Differential Diagnosis
The differential diagnosis of congenital mirror movements (CMM) from mirror movements of other causes is mainly theoretic, as the findings in CMM are distinctive, isolated, and easily recognized. Physiologic mirror movements. The intensity of the mirror movements and their persistence after age seven years clearly differentiate pathologic from physiologic mirror movements. Mild physiologic mirror movements are frequent in normally developing young children. They usually disappear completely before age seven years and tend to recur gradually in old age . Syndromes with early-onset (congenital) mirror movements. Early-onset mirror movements are not always isolated; they may be a component of complex syndromes and congenital hemiplegia (the most common form of cerebral palsy) . Although the clinical characteristics of mirror movements have been less comprehensively investigated in these conditions, they resemble those of CMM. In practice, differential diagnosis of CMM is rarely an issue, as the associated findings are generally more significant. When the diagnosis is in doubt, brain and cervical MRI may be considered in children or adolescents with mirror movements. Table 2. Syndromes with Early-Onset Mirror Movements
Disorder | Gene(s) | MOI | Mirror Movements | Other Features |
|---|
ANOS1 Kallmann syndrome (KS) (See Isolated GnRH Deficiency.) | ANOS1 (KAL1) | XL | MM in persons w/KS is almost always linked to ANOS11 (ANOS1-KS accounts for ~5%-10% of isolated GnRH deficiency).; Prevalence of MM in KAL1-KS is 75%.1 | Hyposmia hypogonadotropic hypogonadism |
Joubert syndrome | ≥34 genes | ARXL2 | CMM is observed in some affected persons.3 | Hypoplasia of cerebellar vermis w/characteristic neuroradiologic molar tooth sign variable accompanying neurologic symptoms Klippel-Feil syndrome (KFS) (OMIM PS118100)4 |
MYO18B | ADAR | MM is present in minority of persons w/KFS (MM is likely linked to cervicomedullary neuroschisis). | Congenital fusion of cervical vertebrae | — |
Typical phenotype incl low posterior hairline, short neck, amplitude of neck movements Moebius syndrome (OMIM 157900) | Unknown | AD | MM is only occasionally reported.5 | Minimum criteria are congenital, non-progressive facial weakness in assoc w/limited abduction of 1 or both eyes. |
Nevoid basal cell carcinoma syndrome(Gorlin syndrome) | PTCH1(PTCH2)6SUFU | AD | MM reported in 1 person7 | Multiple basal cell carcinomas, jaw keratocysts, skeletal malformations |
Seckel syndrome(OMIM PS210600) | ATRCPAP (CENPJ)CEP152CEP63DNA2NINNSMCE2RBBP8TRAIP | AR | 1 reported person w/MM8 | Primary microcephaly, intellectual disability, often prenatal-onset growth restriction |
Wildervanck syndrome (OMIM 314600) | Unknown | XL? | 1 reported person w/MM9 | Klippel-Feil syndrome w/congenital perceptive deafness Duane syndrome10; Affected persons are almost exclusively female. AD =... |
Source: GeneReviews — "Congenital Mirror Movements"
