Triple-A syndrome--the first Chinese patient with novel mutations in the AAAS gene

Clinical decision making and application of an active rehabilitation program for a person with the neuromuscular symptoms of Allgrove syndrome: a case report

BACKGROUND

Allgrove syndrome is a multisystem disorder first described in 1978 and is classically associated with esophageal achalasia, alacrima, and adrenal insufficiency. Allgrove syndrome is caused by homozygous and/or compound heterozygous mutations on Chromosome 12q13, designated as "AAA" (Achalasia, Addisonianism Alacrima). AAA encodes the protein ALADIN (Alacrima, Achalasia, aDrenal Insufficiency Neurologic disorder), a member of the nuclear porin family forming the nuclear pore complex.

PURPOSE

The purpose of this case report is to illustrate the clinical decision making and results following an active rehabilitation program on a patient with Allgrove syndrome. A detailed physical examination is also provided to contribute to the body of knowledge regarding the clinical presentation of this disorder.

CONCLUSION

It appears that in this case, this patient with Allgrove syndrome demonstrated a significant increase in endurance, balance, and a return to functional activities and participation following a 10-week physical therapy program consisting of task-oriented exercise, aerobic training, postural control exercises, and patient education. Due to the pathophysiology of Allgrove syndrome, these patients cannot be exercised in a traditional manner. It is prudent to perform these interventions with precautions including frequent monitoring of vitals, rest breaks in cool environments, close supervision during balance tasks, and submaximal exercise at a Borg scale of moderate intensity. C.A.'s overall improvements illustrate the potential value of complementing the medical management of persons with Allgrove syndrome with active exercise interventions.

Phenotype-genotype spectrum of AAA syndrome from Western India and systematic review of literature

OBJECTIVE

To study genotype-phenotype spectrum of triple A syndrome (TAS).

METHODS

Retrospective chart analysis of Indian TAS patients (cohort 1, n = 8) and review of genotyped TAS cases reported in world literature (cohort 2, n = 133, 68 publications).

RESULTS

Median age at presentation was 4.75 years (range: 4-10) and 5 years (range: 1-42) for cohorts 1 and 2, respectively. Alacrima, adrenal insufficiency (AI), achalasia and neurological dysfunction (ND) were seen in 8/8, 8/8, 7/8 and 4/8 patients in cohort 1, and in 99, 91, 93 and 79% patients in cohort 2, respectively. In both cohorts, alacrima was present since birth while AI and achalasia manifested before ND. Mineralocorticoid deficiency (MC) was uncommon (absent in cohort 1, 12.5% in cohort 2). In cohort 1, splice-site mutation in exon 1 (p.G14Vfs*45) was commonest, followed by a deletion in exon 8 (p.S255Vfs*36). Out of 65 mutations in cohort 2, 14 were recurrent and five exhibited regional clustering. AI was more prevalent, more often a presenting feature, and was diagnosed at younger age in T group (those with truncating mutations) as compared to NT (non-truncating mutations) group. ND was more prevalent, more common a presenting feature, with later age at onset in NT as compared to T group.

CONCLUSION

Clinical profile of our patients is similar to that of patients worldwide. Alacrima is the earliest and most consistent finding. MC deficiency is uncommon. Some recurrent mutations show regional clustering. p.G14Vfs*45 and p.S255Vfs*36 account for majority of AAAS mutations in our cohort. Phenotype of T group differs from that of NT group and merits future research.

Identification of AAAS gene mutation in Allgrove syndrome: A report of three cases

Allgrove syndrome (AS) is an autosomal recessive congenital disease, caused by mutations in the AAAS gene, and is characterized by the triad of Addison's disease, achalasia and alacrima. The present study describes three newly diagnosed cases of AS, in which genetic analysis of the AAAS gene was used to identify AAAS gene mutations, to enhance the understanding of the pathogenesis and clinical manifestations of AS in the Chinese population. Two of the cases exhibited homozygous mutations of c.771delG (p.Arg258GlyfsX33) in exon 8 and one case exhibited a homozygous mutation of c.1366C>T (p.Q456X) in exon 15. A review of the current literature suggests that the AAAS c.771delG mutation has only been reported in the Chinese population. Genetic analysis of the AAAS gene in Chinese AS patients at a young age may facilitate an earlier diagnosis and the timely initiation of the appropriate treatment, ultimately improving the patient outcome.

Long-term clinical follow-up and molecular genetic findings in eight patients with triple A syndrome

The triple A syndrome (Allgrove syndrome, OMIM #231550) is caused by autosomal recessively inherited mutations in the AAAS gene on chromosome 12q13 encoding the nuclear pore protein ALADIN. This multisystemic disease is characterised by achalasia, alacrima, adrenal insufficiency and neurological impairment. We analyse long-term clinical follow-up and results of sequencing of the AAAS gene in eight patients with triple A syndrome aged from 2 to 35 years. At the time of diagnosis, all patients presented with alacrima, neurological dysfunction, dermatological abnormalities, seven of them with adrenal insufficiency and five of them with achalasia. Sequencing of the AAAS gene identified the p.S263P mutation in five of eight patients, supporting the hypothesis that this mutation is a founder mutation in Slavic population. One of the patients is homozygous for the p.S263P mutation, two are compound heterozygous for the p.S263P and the p.G14fs mutation, two are compound heterozygous for the p.S263Pro mutation and p.S296Y mutation, two are compound heterozygous for the p.G14fs and the p.Q387X mutations and one is homozygous for the p.Q387X mutation. In the course of the follow-up time of 4-29 years, progression of existing and appearance of new symptoms developed. Although severe, many of these symptoms presented in all six young adult patients are often overlooked or neglected: postural hypotension with blurred vision and syncope, hyposalivation resulting with complete edentulosis, talocrular contractures with permanent walking difficulties and erectile dysfunction in male patients. Triple A syndrome is a progressive debilitating disorder which may seriously affect quality of life and even be life-threatening in patients with severe neurological impairment.

CONCLUSION

Long-term follow-up of patients with triple A syndrome revealed a variety of the clinical features involving many systems. Progressive natural course of the disease may seriously affect quality of life and even be life-threatening in patients with severe neurological impairment.

An Alu-mediated rearrangement causing a 3.2kb deletion and a novel two base pair deletion in AAAS gene as the cause of triple A syndrome

Triple A syndrome is an autosomal recessive disorder resulting from deleterious mutations in the AAAS gene located on chromosome 12q13. Typical clinical presentation of this syndrome includes adrenal insufficiency, achalasia, and alacrima. A 10-year-old female was diagnosed with Triple A syndrome at the age of 1 year. Initial analysis of the AAAS gene revealed apparently homozygosity for a novel 2bp deletion in exon 1. The father of the patient was heterozygous for this mutation but the mother and the maternal grandparents were apparently homozygous for the wild-type. Further studies demonstrated that the patient carried an intragenic 3.2kb deletion within both 5' and 3' breakpoints located within Alu-repeats. The deletion includes 5'-flanking region, exon 1, intron 1, exon 2, and part of intron 2 sequences of the AAAS gene. This Alu-mediated deletion was inherited from her mother and maternal grandmother. This is the first report that Alu-mediated rearrangement in conjunction with a novel two-bp deletion of the AAAS gene is a cause of Triple A syndrome. The results of our study lead to the hypothesis that an Alu-mediated mechanism may be responsible for large alterations in the AAAS gene. We also stress the importance of studying the family in genetic recessive diseases, such as Triple A syndrome, to avoid incorrect diagnosis and to provide accurate genetic counseling.

The genetics of ACTH resistance syndromes

Inherited adrenocorticotropin (ACTH) resistance diseases are rare and include triple A syndrome and familial glucocorticoid deficiency (FGD). These conditions show genetic heterogeneity, i.e., the identical clinical phenotype may result from defects in more than one gene. Clinically, FGD is characterized only by ACTH resistance, while the triple A syndrome exhibits a variety of additional clinical features. FGD is caused by mutations in the ACTH receptor (melanocortin 2 receptor, MC2R) and the recently identified melanocortin 2 receptor accessory protein (MRAP) genes. In addition, linkage to a locus on chromosome 8 has been demonstrated. The identification of further genes in ACTH resistance syndromes may reveal novel aspects of MC2R signalling and trafficking. This review will summarize the clinical, biochemical and genetic aspects of these rare but informative diseases.