FRAGILESYNDROME

Gopal Singh Charan 

Lecturer, SGL Nursing Institutes 

Semi, Jalandhar  X-linked diseases: 

  X-linked diseases are those for which the gene is present on the X chromosome.

  X-linked diseases show inheritance patterns that differ from autosomal diseases.

  This occurs because males only have one copy of the X chromosome (plus their Y

chromosome) and females have two X chromosomes.  X-linked genes are never passed from father to son.

  The Y chromosome is the only sex chromosome that passes from father to son.

  Males are never carriers – if they have a mutated gene on the X chromosome, it will be

expressed.  Males are termed hemizygous for genes on the X chromosome. 

FXS DEFINITION: 

Fragile X syndrome (Marker X syndrome ) is a genetic condition involving changes in the long

arm of the X chromosome. It is characterized by mental retardation.

INCIDENCE

•  Affects 1 in 3,600 males & 1 in 4,000- 6,000 females

•  1 in 260 women are carriers

•  1 in 800 men are carriers

•  Fragile X appears in all socioeconomic background

•  In Alabama, carriers and full mutations are estimated at 15,978

•  Second only to Down’s Syndrome as a genetic cause of mental retardation 

•  Unlike Down’s Syndrome, maternal age is not a factor 

•  The most common known cause of autism

•  About 30% of individuals with Fragile X Syndrome have autism

•  2-6% of individuals with autism have Fragile X Syndrome

•  Both Males and Females Can Have Fragile X Syndrome

BOYS

Approximately 85% of boys with F.M. have cognitive defects in the MR range (below 70) . The

 production of FMR1 protein is usually shut down

GIRLS

Approximately 70% of girls with F.M. have cognitive defects in borderline to M.R. range (below

70). Girls with more protein-producing cells tend to have higher IQs

 

CAUSES OF FRAGILE X SYNDROME

  Fragile X syndrome is a genetic disorder passed from parent to offspring through DNA.

  It is caused by mutation of the FMR1 gene (Fragile X mental retardation 1) on the X

chromosome.

  This mutation is the result of a trinucleotide repeat disorder.

  A section of the FMR1 DNA usually repeats a sequence known as CGG (cytosine,

guanine & guanine) 30-55 times. For someone with Fragile X syndrome, this section

repeats itself 200-800 times.

  This causes the FMR1 gene not to produce the FMRP (Fragile X mental retardation

 protein

  Mutation of this gene can vary between premature mutation and full mutation.

  Other disorders associated with this gene mutation:

  fragile x associated tremor/ataxia

  fragile x associated POF (premature ovarian failure

CLINICAL FEATURES

  Macrotia (Large ears)

  Long, narrow face  Prominent forehead

  Prominent, square chin

  High palate (roof of mouth)  Hand calluses

  Mitral valve prolapse (a leaky heart valve)

  Seizures

  Eye problems  Macroorchidism

  Ear infections

  Flat feet  Hyper extensible joints

  Eye problems in 20%-25%:

  Refractive errors  Strabismus

  Astigmatisms

  Seizures  Missing developmental milestones

COMMON DIFFICULTIES

  Sleeping

  Toilet training

  Socialization

  Play

Cognitive  The Fragile X mutation affects brain development and leads to a range of cognitive

delays.

 

  Developmental delays

  Mental impairment

  Learning disabilities

Difficulties with frontal lobe functions (“executive” functions):

Organization of information:

Acting on that information in an effective manner 

Focusing attention

Forming a plan and carrying it out

Behavior:

•  Attention deficits

•  Hyperactivity

•  Impulsivity

•  Autistic-like behaviors

•  Repetitive behaviors

•  Hand flapping

•  Hand biting

•  Gaze aversion

•  Extreme anxiety, shyness

•  Transition problems, difficulty adjusting to change

•  Cognitive/ Behavioral Strengths

•  Strong visual memory

•  Long term memory

•  Good verbal imitative skills

•  Desire to be social

•  Strong appreciation of humor 

•  Often receptive to helping or working cooperatively

•  Speech and Language :

•  Sensory Processing:

•  Sensory processing often seen in infants and young children:

•  Gross Motor problems.

•  Fine Motor problems.

•  Early/ Preschool Interventions:

•  Speech and language therapy

•  Occupational therapy

•  Occasional physical therapy

•  Settings with consistency, structure and routine

•  Total communication program

•  Simultaneous not sequential

•  Visual learners

•  Incidental learners

 

 

Suggested Recreational Opportunities

•  Trampolines

•  Bicycling

•  Swimming

•  Bowling

•  Soccer 

•  Gym/Fitness Center 

•  Softball

•  Martial Arts

•  Scouts

•  Choirs or other musical venues

•  Special Olympics

•  Challenger sports

Medications

•  Attention-related problems

•  Hyperactivity/ impulsivity

•  Mood disorders/ depression

•  Anxiety/ panic

•  Aggression

•  Obsessive/ compulsive symptoms

•  Bedwetting

•  Sleep disorders

•  Seizures

•  Self injury