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We recently described a new neurodevelopmental syndrome (TAF1/MRXS33 intellectual disability [ID] syndrome) (MIM# 300966) caused by pathogenic variants involving the X-linked gene TATA-box binding protein associated factor 1 (TAF1), which participates in RNA polymerase II transcription. The initial study reported 11 families, and the syndrome was defined as presenting early in life with hypotonia, facial dysmorphia, and developmental delay that evolved into ID and/or autism spectrum disorder. We have now identified an additional 27 families through a genotype-first approach. Familial segregation analysis, clinical phenotyping, and bioinformatics were capitalized on to assess potential variant pathogenicity, and 450 |

Pathogenic variants account for 4 to 41% of patients with intellectual disability (ID) or developmental delay (DD). In Sub-Saharan Africa, the prevalence of ID is thought to be higher, but data in Central Africa are limited to some case reports. In addition, clinical descriptions of some syndromes are not available for this population. This study aimed at providing an estimate for the fraction of ID/DD for which an underlying etiological genetic cause may be elucidated and provide insights into their clinical presentation in special institutions in a Central African country. A total of 127 patients (33 females and 94 males, mean age 10.03 ± 4.68 years), were recruited from six institutions across Kinshasa. A clinical diagnosis was achieved in 44 but molecular confirmation was achieved in 21 of the 22 patients with expected genetic defect (95% clinical sensitivity). Identified diseases included Down syndrome (15%), submicroscopic copy number variants (9%), aminoacylase deficiency (0.8%), Partington syndrome in one patient (0.8%) and his similarly affected brother, X-linked syndromic Mental Retardation type 33 (0.8%), and two conditions without clear underlying molecular genetic etiologies (Oculo-Auriculo-Vertebral and Amniotic Bands Sequence). We have shown that genetic etiologies, similar to those reported in Caucasian subjects, are a common etiologic cause of ID in African patients from Africa. We have confirmed the diagnostic utility of clinical characterization prior to genetic testing. Finally, our clinical descriptions provide insights into the presentation of these genetic diseases in African patients.

Xia‐Gibbs syndrome (XGS) is a very rare genetic condition. The clinical spectrum is very broad and variable. The phenotype and evolution in a Congolese boy with XGS have been reported. At 6 years he had speech delay, drooling, marked hyperactivity, attention deficit, aggressive behavior, and intellectual disability. Dysmorphological evaluation revealed strabismus, mild unilateral ptosis, uplifted ear lobes, flat philtrum, thin upper lip vermillion, high arched palate, and flat feet. Patient‐only whole exome sequencing identified a known pathogenic frameshift variant in the AHDC1 gene [NM_001029882.3(AHDC1):c.1122dupC;(p.Gly375ArgfsTer3)]. The clinical follow‐up revealed the deterioration of his fine motor skills and significant cerebellar phenotype including tremor, pes cavus, and gait instability at the age of 12 years. This patient was compared with three previously reported patients with the same variant but did not identify a consistent pattern in the evolution of symptoms with age.

Background Information about the association with alpha thalassemia in sickle cell patients is unknown in the Democratic Republic of Congo. There is very little data on the alpha thalassemia in patients suffering from sickle cell anemia in Central Africa, and their consequences on the clinical expression of the disease. Methods A cross‐sectional study was conducted in 106 sickle cell patients living in the country's capital Kinshasa. The diagnosis of sickle cell anemia was confirmed with a molecular test using PCR‐RFLP (restriction fragment length polymorphism) technique. The diagnosis of thalassemia was performed by the technique of multiplex ligation dependent probe amplification. Results The mean age of our patients was 22.4±13.6 years. The α3.7 heterozygous deletion, the α3.7 homozygous deletion and the α3.7 triplication were respectively encountered in 23.6%, 25.5% , and 11.3% of patients. Patients with normal αα/αα genotype represented 39.6% of the study population. The average of severe vaso‐occlusive crises, the rates of blood transfusions per year, the rate of osteonecrosis, cholelithiasis and leg ulcers were significantly lower in the group of patients with α3.7 homozygous deletion and α3.7 triplication. Conclusion The prevalence of α3.7 triplication was higher in sickle cell patients in the Democratic Republic of Congo than in worldwide series. The α3.7 triplication and α3.7 homozygous deletion were associated with less severe forms of the Sickle cell anemia in Congolese patients. These results showed the need to investigate systematically the alpha‐globin gene mutations in sickle cell population in Central Africa.

FHb and alpha-thal are two genetic factors that modulate the clinical expression of sickle cell disease. Objective: to determine the beneficial role of FHb and alpha-thal on fetal and maternal morbidity during pregnancy in sickle cell patients. This is a documentary and analytical study that included 960 deliveries of homozygous sickle cell patients. The deliveries were divided into three genotype subgroups: Hb-SS / alpha-thal, HbSS / HPFH and HbSS. The diagnosis of SCD and the quantification of FHb were performed by the capillary electrophoresis technique. The diagnosis of SCD has been confirmed by the molecular test. The diagnosis of alpha-thal was made by the multiplex ligation dependent probe amplification (MLPA) technique. Sickle cell pregnancies were followed according to the protocol of care in force in our service. The variables of interest were: hematological variables, sickle cell crises during pregnancy, maternal and fetal complications. Statistical analyzes were performed with SPSS 20.0 software. Means and standard deviations were compared with the Student's t and Annova tests. The value of p <0.05 was considered the significance level. The Hb-SS / alpha-thal and HbSS / HPFH genotypes were observed in 101 and 121 women respectively. Otherwise 758 women had the HbSS genotype. The morbidity related to sickle cell complications in the mother and fetus, were less frequent in the Hb-SS / alpha-thal and HbSS / HPFH groups. The statistical differences were statistically significant. This study showed a significant protective effect of alpa-thal and HPFH during pregnancy in sickle-cell pregnant women. FHb and alpha-thal are two genetic factors that modulate the clinical expression of sickle cell disease. Objective: to determine the beneficial role of FHb and alpha-thal on fetal and maternal morbidity during pregnancy in sickle cell patients. This is a documentary and analytical study that included 960 deliveries of homozygous sickle cell patients. The deliveries were divided into three genotype subgroups: Hb-SS / alpha-thal, HbSS / HPFH and HbSS. The diagnosis of SCD and the quantification of FHb were performed by the capillary electrophoresis technique. The diagnosis of SCD has been confirmed by the molecular test. The diagnosis of alpha-thal was made by the multiplex ligation dependent probe amplification (MLPA) technique. Sickle cell pregnancies were followed according to the protocol of care in force in our service. The variables of interest were: hematological variables, sickle cell crises during pregnancy, maternal and fetal complications. Statistical analyzes were performed with SPSS 20.0 software. Means and standard deviations were compared with the Student's t and Annova tests. The value of p <0.05 was considered the significance level. The Hb-SS / alpha-thal and HbSS / HPFH genotypes were observed in 101 and 121 women respectively. Otherwise 758 women had the HbSS genotype. The morbidity related to sickle cell complications in the mother and fetus, were less frequent in the Hb-SS / alpha-thal and HbSS / HPFH groups. The statistical differences were statistically significant. This study showed a significant protective effect of alpa-thal and HPFH during pregnancy in sickle-cell pregnant women.

Screening for fragile X syndrome (FXS) is essential in children with developmental delay or intellectual disability (ID). In addition, using clinical screening checklists remains of high interest in resource-limited settings. We aimed to gain insight into the prevalence of FXS and the distribution of CGG alleles and to evaluate the usefulness of three checklists in specialized institutions in Kinshasa, DR Congo. We recruited 80 males and 25 females from six specialized institutions in Kinshasa and administered a questionnaire comprising items from the following FXS checklists: Hagerman, Maes, and Guruju. FMR1 CGG repeats were assessed for every patient. About 37% of patients were referable for FX testing based on Hagerman's checklist, 35% for Maes', and 43.80% for Guruju's, but none of them was molecularly confirmed to have FXS. Thus, specificities were 62.86, 64.76, and 56.5%, respectively, for Hagerman, Maes, and Guruju, respectively. The mean CGG allele size was 28.55 ± 2.83 (ranges, 17-48). The 29 CGG was the most frequent allele (24.61%). Thus, existing checklists should not be automatically applied to Congolese patients without adjustments. The distribution of CGG repeats and the number of CGG alleles are similar to other African studies.

Background Sickle cell anemia (SCA) is a monogenic hemoglobinopathy associated with severe acute and chronic complications, with the highest incidence worldwide in Sub-Saharan Africa. The wide variability in clinical manifestations suggest that a uniform response to hydroxurea may not be attained. In view of a potential treatment with hydroxyurea (HU), we assessed the variability of clinical and hematological manifestations in a cohort of adults with SCA in Kinshasa, capital of the DR Congo in Central Africa. Methods A cross-sectional study was conducted in a hospital dedicated to SCA management in Kinshasa. Clinical history of patients was recorded, a complete physical examination performed. The diagnosis was confirmed by means of DNA analysis. A full blood count and hemolysis markers were measured. The severity of the disease was evaluated by means of a previously reported score. Results The study group consisted of 166 genetically confirmed SCA patients. The SCA severity was mild in 28.9%, moderate in 64.5% and severe in 6.6%. The disease severity score increased with patient’s age (p ≤ 0.001). The severity was higher in males compared to females (p = 0.012). In males, the severity score was correlated with the presence of priapism (p = 0.045), a manifestation not previously incorporated in the severity score. The severity score was inversely correlated with the fetal hemoglobin (HbF) rate (p = 0.005). Malnutrition (BMI <18.5 kg/m2) was present in 47% of patients and was related to the male sex, hip disease (aOR 3.11; p = 0.019) and severe phenotype (aOR 3.53; p = 0.012). Leg ulcers were more frequent in males than in females (p = 0.001; OR 24.3) and were correlated with the number of days of hospitalization (p = 0.029). Hip disease was related to the increasing age (p = 0.008). Conclusion In this selected, hospital-based populations of adults with SCA, severe disease was rare, which may be due to survival bias. However, two thirds had moderate severity of the disease, mostly with a low HbF, and they may benefit from HU treatment. In the Central-African setting the separation between vaso-occlusive and hyperhemolytic sub-phenotypes was not applicable.