An inherited syndrome with ataxia, corneal dystrophy, and orthopedic anomalies.
Der Kaloustian-Jarudi-Khoury Syndrome; Familial Spinocerebellar Degeneration and Corneal Dystrophy; Corneal Dystrophy with Spinocerebellar Degeneration.
It has only been described in two sisters of healthy, but consanguineous parents.
Autosomal recessive inheritance has been suggested.
Based on the clinical findings and family history.
Onset of the disease is in the second year of life, when bilateral corneal opacifications of the corneas (which eventually will result in severe visual impairment) and slowly progressive cerebellar anomalies with variable spinocerebellar (dorsal column and upper motor neuron) involvement begin. The patients may have mild mental delay. In addition to the ocular findings (ptosis, corneal edema, pannus, and dystrophy with corneal clouding and visual loss requiring penetrating keratoplasty), the disorder may also be associated with anomalies of the face (triangular shape, micrognathia, low-set, and posteriorly rotated ears), the nervous system (abnormal electroencephalogram, spinocerebellar degeneration, ataxia, tremors of head (constant nodding), hand and trunk, hemiparesis, muscular hypertonia, and spasticity), and the musculoskeletal system (cervical hyperlordosis, lumbar scoliosis, dislocation of the hips). Histologic anomalies of muscles were described as random variations in muscle fiber size and rounding of muscle fibers. Electron microscopy revealed subsarcolemmal mitochondrial aggregates intermixed with lysosomes, lipid droplets, and giant mitochondria with dense cristae and filamentous inclusions. A sural nerve biopsy showed increased connective tissue between fibers and a paucity of myelinated nerve fibers with signs of myelin breakdown. Many nerve fibers were surrounded by concentric cuffs of circumferential processes of Schwann cells in an onion bulb-like pattern. Nerve condition studies may reveal delayed motor conduction.
Precautions before anesthesia
The reported facial anomalies could suggest difficult airway management; however, judging from the photographs in the original paper, the features appear to be mild and would not expected to cause problems, but of course, clinical evaluation is still required. Developmental delay and impaired vision may cause agitation and stress in the perioperative period, thus anxiolytic and sedative premedication and/or presence of a parent (or primary caregiver) for induction of anesthesia may be beneficial.
Careful perioperative handling and positioning is advised to prevent dislocations, pressure sores, and/or nerve injuries. Regional anesthesia is not contraindicated per se, but could be difficult due to spine deformities. In addition, spinocerebellar degeneration likely precludes most anesthetists from performing a central neuraxial blockade, although no evidence exists to support these concerns. Intraoperative eye protection should include ointment and tape to keep the eyes shut.
Upper motor neuron involvement could result in exaggerated hyperkalemia following succinylcholine administration, hence it should best be avoided.