Neurobehavioural phenotype of an 8-year-old girl with haploinsufficiency at the BDNF locus

TrkB (9-year-old boy)BDNF (9-year-old girl)
Social communication questionnaire25 (autism trait)7 (normal)
Intelligence (WISC-III)
    Full-scale IQ42 (<0.1)56 (0.2)
    Verbal IQ48 (<0.1)59 (0.3)
    Performance IQ46 (<0.1)59 (0.3)
    Digit span (STM) subtest1 (very low)4 (very low)
    Sutherland Memory Questionnaire139 (impaired)43 (normal)
    General memory quotientNA<50 (<0.1)
    Visual immediate memoryNA75 (5)
    Visual delayed memoryNA82 (12)
    Verbal immediate memoryNA50 (<0.1)
    Verbal delayed memoryNA50 (<0.1)
    Attention/concentrationNA57 (0.2)
    LearningNA54 (<0.1)
    Delayed recognitionNA50 (<0.1)
RBMT score4 (impaired)10 (impaired)
    BPVS<41 (<0.1)66 (1)
    TROG (years [percentile])4 (<0.1)5 (1–5)
    Reading70 (2)67 (1)
    SpellingNA63 (1)
    Reading comprehensionNA58 (0.3)
Numeracy (WOND)
    Mathematics reasoning59 (0.3)64 (1)
    Numerical operations60 (0.4)59 (0.3)
Attention (TEA-Ch)
    Selective visual attention1 (<0.2)1 (<0.2)
    Sustained attentionNA3 (<1.5)
  • Data are scores (percentile) unless otherwise indicated. A summary of the performance of both the proband and the previously reported patient with a mutation in TrkB on a range of cognitive assessments. Average performance on the Wechsler Intelligence Scale for Children-III (WISC-III), Children’s Memory Scale (CMS), Wechsler Objective Reading Dimensions (WORD), Wechsler Objective Numerical Dimensions (WOND), Test for Reception and Grammar (TROG), Test for Everyday Attention for Children (TEA-Ch), and British Picture Vocabulary Scale (BPVS) is 100 ± 15 (normal range 85–115); average score for subtests, 10 ± 3 (7–13). Mean score (±SD) on the Sunderland Memory Questionnaire for healthy individuals aged between 10 and 27 years is 58.8 ± 8.3 (A.-L.R.A., J.R.H., unpublished observations). Percentiles and age-equivalent scores are shown where available. A percentile score of <10% indicates an impairment of clinical significance. NA, not available due to individual being unable to complete the test (full details and references in online appendix 1); RBMT, Rivermead Behavioral Memory Test.