3. Discussion
Cerebrotendinous xanthomatosis is a rare autosomal recessive genetic disorder in which cholesterol cannot be converted into bile acids due to mutations in the CY27A1 gene that encodes the mitochondrial enzyme sterol 27-hydroxylase 3. Half of the mutations in CYP27A1 have been detected in exons 6–8, 16% in exon 2, and 14% in exon 4 10,11. The mean age at onset of clinical manifestations has been reported 19 years, but most patients are diagnosed late (about 35 years) 12. In our case, the patient had developmental delays in mental functioning and speech with neuropsychiatric disorders in childhood. In terms of clinical symptoms, patients with CTX often manifest non-neurological and neurological symptoms such as chronic diarrhea, cataracts, tendon xanthomas, ataxia, corticospinal tract involvement, and mental disorder. The initial presentation of non-neurological symptoms in our patient was a cataract that was revealed at the age of 5 years. In this patient, a CYP27A1 mutation was identified in exon 3. The characteristic brain MRI findings are T2/FLAIR hyperintensities in the bilateral dentate nuclei, adjacent cerebellar white matter, basal ganglia, spinal cord, and periventricular white matter as well as cerebellar atrophy. Our patient had T2/FLAIR hyperintensities in the bilateral dentate nuclei, white matter alternations, and cerebellar atrophy 13–15. One of the symptoms in our case was infertility, which was not reported in previous studies. The cause of infertility in this patient was non-obstructive azoospermia due to a lack of spermatogenesis in the testicles. The sex hormones, prolactin, and testosterone levels were normal. Co-occurrence of azoospermia in CTX patients may be due to the accumulation of cholesterol in the scrotum sac affecting spermatogenesis and the function of the male reproductive system. Cholesterol has been revealed to cause a reduction in sperm kinetics and has negative effects on Leydig and Sertoli cells secretory capacity in rabbits. Previous studies found that changed lipid metabolism in seminal plasma plays a role in male infertility 16–18. Accumulation of cholesterol in tissues is one of the obvious symptoms of CTX, but the resultant functional abnormalities are unknown. The relationship between infertility and cholesterol should be further investigated since it has not been addressed so far.