Wolfram Syndrome: Case series and review of the literature

doi:10.21203/rs.3.rs-2218670/v1

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Wolfram Syndrome: Case series and review of the literature

https://doi.org/10.21203/rs.3.rs-2218670/v1

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published 16 Nov, 2023

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Background:Wolfram syndrome is a rare autosomal recessive multisystem neurodegenerative disease, mainly with diabetes, optic atrophy, sensorineural deafness, and diabetes as the main features. Because of clinical phenotype heterogeneity, its misdiagnosed rate is high. However, early accurate diagnosis and comprehensive management is the key to improving the quality of life and prolonging life.

Results:This study reported 11 patients from 7 WS pedigrees with 10 mutation sites (c.1314_1317delCTTT, c.C529T, c.C529A, c.G2105A, c.C1885T, c.1859_1860del, c.G2020A, c.C529A, c.G2105A, c.G1393C) of the WFS1 gene.We further conducted expert department analysis to clarify the diagnosis and analyze the correlation between gene and phenotype.

Conclusions: We found that the genotype of the patients was closely related with the phenotype. And the genotype-phenotype correlation was analyzed combined with the clinical data of the patients, to provide the basis for the diagnosis and clinical management of the disease.

Wolfram Syndrome

WFS1 gene

Diabetic Mellitus

Genetic Testing

Wolfram syndrome(WS) is a rare autosomal recessive disorder caused by mutations in the WFS1 or CISD2 gene, with a global prevalence of one in 50 0,000 ^[1]. Patients often present with diabetes mellitus, optic atrophy, diabetes insipidus, sensorineural deafness, abnormal urinary tract, and neuropsychiatric disorders. Diabetes is often the first clinical symptom in children and adolescents. The average life of about 30 years.The clinical presentation of the disease varies widely, and the diagnosis is challenging. Due to the underlying genetic defect genes differ, Wolfram syndrome is divided into type 1 by genetic changes in WFS1 and CISD2 genes, respectively, with the former with more severe clinical manifestations and poor prognosis^[2], Because the disease involves multiple systemic organ systems, including eyes, ears and kidneys and the large age span of different clinical features appears, the condition is highly heterogeneous and the diagnosis is challenging.

Ethics statement

The study was reviewed and approved by the Hospital Ethics Committee (KY2022102801), and all study subjects or their guardians signed an informed consent. Phenotypic evaluation was completed through review of medical records and in-person examination by physicians who are co-investigators on the study.

Exome Sequencing And Variant Analysis

Mutation screening: Exons were captured by “Exome Research Panel v2.0 + Exome Research Panel v2.0 “ and the Illumina sequencing platform for high-throughput sequencing.

Gene data analysis: The sequencing data were aligned to the human genome by BWA(0.7.12-r1039) software, The mutation sites were annotated with dbSNP, Clinvar, ExAC, thousand human genome by Hannover ($ d a t e, 2015-06-17). Suspected pathogenic mutations were graded according to the ACMG (American Society of Medical Genetics and Genomics) genetic variant grading system. At the same time, software prediction and population database annotation were performed for unreported mutations or mutations with unclear clinical significance.

Verification of the suspected pathogenic mutation: After PCR of the target sequence of the suspected pathogenic mutation, it was verified by ABI3730 Sanger sequencing, and the sequencing results were verified by the DNASTAR subroutine SeqMan software.

Clinical presentation

All patients diagnosed with WS seen at a tertiary hospital in Xinjiang, China from 2016 to 2022 were included in these case series.11 cases were included, and 7 out of the 11 cases were male. The age at diagnosis of WS was from 8 to 30 years old. For a summary of the genealogy, see (Fig. 1).

Case 1

A 21-year-old female noticed gradual dry mouth, polyuria, and fatigue for the past 14 years. At the age of 7, because of fasting blood glucose was 28.0 mmol/L, She was diagnosed with "Type 1 diabetes mellitus" and was treated with insulin injection. At the age of 19, she developed a decrease in vision in both eyes. She was otherwise healthy and did not take any medications. Her parents denied consanguineous marriage and no diabetes in the family. She had a BMI of 19.5 kg / m2, an HbA1c rate of 9.8%, double hydronephrosis, bilateral ureteral dilatation, diabetic retinopathy, and optic nerve papillary atrophy in both eyes. The hearing examination was very normal. Diagnosis of WS was suspected and genetic testing suggested carrying the homozygous mutation of WFS1 c.1314_1317delCTTT,p.F438Lfs * 3, and the Sanger verification of the family members: both the parents and the elder brother carried a heterozygous mutation.

Case 2

14-year-old male noticed dry mouth, polyuria for the past 4 years, and slow growth for the past 3 years. At the age of 10, because of fasting blood glucose was 16.0 mmol/L, he was diagnosed with "type 1 diabetes mellitus" and was given treatment with insulin. At the age of 11, slow growth appeared, and his height was shorter than his peers. Vision loss, urinary frequency, and urinary incontinence in recent two years. His parents were consanguineous in marriage (Ⅱ4, Ⅱ5), and grandpa (Ⅰ1), grandma (Ⅰ2), uncle (Ⅱ1), and uncle (Ⅱ3) have diabetes. His BMI was 18.3 kg / m², HbA1c 14.9%, and hydronephrosis, bilateral ureal expansion. The indirect water deprivation test was negative, and the pituitary MRI suggested a pituitary microadenoma. In addition, there are refractive errors in his both eyes and sensorineural deafness in the right ear. A diagnosis of WS was suspected, and genetic testing indicated a homozygous mutation carrying WFS1 c.529C > T p. R177C, parents, second uncle, and grandmother carried heterozygous mutations, while the younger brother and sister were homozygous mutations, but no relevant clinical findings were found and were still in close follow-up.

Case 3

A 17-year-old male noticed thirst and polyuria for the past 14 years. At the age of 3 years old, he developed polyuria with a random blood glucose of 42.8 mmol/L. He was diagnosed with "type 1 diabetes, diabetic ketosis". At the age of 9 years old, his height was shorter than his peers, and his vision and hearing loss decreased at the age of 14 years. His parents were consanguineous in marriage (Ⅲ2、Ⅲ3), and grandpa (Ⅱ3), grandma (Ⅱ2), and aunt (Ⅲ6) have diabetes. Now he is 1.3m tall with a weight of 27 kg, HbA1c 10.6%, optic nerve atrophy, mild hydronephrosis in the left kidney, and expansion of the upper ureteric segment. Diagnosis of WS was suspected and genetic testing suggested carrying the homozygous mutation of WFS1 c.C529A p.R177S and exon8 c.G2105A p.G70, and his parents, brother, sister, grandma, grandpa, aunt, and uncle all carried homozygous or heterozygous mutations.

Case 4

A 17-year-old male noticed polydipsia and polyuria for the past 12 years, At the age of 15, he checked random blood glucose of 33.1mmol/L, and was diagnosed with "type 1 diabetes, diabetic ketosis", and was discharged after insulin treatment. In recent years, the patients repeatedly experienced palpitation, sweating, hunger, handshaking, and relief after eating. The parents denied consanguineous marriage and no diabetes in the family. Now he is 1.55m tall with a weight of 46 kg, HbA1c 10.6%, and mild water accumulation in both kidneys and ureter. Diagnosis of WS was suspected and genetic testing suggested carrying the homozygous mutation of WFS1 c.C1885T p.R629W, and both parents carried heterozygous mutations.

Case 5

A 30-year-old male noticed a gradual decrease in vision in both eyes for the past 16 years. At the age of 14, he was diagnosed with "optic atrophy", and 2 years later, he was diagnosed with "type 1 diabetes”, due to fasting blood glucose of 18.0mmol/L.His parents denied consanguineous marriage and his uncle (Ⅱ2) have diabetes, and two sisters (Ⅲ4、Ⅲ6) are also clearly diagnosed as WS. Fasting blood glucose 17.8mmol/L, 2 h postprandial blood glucose 20.28mmol/L, HbA1c 7.9%, fasting C peptide 2.25 ng/ml, 2 h C peptide 2.76 ng / ml and islet-related antibodies were negative. A diagnosis of WS was suspected, and genetic testing indicated a homozygous mutation carrying the WFS1 c.1859_1860del p. V620Gfs * 91, and c. G2020A p.G674R compound heterozygous mutation, while its parents and uncles carry heterozygous mutations, and both sisters carry compound heterozygous mutations.

Case 6

A 12-year-old male noticed thirst, drinking, polyuria, and wasting for the past 7 years. At the age of 5, he was diagnosed with type 1 diabetes, and blood glucose was unknown, and was discharged after insulin treatment. His patients were consanguineous in marriage (Ⅳ3、Ⅳ4)with diabetes, and his brother (V6) was also clearly diagnosed as WS. Now he is 1.4m tall with a weight of 32 kg, HbA1c 11.1%, optic nerve atrophy, and refractive error (both eyes). His brother is 8 years old, after a perfect examination, he was diagnosed with WS and given insulin injection treatment. Diagnosis of WS was suspected and genetic testing suggested carrying the homozygous mutation of WFS1 c.C529A p.R177S and c.G2105A p.G702D mutations, and both parents, aunt, and brother carried compound heterozygous mutations.

Case 7

A 19-year-old family noticed thirst, polydipsia, and polyuria 14 years ago. The local hospital diagnosed "type 1 diabetes" and has been given insulin injections until now. She had no menstruation.Her parents were consanguineous in marriage (Ⅲ3、Ⅲ4), and the younger brother (Ⅳ2) was also clearly diagnosed as WS. Now he is 1.23m tall with a weight of 25kg, and no secondary sexual characteristics. Relevant examination was low hypogonadism (LH 0.59IU / L FSH4.34IU/L E2 < 10.08Pg/ml)and central hypothyroidism (T4 FT411.02PMOL/L TSH3.8) .In addition, her anti-islet cell antibody is negative, severe hydronephrosis and ureteral dilatation. There were no significant hearing abnormalities or eye diseases. Her younger brother (Ⅳ2) was diagnosed with T1DM at the age of 10 due to abnormal blood glucose and was treated with insulin. he had cleft lip and palate, finger and toe development deformity. He also had severe hydronephrosis and low vision. Diagnosis of WS was suspected and genetic testing suggested carrying the homozygous mutation of WFS1 c.G1393C p.A465P, and her father carried the heterozygous mutation and has not retained the samples.

Genetic Analysis

This study reported 7 families with Wolfram syndrome, 11 patients, screened with a total of 10 mutations in the WFS1 gene screened. Among these, only c.G1393C showed a VUS mutation, and the rest were P / LP mutations(c.1314_1317delCTTT, c.C529T, c.C529A, c.G2105A, c.C1885T, c.1859_1860del and c.G2020A, c.C529A, c.G2105A)(Table 1).Among them,except for c.529C > T in family B,c.G2105A in family C, c.G2020A in family E, and c.G2105A in family F were reported (without functional verification), the rest mutation sites have not been reported and belong to new mutations.

Table 1

WFS1 mutations in 7 Wolfram syndrome families
Case	Exon	Nucleotide change	Amino acid change	Hom/Het	Type of mutation	ACMG	First description
A	8	c.1314_1317delCTTT	p.F438Lfs*3	Hom	Frameshift	LP(PVS1_Strong + PM2 + PP4)	Novel
B	5	c.C529T	p.R177C	Hom	Missense	LP(PM3_Supporting + PM1 + PM2 + PM5 + PP3)	[3]
C	8	c.C529A	p.R177S	Het	Missense	P(PM1 + PM2 + PM5 + PP1_Strong + PP3 + PP4)	Novel
C	8	c.G2105A	p.G702D	Het	Missense	P(PM3_Moderate + PM1 + PM2 + PM5 + PP1_Strong + PP3 + PP4)	[4–5]
D	8	c.C1885T	p.R629W	Hom	Missense	LP(PS4 + PM2 + PM3)	Novel
E	8	c.1859_1860del	p.V620Gfs*91	Het	Frameshift	P(PVS1_Strong + PM2 + PM3 + PP1_Strong + PP4)	Novel
E	8	c.G2020A	p.G674R	Het	Missense	P(PM3_Strong + PM1 + PM2 + PM5 + PP1_Strong + PP3 + PP4)	[6–7]
F	8	c.C529A	p.R177S	Het	Missense	LP(PM1 + PM2 + PM5 + PP1_Supporting + PP3 + PP4)	Novel
F	8	c.G2105A	p.G702D	Het	Missense	LP(PM3_Moderate + PM1 + PM2 + PM5 + PP1_Supporting + PP3 + PP4)	[8–9]
G	8	c.G1393C	p.A465P	Hom	Missense	VUS(PM2 + PM3_Supporting + PP4)	Novel
P = Pathogenic, LP = Likely Pathogenic,VUS = Uncertain significance

Wolfram syndrome is a rare autosomal recessive monogenic genetic syndrome. It is mainly characterized by childhood and adolescent onset-onset diabetes and progressive optic atrophy. The disease usually involves multisystem diseases, including diabetes insipidus (DI), diabetes mellitus (DM), visual atrophy (OA), and deafness (D), so it is also known as DIDMOAD. Some patients present with growth retardation, hydronephrosis, hypothyroidism, sleep disturbance, and neurological symptoms^[10]. The clinical course of WS is characterized by different symptoms in chronological order, with nonimmune insulin-dependent diabetes mellitus generally starting at the age of 6; optic atrophy occurring at around 11, diabetes insipidus usually occurring around 14, and sensorineural deafness gradually developing in late puberty ^[11].

The current study shows that the WFS1 gene is a key pathogenic gene of Wolfram syndrome, and the dysfunction or deletion of its encoded protein caused by the mutation of this gene is a major factor in the disease occurrence. 90% of WS patients are Wolfram syndrome type 1 (WS1) caused by mutations in the WFS1 gene^[12]. WFS1 protein includes 890 amino acids, and according to The Human Gene Mutation Database, a total of 464 mutations of different types of WFS1 gene were reported ^[13].In this study,rare double homozygous missense mutations of WFS1 base were found in family C and F probands, which altered protein Arg177Ser for GC528_529delinsTA, occurring at the protein N terminus of the cytoplasm, and another G2105A causes changes in the protein, p.G702D, which occurs at the C terminus of the protein in the ER lumen. And other members of the family developed compound heterozygous mutations at these two sites, but none found relevant symptoms. So it is speculated that double homozygous mutations may be involved in the occurrence of Wolfram syndrome. Four base deletions of c.1314_1317delCTTT in family A proband caused p.F438Lfs * 3, WFS1 belongs to protein loss of function, which is the cause of patient diabetes, optic nipple atrophy, and diabetes insipidus, but hearing and development are not abnormal, we guess that this part of the truncated protein may exercise part of the protein function, the specific reason is not clear. A homozygous missense mutation in the proband of family D and his younger brother, c.C1885T, who is now 5 years old and also has diabetes. A c.G1393C homozygous missense mutation in family G proband caused changes in protein p.A465P, a locus occurring in the transmembrane region in the cytoplasm, where the proband, the same genotype as his brother, developed a severe Wolfram syndrome phenotype. In conclusion, we found that in seven families, in patients with different gene-phenotypes (Fig. 2), one mutation caused protein truncation, five missense mutations caused amino acid changes, and different protein regions, protein N, C, transmembrane regions, and cellular localization were the best cases for phenotype-genotype.

The main causal gene of Wolfram syndrome is WFS1, at present, we have collected clinical phenotypes, but it is not clear whether these mutants are directly involved in the development of the disease and the relationship between these mutations and the phenotypes. This study will further explore in the future by focusing on the effects of different types of mutants on the function of WFS1 protein and will reveal the link of different mutation sites to the pathogenesis of Wolfram syndrome. In addition, according to the complex diversity of clinical phenotypes, phenotype sequence and severe procedures, and genetic phenotypes, this study will continue to follow the track of members' ancestry and expand the screening scope, explore the correlation of different mutation sites and clinical phenotypes, and timely intervention and provide genetic counseling for accurate clinical diagnosis.

Wolfram syndrome

WFS1

Wolfram syndrome1

CISD2

CDGSH iron-sulfur domain-containing protein 2

Endoplasmic Reticulum

Ethics approval and consent to participate

The study was reviewed and approved by the Hospital Ethics Committee (KY2022102801), and all study subjects or their guardians signed an informed consent.

Consent for publication

Consent for publications were included in consent form.

Availability of data and materials

All patient data has been anonymized, and any further information may be obtained from the corresponding author.

Competing interests

The authors declare that they have no competing interests

Funding

Fund program:Regional Collaborative Innovation Project of Xinjiang Autonomous Region (Science and Technology Assistance Plan) (2019E0285)

Author contributions

D.D. and G.Y. designed research; A.T., M.Y, M.A., L.S., M.G. and J.Z. analyzed data; and D.D. wrote the paper.

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Journal Publication

published 16 Nov, 2023

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You are reading this latest preprint version

Wolfram Syndrome: Case series and review of the literature

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Journal Publication

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Abstract

Figures

Introduction

Methods

Ethics statement

Exome Sequencing And Variant Analysis

Results

Clinical presentation

Genetic Analysis

Discussion

Conclusions

Abbreviations

Declarations

References

Status:

Journal Publication

Version 1