The purpose of the study was to evaluate endocrine patterns of patients with congenital adrenal hyperplasia and each gene mutation and to analyze the correlation between each phenotype and genotype.
This was a retrospective study of the patients with congenital adrenal hyperplasia in the pediatric outpatient clinic at the Samsung Medical Center from November 1994 to December 2012. We analyzed the medical records of 27 patients (male, 19; female, 8) with congenital adrenal hyperplasia who had been diagnosed by genetic testing to have 21-hydroxylase deficiency.
In genetic analysis of 54 alleles from 27 patients, 13 types of mutations were identified. The distribution of 21-hydroxylase deficiency gene mutations revealed that intron 2 splice site (c.293-13A/C>G) mutations and large deletions were the most common, at 31.5% and 22.2% respectively, followed by p.I173N, p.R356W, and p.I172N mutations at 11.1%, 9.3%, and 9.3%, respectively. Other mutations were observed at 1.9-3.7%. No novel mutations were detected.
The analysis of 54 alleles revealed 13 types of mutation. The salt wasting form showed a good correlation between genotype and phenotype, but the simple virilizing and nonclassic forms showed inconsistencies between genotype and phenotype. The distribution of
Congenital adrenal hyperplasia (CAH) is an autosomal recessive genetic disease that affects the process of cortisol synthesis in the adrenal gland. The cause of CAH in 90-95% of affected individuals is a deficiency of 21-hydroxylase
Based on the severity of the clinical manifestations, the 21-hydroxylase deficiency is classified into classic form, known as salt-wasting (SW) and simple virilizing (SV) type, and a nonclassic (NC) form called late-onset type. The classic form generally occurs at incidence of 1:10,000-1:15,000, while the NC form occurs in 1:1000 persons
Clinical symptoms may appear at diagnosis. Symptoms that appear during the neonatal period in the SW form are repetitive vomiting, diarrhea, tachypnea or shortness of breath, and weight loss. Cases with severe lack of cortisol and aldosterone can show hyponatremia, hyperkalemia, dehydration, and shock in the early postnatal period
The 21-hydroxylase genes,
The purpose of this study was to evaluate endocrine patterns of patients with CAH according to their genetic mutations. We also analyzed the correlation between each phenotype and genotype.
Clinical data were collected retrospectively from a review of medical records of patients who visited the pediatric outpatient clinic at Samsung Medical Center, from November 1994 to December 2012. Twenty-seven patients (male, 19; female, 8) with CAH who had been diagnosed by genetic testing to have 21-hydroxylase deficiency. The Institutional Review Board of Samsung Medical Center approved this study (2013-04-065).
Data for physical examination, height, weight, electrolyte level, and hormonal level were collected from medical records. Pubertal status was assessed with the Tanner stage of breast development for girls and genital development for boys. BA was measured using the method described by Greulich and Pyle
The Wizard Genomic DNA Purification Kit (Promega, Madison, WI, USA) was used to extract genomic DNA from peripheral blood samples of all patients. All exons of the
The patients were divided into two groups: SW form and SV form. Each phenotype was further divided by gender. The age at diagnosis, ratio of BA to CA, BMI and hydrocortisone dose of different phenotypic groups were evaluated. The Wilcoxon signed rank test was used for between-group comparison. Statistical analyses were performed using IBM SPSS ver. 20.0 (IBM Co., Armonk, NY, USA).
Among the 27 patients for whom follow-up observations were possible, the classic form of 21-hydroxylase deficiency was found in 26 patients. These included 15 patients (57.7%) with the SW form (male, 11; female, 4), 11 (40.7%) with the SV form (male, 7; female, 4), and 1 male patient (3.7%) with the NC form. The mean follow-up observation periods were 9.00±5.17 years for patients with the SW form, 8.38±3.68 years for patients with the SV form, and 16.4 years for the patient with the NC form. The mean age at diagnosis was 0.11±0.14 years (male, 0.13±0.16; female, 0.05±0.04) for SW form patients and 7.19±5.62 years (male, 7.57±4.07; female, 6.52±8.48) for SV form patients. The SW form was diagnosed at a significantly earlier age in comparison with the SV form (
The mean value of the BA to CA ratio at diagnosis was 1.39±0.40 (male, 1.23±0.31; female, 1.74±0.37) for the SW form patients and 1.57±0.72 (male, 1.52±0.46; female, 1.65±1.23) for the SV form patients; these differences were not statistically significant. The final BA to CA ratio was 1.25±0.14 (male, 1.26±0.16; female, 1.24±0.11) in the SW form patients and 1.23±0.19 (male, 1.31±0.17; female, 1.10±0.16) in the SV form patients; again, the differences were not statistically significant. The boy with the NC form had a BA to CA ratio of 1.0 at diagnosis and a final value of 1.03.
The mean BMI values at the last follow-up were 20.1±4.49 kg/m2 (male, 21.0±4.85 kg/m2; female, 17.7±2.20 kg/m2) for patients with the SW form, and 21.2±3.26 kg/m2 (male, 22.6±3.87 kg/m2; female, 19.8±1.09 kg/m2) for patients with the SV form. There were no significant differences between males and females and between the SW form and SV form groups (
Endocrine tests performed on the 27 patients for whom follow-up observations were possible revealed that the levels of 17-OHP, ACTH, renin, and testosterone were normalized by hydrocortisone treatment (
The analysis of 54 alleles of genes in the 27 patients for whom follow-up observations were possible revealed 13 types of mutations. The distribution of 21-hydroxylase deficiency gene mutations revealed that intron 2 splice site (c.293-13A/C>G) mutations and large deletions were the most common, at 31.5% and 22.2% respectively, followed by p.I173N, p.R356W, and p.I172N mutations at 11.1%, 9.3%, and 9.3%, respectively. Other mutations were observed at 1.9-3.7%. No novel mutations were detected (
The most common mutations in the patients with SW form were the c.293-13A/C>G and large deletion at 36.7% and 33.3% respectively, followed by p.R356W, p.I172N, and p.I173N mutations. Among these patients, a total of 6 patients were homozygotes, accounting for 40.0%: 2 patients had the c.293-13A/C>G mutation, 2 patients had large deletion, 1 patient had a p.I173N mutation, and 1 patient had a p.R356W mutation. The rest of the mutations were found in compound heterozygotes, but no complex alleles were detected (
The most common mutations in the patients with SV form were c.293-13A/C>G, p.I173N, and p.I172N, at 27.3%, 18.2%, and 13.6% respectively, followed by large deletion, p.R356W, p.S171N, p.8bp-del, p.R484Pfs, p.L307FfsX6, and p.L306FfsX5. No homozygotes were found among these patients, but complex alleles were observed in 2 patients with large deletion + c.293-13A/C>G/c.293-13A/C>G+p.L306FfsX5 and p.I173N+p. Q318X+p.R357W (
CAH is a series of autosomal recessive diseases that produce a cortisol synthesis disorder due to enzyme deficiency imparted by gene mutations that include cytochrome P450c21. The result is adrenal hyperplasia and an excessive accumulation of cortisol precursors and androgen. Several clinical findings, such as virilization of external genitalia and loss of salt, occur in response to intermediary metabolites
The 21-hydroxylase gene is composed of
The correlation between 21-hydroxylase genotype and phenotype has been studied in a variety of ethnic groups
Early diagnosis of this disease can occur for the SW form, which shows acute symptoms at a relatively early age, and for girls with SV, who show external genital abnormality at birth. However, no striking symptoms are observed in boys with the SV form, so diagnosis is often delayed, as seen in previous reports
Patients with the SW or SV form usually show a shorter final adult height than the average adult height, of approximately 1-2 SD (standard deviation)
Wilkins et al.
Recently, Choi et al.
The frequencies of gene mutations causing 21-hydroxylase deficiency in this study showed discrepancy from the numerical values in other domestic and overseas reports, but the common mutation types were consistent, with c.293-13A/C>G, large deletion, p.R356W, p.I172N, and p.I173N accounting for most of the mutations. The
In conclusion, the mutations of the
The distribution of
No potential conflict of interest relevant to this article was reported.
Clinical and laboratory finding of the patients with 21-hydroxylase deficiency
Variable | Salt wasting |
Simple virilizing |
Nonclassic |
|||
---|---|---|---|---|---|---|
Male | Female | Male | Female | Male | Female | |
No. of patient | 11 | 4 | 7 | 4 | 1 | 0 |
Age at diagnosis (yr) | 0.13±0.16 | 0.05±0.04 | 7.57±4.07 | 6.52±8.48 | 6 | |
BA/CA | ||||||
Initial | 1.23±0.31 | 1.74±0.37 | 1.52±0.46 | 1.65±1.23 | 1.00 | |
Final | 1.26±0.16 | 1.24±0.11 | 1.31±0.17 | 1.10±0.16 | 1.03 | |
Body mass index (kg/m2) | ||||||
Initial | 13.50±2.17 | 12.20±2.89 | 17.42±3.70 | 17.80±3.65 | 16.64 | |
Final | 21.01±4.85 | 17.72±2.20 | 22.63±3.87 | 19.81±1.09 | 28.00 | |
17-OHP (ng/mL) | ||||||
Initial | 331 (30–1892) | 114 (79–128) | 151 (125–191) | 342 (99–583) | 38.43 | |
Final | 13.64 (0.13–72) | 1.52 (0.72–2.34) | 3.02 (0.13–7.72) | 4.84 (1.91–9.73) | 64.00 | |
ACTH (pg/mL) | ||||||
Initial | 168 (16–344) | 601 (17–1780) | 257 (119–473) | 495.00 (7.13–1,493.00) | 54.00 | |
Final | 45 (7.24–158) | 18 (18) | 35 (18–48) | 47 (25–71) | 4.83 | |
Testosterone (ng/mL) | ||||||
Initial | 0.83 (0.04–3.32) | 11 (0.74–20) | 3.33 (1.24–5.23) | 1.03 (0.94–1.01) | 1.67 | |
Final | 0.62 (0.01–2.91) | 0.13 (0.13) | 2.54 (0.01–3.20) | 0.07 (0.01–0.12) | 4.28 | |
Renin (ng/mL), initial | 32.00 (8.40–72.00) | 34 (34) | 19 (16–21) | 8.34 (8.20–8.53) | 6.75 |
Values are presented as mean±standard deviation or median (range).
BA, bone age; CA, chronological age; 17-OHP, 17-hydroxyprogesterone; ACTH, adrenocorticotropic hormone.
Phenotype and genotype of 27 patients with 21-hydroxylase deficiency
Patient | Sex | Phenotype | Genotype |
---|---|---|---|
1 | Male | SW | c.293-13A/C>G/c.293-13A/C>G |
2 | Female | SW | c.293-13A/C>G/c.293-13A/C>G |
3 | Male | SW | c.293-13A/C>G/8-bp del |
4 | Male | SW | c.293-13A/C>G/large deletion |
5 | Male | SW | c.293-13A/C>G/large deletion |
6 | Male | SW | c.293-13A/C>G/p.R356W |
7 | Male | SW | Large deletion/large deletion |
8 | Male | SW | Large deletion/large deletion |
9 | Male | SW | Large deletion/c.293-13A/C>G |
10 | Male | SW | Large deletion/c.293-13A/C>G |
11 | Female | SW | Large deletion/conversion |
12 | Male | SW | p.I172N/large deletion |
13 | Female | SW | p.I173N/p.I173N |
14 | Male | SW | p.R356W/p.R356W |
15 | Male | SW | c.293-13A/C>G/p.R356W |
16 | Male | SV | Large deletion+c.293-13A/C>G/c.293-13A/C>G+p.L306FfsX5 |
17 | Male | SV | Large deletion/p.R356W |
18 | Male | SV | c.293-13A/C>G/p.I173N |
19 | Male | SV | c.293-13A/C>G/p.R484Pfs |
20 | Male | SV | c.293-13A/C>G/p.S171N |
21 | Female | SV | c.293-13A/C>G/p.8-bp del |
22 | Male | SV | p.I172N/p.L307FfsX6 |
23 | Female | SV | p.I172N/p.L306FfsX5 |
24 | Female | SV | p.I172N/c.293-13A/C>G |
25 | Female | SV | p.I173N/p.I173N |
26 | Male | SV | p.I173N+p.Q318X+p.R357W |
27 | Male | NC | Large deletion/p.I172N |
SW, salt wasting; SV, simple virilizing; NC, nonclassic; 8-bp del, 8-bp deletion.
Allelic frequency of
Mutation | Salt wasting | Simple virilizing | Nonclassic | Total |
---|---|---|---|---|
c.293-13A/C>G | 11 (36.7) | 6 (27.3) | 0 (0) | 17 (31.5) |
Large deletion | 10 (33.3) | 1 (4.5) | 1 (50.0) | 12 (22.2) |
p.R356W (c.1066C>T) | 4 (13.3) | 1 (4.5) | 0 (0) | 5 (9.3) |
p.S171N (c.512T>A) | 0 (0) | 1 (4.5) | 0 (0) | 1 (1.9) |
p.I172N (c.515T>A) | 1 (3.3) | 3 (13.6) | 1 (50.0) | 5 (9.3) |
p.I173N (c.518T>A) | 2 (6.6) | 4 (18.2) | 0 (0) | 6 (11.1) |
Conversion | 1 (3.3) | 0 (0) | 0 (0) | 1 (1.9) |
8-bp deletion (c.329_336delGAGACTAC) | 1 (3.3) | 1 (4.5) | 0 (0) | 2 (3.7) |
p.R484Pfs (c.1451dupC) | 0 (0) | 1 (4.5) | 0 (0) | 1 (1.9) |
p.L307FfsX6 (c.920_921insT) | 0 (0) | 1 (4.5) | 0 (0) | 1 (1.9) |
p.L306FfsX5 (c.920dupT) | 0 (0) | 1 (4.5) | 0 (0) | 1 (1.9) |
Large deletion+c.293-13A/C>G+p.L306FfsX5 (c.920dupT) | 0 (0) | 1 (4.5) | 0 (0) | 1 (1.9) |
p.Q318X+p.R357W (c.955C>T+c.1069C>T) | 0 (0) | 1 (4.5) | 0 (0) | 1 (1.9) |
Total | 30 (100) | 22 (100) | 2 (100) | 54 (100) |
Values are presented as number (%).