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

Neurophysiological Characteristics of Allgrove (Triple A) Syndrome: Case Report and Literature Review

Allgrove or “Triple A” syndrome is characterized by alacrima, achalasia, and adrenocorticotropic hormone-resistant adrenal insufficiency, as well as central and peripheral nervous system involvement. Patients demonstrate heterogeneity with regard to their age of symptom onset, disease severity, and nature of clinical symptoms. Neurophysiological testing has also shown variability ranging from: motor neuron disease with prominent bulbar involvement, motor-predominant neuropathy, or sensorimotor polyneuropathy with axonal or mixed axonal and demyelinating features. We report an 11-year-old boy who presented with neurological symptoms of progressive spasticity and peripheral neuropathy. His neurophysiological testing confirmed a sensorimotor polyneuropathy with axonal and demyelinating features. Exome sequencing identified compound heterozygote variants in the AAAS gene. We summarize the neurophysiological findings in him and 29 other patients with Allgrove syndrome where nerve conduction study findings were available thereby providing a review of the heterogeneity in neurophysiological findings that have been reported in this rare disorder.

Homozygous deletion of the entire AAAS gene in a triple A syndrome patient

Triple A syndrome, a multisystemic autosomal recessive disease, is characterized by the clinical triad of adrenal insufficiency, alacrima and achalasia in combination with progressive neurological impairments. The disorder is caused by homozygous or compound heterozygous mutations in the AAAS gene. Here we present the clinical and molecular data of a ten year old patient with triple A syndrome. Array CGH analysis confirmed the PCR-based assumption of a homozygous deletion of the entire AAAS gene in the patient and a heterozygous deletion in both parents. We demonstrate that the patient carries a 15 kb deletion and identified the 5' and 3' breakpoints outside the AAAS gene. This is the first report of a triple A syndrome patient with a homozygous deletion of the entire 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.

Triple A syndrome with a novel indel mutation in the AAAS gene and delayed puberty

Triple A syndrome, formerly known as Allgrove syndrome, is an autosomal recessive disorder characterized clinically by adrenal insufficiency, alacrima, achalasia, and neurological abnormalities. We report a 17-year-old boy presented to the endocrine clinic with delayed puberty and a 4-year's history of fatigue and muscle weakness. He had achalasia, alacrima, and skin and mucosal hyperpigmentation. Hormonal assessment revealed isolated glucocorticoid deficiency. Clinical diagnosis of triple A syndrome was confirmed by sequencing the entire coding region including exon-intron boundaries of the AAAS gene. Analysis revealed a homozygous novel indel mutation encompassing intron 7 to intron 10 of the gene (g.16166_17813delinsTGAGGCCTGCTG; NG_016775). This is the first report of triple A syndrome in Jordan with a novel indel mutation and presenting with delayed puberty.

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.

Localized DNA cleavage secondary to genotoxic exposure adjacent to an Alu inverted repeat

Radiation is a potent inducer of DNA damage leading to both random DNA loss and mutation. As part of a study focused on the mechanism whereby cells undergo loss of heterozygosity (LOH), a region of common LOH telomeric termination at 11q24 was observed in clones of H292 mucoepidermoid cells established after irradiation (IR). A 10-kbp region including the telomeric extent of LOH termination was analyzed after IR using six sets of ligation-mediated polymerase chain reaction (PCR) primers to detect the presence of DNA breaks. A cluster of DNA breaks was detected that closely mapped to the telomeric extent of LOH and which were observed up to 8 hr after IR. Repeating the experiment in the presence of the inhibitor of apoptosis, zVAD.fmk, did not change the location or amount of cleavage. A similar distribution of breaks was also seen in the MCF-10A breast cancer cell line after IR. Further inspection of the involved region showed that 22/32 and 7/7 DNA breaks found in H292 and MCF-10A cells, respectively, were located either in or immediately adjacent to an AluSx1 sequence, itself ≈ 1 kbp 5' to an AluSq2 that was in an inverted orientation to the AluSx1. The region between the inverted Alu repeats was notable for both DNAse hypersensitivity and an open chromatin conformation inferred from histone modification data. These factors may contribute to genomic instability at this location.

Copy number variation

Recent genetic epidemiology studies have been dominated by genome-wide association (GWA) studies using single nucleotide polymorphisms (SNPs). However, a form of structural genomic variation, termed copy number variation (CNV), is also widespread throughout the human genome, and can be highly polymorphic between individuals. Such variation has long been shown, through candidate gene studies using low-throughput molecular biology techniques, to have direct consequences on human health and variation. Many studies have now sought to extensively characterise this variation on a genome-wide scale and, increasingly, attempts are being made to identify associations between CNV and human disease. Although many of the study design issues that have been described for SNP GWA studies are also relevant for CNV GWA studies, CNV studies also present their own unique set of challenges and considerations. New microarray-based technologies are enabling more accurate mapping of CNVs, and CNV maps of the human genome are being regularly refined with increasing resolution. The study of CNV and its effects on human health and disease therefore present a dynamic and exciting challenge for researchers in the field of genetic epidemiology.

Two siblings with triple A syndrome and novel mutation presenting as hereditary polyneuropathy

The clinical and molecular data on triple A syndrome in two siblings (girl 3.5 years and boy 5.5 years at presentation) with early onset of neurological dysfunction are described. Both patients showed delayed developmental milestones and neurological dysfunctions (motor and sensory demyelinating neuropathy, marked hyperreflexia, calves hypothrophy, pes cavus, gait disturbance) in early childhood, when erroneously diagnosed with hereditary polyneuropathy, most likely Charcot-Marie-Tooth disease. After a severe adrenal crisis in the younger sister at the age of 3 years, the older brother aged 5.5 years was also evaluated and latent adrenal insufficiency was discovered. As both of the siblings had alacrima, hyperkeratosis of palms, cutis anserina, and nasal speech, diagnosis of triple A syndrome was considered. Sequencing of the AAAS gene detected a compound heterozygous mutation consisting of a novel mutation p.Ser296Tyr (c.887C>A) in exon 9 and a previously described p.Ser263Pro (c.787T>C) missense mutation in exon 8 in both siblings. In conclusion, triple A syndrome should be considered in patients presenting with early neurological dysfunction and developmental delay. Alacrima as the earliest and most consistent clinical sign should be investigated by Schirmer test. Patients should be regularly tested for adrenal dysfunction to prevent life-threatening adrenal crises.

The molecular basis of adrenocorticotrophin resistance syndrome

Adrenocorticotrophin resistance syndromes comprise familial glucocorticoid deficiency (FGD) and triple A syndrome, which are rare autosomal recessive diseases with distinct clinical features and molecular etiologies. Mutations of melanocortin-2 receptor (MC2R) have been described in segregation with FGD in 25% of patients. More recently melanocortin-2 receptor accessory protein (MRAP), a small single-transmembrane domain protein, was described as an essential protein for the traffic of MC2R and its expression on the plasma membrane. About 20% of FGD patients carry homozygous mutations of MRAP. The ALADIN protein (for alacrima/achalasia/adrenal insufficiency/neurologic disorder) was identified as the molecular basis of triple A syndrome. The elucidation of the genetic basis of the ACTH resistance syndrome has contributed to the better understanding of MC2R function. However, in some patients the molecular etiology is not yet known and awaits further genetic studies.