background participants

Participant 086

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Female, age 28 with Landau-Kleffner syndrome and progressive lower limb weakness caused by changes in the CHKB gene

Date of Report

Sep 21, 2018


The participant’s development was typical until the age of three when she experienced sudden regression and lost her ability to speak. She has a history of abnormal brain activity (abnormal EEG) but has not had seizures. She received a diagnosis of Landau-Kleffner syndrome at age 3. She has significant difficulty sleeping and sleeps no more than two hours at night.

Around age 21, she started falling frequently. It is unclear if the falls are caused by muscle disease, motor difficulty, or drop attacks. Her difficulty walking has worsened in the past few year; she can walk short distances with assistance at this time.

Other symptoms include multiple café-au-lait spots, swirling, streaky patches of dark pigmentation on the skin of her arms (hyperpigmentation), autism, obsessive-compulsive behavior, and short stature.

Symptoms / Signs
  • Absent speech and abnormal brain activity (Landau-Kleffner syndrome)
  • Autism
  • Obsessive-compulsive behavior
  • Difficulty sleeping (sleep disturbance)
  • Short stature
  • Lower limb muscle weakness
  • Difficulty walking (gait disturbance)
  • Low frontal hairline (low anterior hairline)
  • Scaly patches and red skin on scalp (seborrheic dermatitis)
  • Increased distance between the eyes (telecanthus)
  • Broad neck
  • Swirling darker colored patches of skin on arms (hyperpigmentation of the skin)
  • Brown birthmarks (multiple café-au-lait spots)
  • Increased body hair (hirsutism)
  • Urinary and bowel incontinence
Current Treatments
  • Cleocin-T – skin rash
  • Clonazepam – seizures
  • Lamictal – abnormal EEG
  • Nystatin – infection
  • Seroquel, Zoloft – obsessive-compulsive behavior
Prior Treatments
  • Dilantin – speech
Considered treatments
Previously Considered Diagnoses
  • Congenital disorder of glycosylation
  • Metabolic condition
  • Mitochondrial condition
Other Photographs
Genetic Variants of Interest

In 2019, clinicians and researchers identified the following genetic changes to be causing the participant’s symptoms:

Inheritance Pattern
Position (hg19)
DNA Change
Protein Change
Autosomal Recessive
chr20:g.51020982C>G & g.51021060G>A
c.224+5G>C & c.151C>T
N/A & p.Gln51Ter

If this participant sounds like you or someone you know, please contact us!


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