasomy X, 48 XXY.

What You Can Do Now

If you have had a prenatal diagnosis or feel you may have a child with developmental delays or developmental dysfunction the following options are designed to help you towards the next step in treatment or early diagnosis.

Symptoms - The Focus Foundation


Take The Child Questionnaire



Learn About Chromosomal Microarray

Chromosomal Testing


Syndrome-specific Therapy