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Rationale: Mutations of connector enhancer of kinase suppressor of Ras-2 (CNKSR2) gene were identified as the cause of Houge type of X-linked syndromic mental retardation. The mutations of CNKSR2 gene are rare, we reporta patient carrying a novel nonsense mutation of CNKSR2,c.625C > T(p.Gln209∗) and review the clinical features and mutations of CNKSR2 gene for this rare condition considering previous literature. Patient concerns: We report a case of a 7-year and 5-month-old Chinese patient with clinical symptoms of intellectual disability, language defect, epilepsy and hyperactivity. Genetic study revealed a novel nonsense variant of CNKSR2, which has not been reported yet. Diagnosis: According to clinical manifestations, genetic pattern and ACMG classification of mutation site as Class 1-cause disease, the patient was diagnosed as Houge type of X-linked syndromic mental retardation caused by CNKSR2 gene mutation. Interventions: The patient was administrated with a gradual titration of valproic acid (VPA). Outcomes: On administration of valproic acid, he had no further seizures. Lessons: This is the first time to report a nonsense variant in CNKSR2, c.625C > T(p.Gln209∗), this finding could expand the spectrum of CNKSR2 mutations and might also support the further study of Houge type of X-linked syndromic mental retardation.

Rationale: Mutations of the MORC2 gene have most commonly been associated with autosomal-dominant Charcot–Marie–Tooth disease type 2Z (CMT 2Z), while the impact of MORC2 mutations in CMT 2Z on neuronal biology and their phenotypic consequences in patients remain to be clarified. Patient concerns: We reported a 27-month-old child with a developmental lag of more than 1 year. He had progressive fatigue for 4 months, accompanied by dysphagia, choking while eating, and progressive aggravation. A genetic study revealed a de novo variant of MORC2, which has not yet been reported. Diagnosis: According to the child's clinical manifestations, genetic pattern, and American College of Medical Genetics and Genomics pathogenicity analysis, the patient was diagnosed with CMT 2Z caused by MORC2 gene mutation. Interventions: Mitochondrial cocktail therapy (arginine, vitamin B1 tablets, vitamin B2 tablets, coenzyme Q10 capsules, L-carnitine oral liquid, idebenone tablets, etc) was given. Outcomes: Mitochondrial cocktail therapy did not significantly improve the child's condition, head magnetic resonance imaging lesions were not significantly improved at outpatient follow-up more than 1 month later, and the lesions were basically unchanged. Lessons: The clinical manifestations of the disease were similar to those of Leigh syndrome, and they were not significantly improved by cocktail therapy. This site has not been reported in the literature domestically or abroad, and the pathogenesis of CMT 2Z caused by this site mutation is indeed not related to mitochondrial dysfunction. Our study is helpful for clinicians with regard to the differential diagnosis of Leigh syndrome and CMT 2Z and improvement of clinicians’ understanding of CMT 2Z disease.

The distribution characteristics of ABO and RhD blood groups in the world were different and the data were limited. The aim was to investigate the distribution characteristics of ABO and RhD blood groups in Chongqing, and to provide scientific-effective data for a more reasonable blood collection program. We retrospectively analyzed 795 698 blood donors who had donated blood from 2014 to 2019 at the Chongqing Blood Center. The data on ABO and RhD blood groups were extracted based on blood management system. We used percentages to describe the extraction of data on blood donors by gender, age, and nationality. The data on the distribution of ABO (A, B, AB and O) and RhD (RhD-Positive and RhD-Negative) blood groups were reported also in percentages. Of those, 427 516 (53.73%) were males and 368 182 (46.27%) were females. Among all the blood donors, 321 916 (40.46%) were under the age of 25, followed by 26-35 years age group (22.65%), 36-45 years age group (18.95%), 46-55 years age group (16.98%) and 56-60 years age group (0.96%). There were 755439 (94.94%) of the blood donors who were of the Han nationality. The distribution of blood groups O, A, B and AB were 35.54%, 31.90%, 24.14% and 8.42%, respectively. The distributions of RhD-Negative group was found in 4362 (0.55%) blood donors. The distribution characteristics of the ABO and RhD blood group should be considered when improving blood collection program in Chongqing.