Carey-Fineman-Ziter syndrome is a congenital myopathy associated with mutations in the MYMK gene. It is clinically defined by the combination of hypotonia, Moebius-Robin sequence, facial anomalies and motor delay. Historically it was considered a brainstem dysgenesis syndrome. We provide detailed information of a Spanish boy with compound heterozygous variants in MYMK gene. A muscle biopsy performed as a toddler only disclosed minimal changes, but muscle MRI showed severe fatty infiltration of gluteus muscles and to a lesser extent in adductors magnus, sartorius and soleus muscles. Clinical course is fairly static, but the identification of new well characterized genetic cases will help to delineate the complete phenotype.
Keywords: Carey-Fineman-Ziter syndrome; congenital myopathy; facial weakness; myomaker (MYMK gene).