Adducted Thumbs Syndrome

Stiff facies, open mouth, high arched palate with cleft. Craniostenosis and microcephaly. Swallowing difficulties and generalized myopathic hypotonia. Respiratory insufficiency that generally leads to death in early infancy.

Approximately 10 cases have been reported. Inheritance seems to be autosomal recessive.

Dysmyelination characterized by excessive myelin-dependent gliosis, myelin solubilization, and transient formation of phospholipid-containing plaques on the brain's surface.

Clinical features and absence of extension of the thumb during the Moro reflex.

Typical features are craniostenosis, microcephaly, large occiput, mental retardation, seizures, external ophthalmoplegia, myopathic stiff facies, low-set and large, malrotated ears, open mouth, microgenia, abnormal temporomandibular joints (anomaly of the processus condylaris and mandibulares), high arched palate with cleft, and velopharyngeal insufficiency are common findings. Swallowing difficulties (absent gag reflex) and generalized myopathic hypotonia are typical. Laryngomalacia, recurrent pneumonias, and pectus excavatum have been described in the majority of patients. The most characteristic sign is flexion and adduction of the thumbs with arthrogryposis of elbows, wrists, and knees. Respiratory insufficiency is mainly caused by the generalized myopathic hypotonia and the main reason for the poor prognosis with death in early infancy (only one patient has survived the first year of life). Muscle biopsy reveals unspecific signs of congenital myopathy (i.e., wide variation in the diameter of muscle fibers, normal distribution of type I and II fibers, increased number of centrally located nuclei, increased interstitial tissue, lack of signs of denervation).

Obtain a history of developmental milestones, muscular hypotonia, recent chest infections, and swallowing difficulties. Assess respiratory function and obtain chest radiograph. Arterial blood gas analysis may be helpful under certain circumstances. Postoperative mechanical ventilation is likely given the poor muscle function and the associated respiratory problems (pneumonia, laryngomalacia).

Although difficult airway management would be expected given the facial anomalies described, no tracheal intubation problems have been reported in these children. Arthrogryposis may make vascular access and positioning difficult. Respiratory insufficiency likely will require intermittent positive pressure ventilation (IPPV) postoperatively.

No data are available; however, avoiding depolarizing agents in patients with congenital myopathies is advisable.

MASA Syndrome: Syndrome characterized by acrocephaly, brachycephaly, flat occiput, and maxillary hypoplasia. The mouth is small and the upper lip is thin. Muscular hypertrophy of the legs and subluxation of the hip.

Arthrogryposis: Spectrum of different syndromes characterized by persistent multiple limb contractures. Often associated with pharyngeal, cardiac, urinary, and gastric abnormalities. Often midline dysraphism abnormalities.

Christian Syndrome I (Christian-Andrews-Conneally-Muller Syndrome): Adducted thumbs syndrome with craniosynostosis, arthrogryposis, and cleft palate. Microcephaly, prominent occiput, hypertelorism, antimongoloid palpebral fissures, ophthalmoplegia, abnormal ear placement, and bifid uvula. Autosomal recessive.

Freeman-Sheldon Syndrome (FSS): Genetic malformative disorder characterized by microstomia, flat midface with a small pinched mouth mimicking whistling, clubfoot, contracted muscles of the joints of the fingers, and hands malformations.

Congenital Clasped Thumbs: Extremely rare disorder that is inherited in either an autosomal dominant or an X-gonosomal manner. The congenitally clasped thumbs most likely are secondary to atrophy or absence of the abductor and extensor pollicis muscles and/or tendons. Ulnar deviation of the hands with flexed digits, kyphoscoliosis, clubfoot, generalized muscular hypotonia, and muscular hypotrophy are common findings.