Language skills and cognition in this cohort with pathogenic missense/loss-of-function variants disrupting FOXP2
| Case | Age at assessment (year range) | Receptive language | Expressive language | Intellectual abilities | Literacy impairment | |||
| Vocabulary | Grammar | Vocabulary | Grammar | Spelling | Reading | |||
| 1a | 6–8 | Mild* | Moderate† | Moderate‡ | Severe†† | Average¶ PRI 100 | Y | Y |
| 1b | 36–38 | Mild* | – | – | – | – | Y | Y |
| 1c | 30–32 | Average* | Average† | – | – | Average¶ PRI 100 | Y | Y |
| 1d | 60–62 | Average* | Moderate† | – | – | Average¶ MR 40 | Y | N |
| 2 | 6–8 | Severe* | Severe** | Severe** | Severe†† | Borderline‡‡ FSIQ 78 | Y | Y |
| 3a | 3–5 | Severe§§ | Severe§§ | Borderline¶¶ FSIQ 73 | Y | Y | ||
| 3b | 39–41 | – | – | – | – | – | N | N |
| 4a | 18–20 | Severe* | Moderate† | – | – | Mild*** FSIQ 67 | Y | Y |
| 4b | 18–20 | Moderate* | Severe† | – | – | Mild*** FSIQ 65 | Y | Y |
| 4c | 15–17 | Average* | Average† | – | – | Mild¶ FSIQ 62 | Y | Y |
| 5 | 6–8 | Severe§§ | Severe§§ | Average¶ PRI 94 Borderline¶ FSIQ 73 | Y | Y | ||
| 6 | 12–14 | Moderate††† | Moderate† | Severe‡ | Severe†† | Borderline¶ PRI 79 | Y | Y |
| 7a | 15–17 | Severe* | Moderate† | Mild | Below average‡‡‡ | Average¶¶ MR 10 | Y | Y |
| 7b | 15–17 | Average* | Moderate† | Severe¶¶ | Below average‡‡‡ | Average¶¶ MR 8 | Y | Y |
| 8a | 36–38 | Average* | Severe † | Mild*** | – | Moderate*** MR 4 | N | N |
| 8b | 15–17 | Moderate* | Severe† | Severe¶¶ | Below average‡‡‡ | Average¶¶ MR 10 | N | N |
| 9 | 18–20 | Severe* | Severe† | – | Severe‡‡‡ | Severe¶¶ MR 2 Mild§§§ FSIQ 67 | Y | Y |
| 10 | 9–11 | Average§§§ | Average† | Mild¶¶ | Below average‡‡‡ | Average¶¶ MR 17 | N | N |
| 11a | 39–41 | Average* | Average† | Average*** | Average‡‡‡ | Moderate*** MR 5 | N | N |
| 11b | 6–8 | Average§§§ | Severe† | Average¶¶ | Severe‡‡‡ | Average¶¶¶ FSIQ 92 | Y | Y |
| 12a | 3–5 | Severe* | – | Severe**** | Severe**** | Average¶¶¶ FSIQ 85 | NA | NA |
| 12b | 33–35 | – | – | – | – | – | N | N |
| 13 | 0–2 | Average†††† | – | Mild‡‡‡‡ | – | – | NA | NA |
| 14 | 3–5 | Severe†††† | – | Severe‡‡‡‡ | – | – | NA | NA |
| 15 | 3–5 | Average§§§§ | Severe‡ | Severe†† | – | Y | Y | |
| 16a | 42–44 | – | – | – | – | – | N | Y |
| 16b | 9–11 | Mild§§ | – | Mild§§ | – | Borderline¶¶ FSIQ 78 | Y | Y |
| 17 | 0–2 | Average†††† | – | Average‡‡‡‡ | – | – | NA | NA |
Average=−1 < SD; mild=−1 to −1.5 SD; moderate= −1.5 to −2 SD; severe=< −2 SD. Below average=a qualitative descriptor based on the analysis of a transcribed conversation speech sample.
*Peabody Picture Vocabulary Test.59
†Test for Reception of Grammar, Second and German Editions.60 61
‡Children’s Communication Checklist, Second Edition Semantics subdomain.61
§Wechsler Abbreviated Scale of Intelligence, Second Edition.62
¶Clinical Evaluation of Language Fundamentals Preschool, Second Edition.63
**Children’s Communication Checklist, Second Edition syntax subdomain.
††Kaufman Assessment Battery for Children, Second Edition.64
‡‡Clinical Evaluation of Language Fundamentals, Fourth and Fifth Editions.65 66
§§Wechsler Intelligence Scale for Children, Fourth and Fifth Editions.67 68
¶¶Wechsler Adult Intelligence Scale, Second and Fourth Editions.62 69
***Receptive One-Word Picture Vocabulary Test, Fourth Edition,70
†††Analysis of transcribed conversation speech sample.
‡‡‡Kaufman Assessment Battery for Children, Second Edition.64
§§§Snijders-Oomen Non-verbal Intelligence Test.71
¶¶¶Schlichting Test for Language Production.
****Communication and Symbolic Behaviour Scales Development Profile Infant-Toddler Checklist Understanding subdomain.72
††††Communication and Symbolic Behaviour Scales Development Profile Infant-Toddler Checklist Words subdomain.
‡‡‡‡Vineland Adaptive Behaviour Scales, Third Edition, Expressive and Receptive subdomain scaled scores.28
§§§§Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition.73
¶¶¶¶Universal Non-verbal Intelligence Test, Second Edition.74
-, not assessed; FSIQ, Full-Scale Intelligence Quotient; MR, matrix reasoning; N, no; PRI, perceptual reasoning index; Y, yes.