Akademik Veri Yönetim Sistemi
6. Uluslararası Katılımlı Erciyes Tıp Tıbbi Genetik Kongresi,, Kayseri, Türkiye, 16 - 18 Eylül 2021, ss.43
Cerebral creatine deficiency syndrome 1 (CCDS1, OMIM#300352) is an X-linked inherited disease characterized
by mental retardation, speech impairment, behavioral abnormalities, and seizures. This disease is caused by a
mutation in the SLC6A8 gene. Approximately 150 patients have been reported in the literature to date. A 12-
year-old boy, the first child of a healthy consanguineous couple, was consulted to our clinic with epilepsy,
mental retardation and chorea-like movement disorder. On examination, the patient had microcephaly, global
developmental delay, moderate-severe intellectual disability and autistic behaviors. MRI of the brain showed
corpus callosum hypoplasia. After evaluating the laboratory results of the patient, hypouricemia and low
creatinine in the plasma were noted.
Whole exome sequencing (WES) was performed from the blood sample of the patient. Reportable variants were
classified according to the criteria of the American College of Medical Genetics (ACMG). Disease-specific
information for variants was obtained using the ClinVar database.
WES analysis detected a 3-base hemizygous deletion in the SLC6A8 gene which was consistent with the
patient's clinical findings. The deletion site was in a critical and well-defined functional region. The variant was
classified as likely pathogenic. In addition, a previously reported homozygous pathogenic variant in the PROK2
gene and a homozygous pathogenic variant in the XDH gene were identified. These results were thought to be
compatible with the patient's clinical findings. Genetic counseling was given to the family about the disease. In
this study, 3 rare disease-causing mutations were reported in a patient.
Keywords: CCDS1, Intellectual disability, Neurodevelopmental disorder, SLC6A8