Table 2. Summary of the neck muscle phenotype observed in Tbx1- and Pax3-null fetuses.
| Tbx1-null | Pax3-null | |
|---|---|---|
|
Branchiomeric muscles (Mef2c-AHF/Islet1/Mesp1 lineage)
Mylohyoid Digastric muscles Intrinsic laryngeal muscles Esophagus striated muscle Sternocleidomastoid Acromiotrapezius |
+/- +/- − − +/- − |
++ ++ + ++ + + |
|
Anterior-most somite muscles (Mesp1/Pax3 lineage)
Epaxial musculature Longus capitis Longus colli Infrahyoid muscles Tongue muscles* |
++ +/- − − + |
+ ++ ++ +/- + |
|
More posterior somite muscles (Pax3 lineage)
Scapular muscles Pectoralis |
++ ++ |
− − |
++,normal; +, altered morphology; +/-, affected; -, severely affected or undetectable.
*Including intrinsic and extrinsic tongue muscles of somitic origin.