Compound heterozygous mutation of the SNX14 gene causes autosomal recessive spinocerebellar ataxia 20

Objective: The article aims to provide genetic counseling to a family with two children who were experiencing growth and developmental delays. Methods: Clinical information of the proband was collected. Peripheral blood was collected from core family members to identify the initial reason for growth and developmental delays by whole exome sequencing (WES) and Sanger sequencing. To ascertain the consequences of the newly discovered variants, details of the variants detected were analyzed by bioinformatic tools. Furthermore, we performed in vitro experimentation targeting SNX14 gene expression to confirm whether the variants could alter the expression of SNX14. Results: The proband had prenatal ultrasound findings that included flattened frontal bones, increased interocular distance, widened bilateral cerebral sulci, and shortened long bones, which resulted in subsequent postnatal developmental delays. The older sister also displayed growth developmental delays and poor muscle tone. WES identified compound heterozygous variants of c.712A>T (p.Arg238Ter) and .2744A>T (p.Gln915Leu) in the SNX14 gene in these two children. Both are novel missense variant that originates from the father and mother, respectively. Sanger sequencing confirmed this result. Following the guideline of the American College of Medical Genetics and Genomics (ACMG), the SNX14 c.712A>T (p.Arg238Ter) variant was predicted to be pathogenic (P), while the SNX14 c.2744A>T (p.Gln915Leu) variant was predicted to be a variant of uncertain significance (VUS). The structural analysis revealed that the c.2744A>T (p.Gln915Leu) variant may impact the stability of the SNX14 protein. In vitro experiments demonstrated that both variants reduced SNX14 expression. Conclusion: The SNX14 gene c.712A>T (p.Arg238Ter) and c.2744A>T (p.Gln915Leu) were identified as the genetic causes of growth and developmental delay in two affected children. This conclusion was based on the clinical presentations of the children, structural analysis of the mutant protein, and in vitro experimental validation. This discovery expands the range of SNX14 gene variants and provides a foundation for genetic counseling and guidance for future pregnancies in the affected children's families.

Growth status of children in well-baby outpatient clinics and related factors

AIM

The aim of this study was to determine the state of growth during follow-up of healthy children and the factors affecting growth.

MATERIAL AND METHODS

The patient cards of the infants who were born in 2002 and followed up in the well-baby outpatient clinic in Gazi University, Medical Faculty regularly for at least 18 months were examined retrospectively. Their sociodemographic properties including age, education level, occupation of the parents, if the mother was working, caretakers and gender, gestational week, birth weight, birth height and mode of nutrition (breastmilk, formula, cow's milk, period of feeding, etc.) and growth of the babies (month, percentile) were recorded. Number of siblings and ages of the siblings were also recorded and the children with and without growth problems were compared in terms of these properties.

RESULTS

It was found that 290 (39.3%) of 739 children who were followed up continued to grow up in the percentile in which they started (normal growth), 188 (25.4%) lost 2 or more percentiles in any month (growth retardation) and 261 (35.3%) lost less than 2 percentiles (decelerated growth). Deceleration/retardation in growth was observed most commonly in the 9(th) month. Deceleration in growth was found in the 6(th) month in 23.6% of the group with deceleration in growth, in the 9(th) month in 50.2%, in the 12(th) month in 15.8% and in the 18(th) month in 3.9%. Growth retardation was found in the 6(th) month in 35.8% of the group with growth retardation, in the 9(th) month in 38.0% and in the 18(th) month in 4.3%. It was found that receiving formula and presence of infection were the main risk factors in terms of deceleration of growth and unemployed mother, the lenght of the total time of breastfeeding and presence of infection were the main risk factors in terms of growth retardation.

CONCLUSIONS

This study shows the importance of follow-up of growth of children in outpatient clinics for healthy children. It was found that detailed examination and recording of non-organic causes is necessary in addition to investigation of pathological causes of growth retardation. Since it was observed that elimination of the defects determined and educating the family about nutrition and supporting growth had a positive impact on growth retardation, it was concluded that all children should be followed up regularly especially in the first years of life.