17a-Hydroxylase/17,20-lyase (17OHD) deficiency (OMIM 202110) is a rare form of congenital adrenal hyperplasia (CAH). It is an autosomal recessive disease caused by a gene defect in cytochrome P450 family 17 subfamily A member 1 (CYP17A1). CYP17A1 is located on chromosome 10q24.3 (Sparkes et al., 1991). The full length of the gene is about 6.6 KB and includes eight exons and seven introns (Picado-Leonard and Miller, 1987). This gene transcribes an identical mRNA encoding cytochrome P450c17 enzyme in both adrenal glands and gonads (Chung et al., 1987). Mutations in CYP17A1 lead to functional deficiency of the P450c17 enzyme, which prevents the synthesis of glucocorticoids and sex hormones and leads to halocorticoid accumulation. The main clinical manifestations are hypertension, hypokalemia, female sexual infantile and primary amenorrhea, and male sex development disorder. The true incidence of 17OHD is unknown but may be approximately 1 in 50,000 (El-Maouche et al., 2017). Most known mutations appear to be novel, with 148 new mutations characterized in the Human Gene Mutation Database.

Moyamoya disease (MMD) is a chronic and progressive occlusive cerebrovascular disease of unknown etiology. MMD mainly manifests as stenosis or occlusion of the distal ends of bilateral internal carotid arteries and their large branches, accompanied by an abnormal neovascularization network (moyamoya vessels) at the base of the skull (“moyamoya” is the Japanese term for a “puff of smoke”), as described by Suzuki and Takaku (1969). The prevalence of MMD in Japan is 10.5/100,000, while the incidence is 0.94/100,000 (Baba et al., 2008). The incidence rate in Nanjing from 2000 to 2007 was 3.92/100,000 (Miao et al., 2010). The clinical manifestations of MMD mainly fall into two categories: 1) hemorrhage and 2) ischemia. The onset ages of MMD are approximately 5 and 40 years (Miao et al., 2010). Epidemiological studies show that MMD mainly occurs in Asian countries. Nearly 10% of patients in Asian countries have a family history of MMD, indicating the important role of genetic factors in its pathogenesis (Bersano et al., 2016).

The coexistence of 17OHD and MMD in one person is extremely rare, with only one previous case reported worldwide (Gao et al., 2019). This study reports the case of a 28-year-old patient with clinical features of 17OHD and MMD is reported, and the characteristics of her genetic defect were analyzed.

After the variants were filtered, the correlation degree of the phenotype analysis was determined by “primary amenorrhea, hypokalemia, hypertension, and moyamoya disease” in which the values of the selected genes were significantly higher than those of other genes. Finally, four variants from CYP17A1, CNOT3, and PCNT were chosen. These variants were validated by Sanger sequencing and compared to the normal human sequence in GenBank (NM_000102.3, NM_014516.3, NM_006031.5). CNOT3 and PCNT variants have not been reported in the HGMD database. The clinical diagnosis of MMD was confirmed based on the radiological evaluations (Scott and Smith, 2009). The diagnosis of 17OHD was supported by the CYP17A1 mutation in conjunction with the findings of the biochemical and clinical evaluations.

The patient was diagnosed with 17OHD at 20 years of age based on the presence of amenorrhea, sexual infantilism, hypertension, and hypokalemia. She had a 46, XY karyotype and was homozygous for c.297+2T>C. This mutation was previously reported in China and Taiwan (Hwang et al., 2011; Dong et al., 2016; Li et al., 2020). However, none of these reported cases were associated with MMD. Hwang et al. (2011) detected the transcription of CYP17A1 in patients by in vitro expression testing of an allogeneic minigene vector and reported that the mutation of this intron (c.297+2T>C) constituted a functional splicing site, resulting in the incorrect splicing of most of the mRNA transcripts (>90%) of CYP17A1. Through abnormal mRNA splicing into the pseudo-exons, the reading frame can be shifted and terminated prematurely, and the activity of 17a-hydroxylase/17,20-lyase is destroyed. Only correctly spliced products express normal exons and retain a fraction of the 17a-hydroxylase/17,20-lyase activity thus explaining the origin of the low but detectable serum cortisol levels, in this severely affected patient.

Deficient 17a-hydroxylase/17,20-lyase activity leads to the lack of formation of progesterone and 17a-hydroxylate pregnenolone, which prevents cortisol synthesis and accounts for elevated ACTH levels and overproduction of 17-deoxycorticosteroids by the zona fasciculata. Elevated corticosterone and deoxycorticosterone (DOC) levels lead to increased mineralocorticoid activity and subsequent sodium retention, volume expansion, and hypertension with suppressed renin and aldosterone (Auchus, 2001). At the same time, DOC causes increased potassium excretion from renal collecting tubules and subsequent hypokalemia (Zennaro et al., 2015). The patient was treated with oral dexamethasone (0.375 mg once daily), which led to an improvement in blood pressure, returned the potassium levels to the normal range, and suppressed corticosterone production.

However, the patient discontinued treatment 1 year later due to significant weight gain. Her blood pressure ranged from 150/110 to 160/120 mmHg after withdrawal. At 25 years of age, a left anterior communicating aneurysm and a bilateral middle cerebral artery occlusion were identified following sudden syncope. The patient was consequently diagnosed with MMD. MMD is a chronic and progressive occlusion cerebrovascular disease with unknown etiology. In Japan, about 10% of patients have affected first-degree relatives (Fukui et al., 2000). Associations with loci on chromosomes 17, 8, 6, and 3 in addition to specific HLA haplotypes, have previously been described (Fukui et al., 2000; Han et al., 2003; Sakurai et al., 2004).

In this patient, whole-exome sequencing revealed CNOT3 and PCNT variants that might be related to MMD. Pinard et al. (2020) reported new mutations in CNOT3 that were not previously associated with MMD and also identified them in unrelated MMD probands. CNOT3 encodes proteins related to chromatin remodeling, together with YY1AP1, leading to MMD-like cerebrovascular occlusive disease, (Guo et al., 2017) suggesting that disrupted chromatin remodeling is a predisposing factor leading to early-onset non-atherosclerotic occlusive cerebrovascular disease. PCNT is located on chromosome 21, its diallelic dysfunction mutations can lead to microcephaly osteodysplasia primordial dwarfism type II disease (OMIM 210720), and about 50% of patients develop cerebrovascular abnormalities, including MMD, intracranial aneurysm (IAs), and subarachnoid hemorrhages (SAHs), as described by Bober et al. (2010). In addition, a previously described complete Pcnt knockout mouse model (Pcnt −/−) showed systemic vascular abnormalities, including intracranial hemorrhage (Chen et al., 2014), suggesting that PCNT is an important factor in MMD pathogenesis.

Although previous literature suggested that CNOT3 and PCNT mutations may be pathogenic causes of MMD, the variants in the present patient were heterozygous with unknown significance; thus, further studies are needed. Moreover, CNOT3, PCNT, and CYP17A1 are on different chromosomes, and CYP17A1, encoding the only cytochrome P450c17 enzyme, is only expressed in adrenal glands and gonads (Chung et al., 1987). Therefore, an association between 17OHD and MMD was not supported at the genetic level. However, Manolio et al. (2009) suggested that mutated heterozygous vectors in recessive genetic diseases may have led to an increased phenotypic risk of diseases or complex diseases. These findings require more research.

To characterize the relevance between MMD and 17OHD or Congenital Adrenal Hyperplasia (CAH), a literature review was performed. Three articles were identified from the PubMed, Web of Science, and CNKI China databases and are summarized in Table 3 (Wang et al., 2001; Gao et al., 2019; Vasudevan et al., 2019). As shown in Table 3, 17OHD with MMD is not an occasional case, and the locus of CYP17A1 mutation is not associated with MMD. Thus, patients with 17OHD with no obvious neurological discomfort or severe hypertension would not receive cerebrovascular imaging examination. Consequently, they would not have the chance to be diagnosed with MMD.

Several genetic syndromes, such as neurofibromatosis type I (OMIM 162200) have been described by Friedman et al. (2002), while Moyamoya angiopathy with achalasia and hypertension (OMIM 615750) was described by Herve et al. (2014). These genetic findings highlight potential molecular pathways, including the deletion of nitric oxide signaling (GUCY1A3), that could account for MMD (Herve et al., 2014) and activation of proliferative pathways (NF1) (Friedman et al., 2002). Therefore, 17OHD may also be a risk factor for MMD. One hypothesis proposed that hypertension and hypokalemia caused by increased deoxycorticosterone levels due to CYP17A1 defects may play a dominant role in the pathogenesis of MMD, which requires further exploration. Several previous cases also mentioned that patients with 17OHD had a history of cerebral hemorrhage or cerebral ischemia (Mita et al., 1983; Yu et al., 2010; Zhang et al., 2021). No clear correlation in genetic levels between 17OHD and MMD in patients with 17OHD and hypertension was found. However, the risk of cerebrovascular accidents should be considered.

The coexistence of 17OHD and MMD in one person is extremely rare. No other study on the genetic analysis of 17OHD accompanied by MMD has been published. Cerebral ischemia and hemorrhage are important risks affecting the quality of life and prognosis of patients with 17OHD. Therefore, cerebrovascular examination in these patients may help to prevent life-threatening intracranial vascular disease. Early diagnosis allows the safe administration of treatments such as revascularization and can prevent or reduce long-term sequelae in these patients.