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Purpose of Review: We review the congenital and genetic diagnoses that are currently included in the congenital cranial dysinnervation disorders (CCDDs)., Recent Findings: Recent literature contains new genotypic and phenotypic descriptions of Duane retraction syndrome, Moebius syndrome, and other CCDDs. New genes which when mutated can result in CCDD have been identified, permitting a better understanding of associated phenotypes. More information is available regarding neurodevelopmental and clinical effects of various gene mutations associated with individual CCDDs. For certain CCDDs, the phenotype of a particular individual may not completely predict the genotype, and conversely, the genotype may not always predict the phenotype., Summary: The CCDD concept has focused attention on specific congenital disturbances of human ocular motility and on the fact that these disorders are typically neurogenic in origin. The past decade has seen rapid evolution within this field with the last 2 years yielding additional information about existing diagnoses, genes, and phenotypes that may result in better classification of these disorders and new genotype-phenotype correlations in the future.

We describe the clinical characteristics of 3 siblings from 1 family with congenital myasthenic syndrome due to homozygous mutations of the gene coding for the epsilon subunit of the acetylcholine receptor (CHRNE). Onset of symptoms occurred in the first few months of life with ptosis, restricted ocular motility, mild proximal weakness, and difficulty swallowing. Multiple hospital admissions were required due to recurrent pulmonary infections. There was no decremental conduction on repetitive nerve stimulation, but jitter was increased on single fiber electromyographic. Since early childhood, our patients have done well without pulmonary or bulbar symptoms and with partial improvement on pyridostigmine therapy. Response of ptosis to diagnostic ice pack test was striking. Although these siblings have a clinical history and examination findings typical of homozygous CHRNE mutations, the clinical presentation of congenital myasthenia subtypes is variable, and accurate genotyping is essential in choosing the appropriate treatment.

In 1707, Valsalva reported a patient with unilateral cerebral hemorrhage associated with weakness on the contralateral side of the body, and Morgagni in De Sedibus subsequently referred to this crossed relationship of brain to body as the Valsalva doctrine. Since then, decussation of corticospinal tracts and many other neural pathways within the CNS has become so deeply embedded in neurologic thinking that exceptions may not be considered and therefore may be overlooked. Several uncommon clinical events that result in paralysis ipsilateral to brain injury highlight nuances of normal human neuroanatomy and neuropathology. More recently, exceptions to the Valsalva doctrine have been documented in 2 autosomal recessive genetic conditions: horizontal gaze palsy and progressive scoliosis and Joubert syndrome. In these syndromes, corticospinal tracts and certain other brainstem neural pathways do not decussate normally, and knowledge of the responsible genes for the first time teaches us something about the molecular mechanisms that direct the corticospinal tracts across the midline. However, we still do not understand why decussation occurs.

Background: The Bosley-Salih-Alorainy syndrome (BSAS) variant of the congenital human HOXA1 syndrome results from autosomal recessive truncating HOXA1 mutations. We describe the currently recognized spectrum of ocular motility, inner ear malformations, cerebrovascular anomalies, and cognitive function., Methods: We examined nine affected individuals from five consanguineous Saudi Arabian families, all of whom harbored the same I75-I76insG homozygous mutation in the HOXA1 gene. Patients underwent complete neurologic, neuro-ophthalmologic, orthoptic, and neuropsychological examinations. Six individuals had CT, and six had MRI of the head., Results: All nine individuals had bilateral Duane retraction syndrome (DRS) type 3, but extent of abduction and adduction varied between eyes and individuals. Eight patients were deaf with the common cavity deformity of the inner ear, while one patient had normal hearing and skull base development. Six had delayed motor milestones, and two had cognitive and behavioral abnormalities meeting Diagnostic and Statistical Manual of Mental Disorders-IV criteria for autism spectrum disorder. MRI of the orbits, extraocular muscles, brainstem, and supratentorial brain appeared normal. All six appropriately studied patients had cerebrovascular malformations ranging from unilateral internal carotid artery hypoplasia to bilateral agenesis., Conclusions: This report extends the Bosley-Salih-Alorainy syndrome phenotype and documents the clinical variability resulting from identical HOXA1 mutations within an isolated ethnic population. Similarities between this syndrome and thalidomide embryopathy suggest that the teratogenic effects of early thalidomide exposure in humans may be due to interaction with the HOX cascade.

The authors sequenced the entire mitochondrial DNA coding region in a group of 19 patients with non-arteritic anterior ischemic optic neuropathy (NAION) and in 100 controls. Synonymous and nonsynonymous nucleotide changes were more common in NAION patients (p < 0.001). Twelve of these (11 novel) were potentially pathologic, nine of which altered moderately or highly conserved amino acids in the functional domain of the affected protein. Mitochondrial malfunction may be a risk factor for NAION.