Bilateral patellar dislocation associated with alpha-mannosidase deficiency

Familial association and epidemilogical factors as risk factors for developing first time and recurrent patella dislocation: a systematic review and best knowledge synthesis of present literature

PURPOSE

The aim of our study was to perform a systematic review and best knowledge synthesis of the present literature concerning the familial association and epidemiological factors as risk factors for developing first-time and recurrent patella dislocation.

METHODS

The study was conducted according to the PRISMA guidelines and registered in PROSPERO. EMBASE and PubMed were systematically searched on the 5th of May 2022. Studies investigating participants with genetic and epidemiological risk factors for the first time as well as recurrent patella dislocation were included. The records were screened, and data were extracted independently by two researchers supervised by a third independent assessor.

RESULTS

A total of 6,649 records were screened, and 67 studies were included. Familial association was described as a risk factor for patella dislocation in 17 studies. One study found that participants with a family history of patella dislocation had a 3.7 higher risk for patella dislocation in the contralateral asymptomatic knee, and another study found a family history of PD in 9% of 74 participants. Eleven studies found an accumulation of patella dislocation across generations in specific families. Additionally, a range of genetic syndromes was associated with patella dislocation. Young age is a well-investigated risk factor for patella dislocation, but the results are inconsistent. Only five and eight studies investigated skeletal immaturity and gender as risk factors for patella dislocation, respectively.

CONCLUSION

There may be a familial association with patella dislocation, but further investigation is necessary to determine the strength and etiology of the association. There is weak evidence that epidemiological risk factors, such as age, skeletal immaturity, gender, and BMI are risk factors for patella dislocation.

LEVEL OF EVIDENCE

IV.

Mucopolysaccharidosis-like phenotype in feline Sandhoff disease and partial correction after AAV gene therapy

Sandhoff disease (SD) is a fatal neurodegenerative disease caused by a mutation in the enzyme β-N-acetylhexosaminidase. Children with infantile onset SD develop seizures, loss of motor tone and swallowing problems, eventually reaching a vegetative state with death typically by 4years of age. Other symptoms include vertebral gibbus and cardiac abnormalities strikingly similar to those of the mucopolysaccharidoses. Isolated fibroblasts from SD patients have impaired catabolism of glycosaminoglycans (GAGs). To evaluate mucopolysaccharidosis-like features of the feline SD model, we utilized radiography, MRI, echocardiography, histopathology and GAG quantification of both central nervous system and peripheral tissues/fluids. The feline SD model exhibits cardiac valvular and structural abnormalities, skeletal changes and spinal cord compression that are consistent with accumulation of GAGs, but are much less prominent than the severe neurologic disease that defines the humane endpoint (4.5±0.5months). Sixteen weeks after intracranial AAV gene therapy, GAG storage was cleared in the SD cat cerebral cortex and liver, but not in the heart, lung, skeletal muscle, kidney, spleen, pancreas, small intestine, skin, or urine. GAG storage worsens with time and therefore may become a significant source of pathology in humans whose lives are substantially lengthened by gene therapy or other novel treatments for the primary, neurologic disease.

Alpha-mannosidosis

Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be treated frequently. Otolaryngological treatment of fluid in the middle ear is often required and use of hearing aids is invariably required. Early educational intervention for development of social skills is needed and physiotherapy is important to improve bodily function. Orthopedic surgery may be necessary. The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age.