22q11.2 deletion presenting with severe hypocalcaemia, seizure and basal ganglia calcification in an adult man

Hypoparathyroidism and late-onset hypogonadism in an adult male with familial 22q11.2 deletion syndrome: a case report with 3-year follow-up and review of the literature

BACKGROUND

22q11.2 deletion syndrome (DiGeorge syndrome) is associated with multiple organ dysfunctions such as cardiac defects, immunodeficiency, and hypoplasia of parathyroid glands. Moreover, the phenotype of 22q11.2 DS has clinical variability and heterogeneity.

CASE PRESENTATION

In this report, we present the case of a 35-year-old patient with a past medical history that included recurrent infections, mild learning difficulties in childhood, pediatric obesity, and cataract. He was admitted to the endocrinology department for the management of hypogonadism and hypocalcemia. During the 3-year follow-up, the patient gradually developed primary hypoparathyroidism, hypogonadism, chronic renal failure, and heart failure, and his medical condition deteriorated. Meanwhile, in order to improve clinicians' awareness of the endocrine manifestations of adult 22q11.2 DS and reduce missed diagnoses, we reviewed 28 case reports of adult 22q11.2 DS to analyze the clinical characteristics.

DISCUSSION

Here, we report the case of a young man diagnosed with 22q11.2 DS presented a rare combination of multiple endocrine disorders. This is the first time that a patient with 22q11.2DS had late-onset hypogonadism caused by primary testicular failure combined with decreased pituitary gonadotropin reserve in a patient with 22q11.2DS.

Endocrine disorders and the cerebellum: from neurodevelopmental injury to late-onset ataxia

Hormonal disorders are a source of cerebellar ataxia in both children and adults. Normal development of the cerebellum is critically dependent on thyroid hormone, which crosses both the blood-brain barrier and the blood-cerebrospinal fluid barrier thanks to specific transporters, including monocarboxylate transporter 8 and the organic anion-transporting polypeptide 1C1. In particular, growth and dendritic arborization of Purkinje neurons, synaptogenesis, and myelination are dependent on thyroid hormone. Disturbances of thyroid hormone may also impact on cerebellar ataxias of other origin, decompensating or aggravating the pre-existing ataxia manifesting with motor ataxia, oculomotor ataxia, and/or Schmahmann syndrome. Parathyroid disorders are associated with a genuine cerebellar syndrome, but symptoms may be subtle. The main conditions combining diabetes and cerebellar ataxia are Friedreich ataxia, ataxia associated with anti-GAD antibodies, autoimmune polyglandular syndromes, aceruloplasminemia, and cerebellar ataxia associated with hypogonadism (especially Holmes ataxia/Boucher-Neuhäuser syndrome). The general workup of cerebellar disorders should include the evaluation of hormonal status, including thyroid-stimulating hormone and free thyroxine levels, and hormonal replacement should be considered depending on the laboratory results. Cerebellar deficits may be reversible in some cases.

An Adult Case of Chromosome 22q11.2 Deletion Syndrome Associated with a High-positioned Right Aortic Arch

Chromosome 22q11.2 deletion syndrome (22q11.2 DS) has a very wide phenotypic spectrum that includes dysmorphic features, cardiac anomalies, and hypocalcemia arising from hypoparathyroidism. We herein describe an adult case of 22q11.2 DS with associated hypoparathyroidism and anomalies of the aortic arch. Because the patient had been diagnosed with primary hypoparathyroidism at another hospital, a diagnosis of 22q11.2 DS had been overlooked. A chest X-ray examination revealed widening of the mediastinum caused by a high-positioned right aortic arch, and we subsequently confirmed a diagnosis of 22q11.2 DS using fluorescence in situ hybridization. Because primary hypoparathyroidism is a rare disorder, physicians should be aware of the variable phenotypic features of 22q11.2 DS.

Recurrent convulsions, hypocalcemia, and hypoparathyroidism related to delayed diagnosis of 22q11.2 deletion syndrome in a middle-aged man

Case

A 49-year-old man had idiopathic epilepsy with recurrent convulsions and history of cleft palate, mental retardation, schizophrenia, and cataract. He had convulsions the day before and on the day of admission. Fosphenytoin was given i.v.; his convulsion stopped, but he lost consciousness 2 h later and was admitted. Glasgow Coma Scale score on arrival was 3. Cerebral computed tomography showed bilateral calcification in the basal ganglia. Laboratory tests showed decreased serum calcium and albumin and increased creatine kinase. He regained consciousness after i.v. calcium gluconate administration. Additionally, he showed decreased parathyroid hormone and 1,25(OH)₂ vitamin D. Suspecting hypoparathyroidism, i.v. calcium gluconate was changed to oral vitamin D. His medical history and physical appearance suggested 22q11.2 deletion syndrome, confirmed by chromosomal analysis.

Outcome

The patient was discharged after 29 days and remains convulsion-free.

Conclusion

Hypocalcemia due to hypoparathyroidism should be considered in the differential diagnosis of adult recurrent convulsions.

Idiopathic Hypoparathyroidism (IHP) Presenting as "Schizophrenia:" A Case Report

Idiopathic hypoparathyroidism (IHP) with the onset of psychosis is a rare case in the psychiatric clinic. In this case report, we summarize the three facets of IHP, which contains the clinical, biochemical, and radiological features. Besides, the differential diagnosis of this case is supposed to be a highlight that IHP could have the main complaints of psychotic symptoms and featured signs on neuroimaging manifestation.

Intergenerational and intrafamilial phenotypic variability in 22q11.2 deletion syndrome subjects

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a common microdeletion syndrome, which occurs in approximately 1:4000 births. Familial autosomal dominant recurrence of the syndrome is detected in about 8-28% of the cases. Aim of this study is to evaluate the intergenerational and intrafamilial phenotypic variability in a cohort of familial cases carrying a 22q11.2 deletion.

METHODS

Thirty-two 22q11.2DS subjects among 26 families were enrolled.

RESULTS

Second generation subjects showed a significantly higher number of features than their transmitting parents (212 vs 129, P = 0.0015). Congenital heart defect, calcium-phosphorus metabolism abnormalities, developmental and speech delay were more represented in the second generation (P < 0.05). Ocular disorders were more frequent in the parent group. No significant difference was observed for the other clinical variables. Intrafamilial phenotypic heterogeneity was identified in the pedigrees. In 23/32 families, a higher number of features were found in individuals from the second generation and a more severe phenotype was observed in almost all of them, indicating the worsening of the phenotype over generations. Both genetic and epigenetic mechanisms may be involved in the phenotypic variability.

CONCLUSIONS

Second generation subjects showed a more complex phenotype in comparison to those from the first generation. Both ascertainment bias related to patient selection or to the low rate of reproductive fitness of adults with a more severe phenotype, and several not well defined molecular mechanism, could explain intergenerational and intrafamilial phenotypic variability in this syndrome.

Neuroanatomical phenotypes in a mouse model of the 22q11.2 microdeletion

Recurrent deletions at the 22q11.2 locus have been established as a strong genetic risk factor for the development of schizophrenia and cognitive dysfunction. Individuals with 22q11.2 deletions have a range of well-defined volumetric abnormalities in a number of critical brain structures. A mouse model of the 22q11.2 deletion (Df(16)A(+/-)) has previously been utilized to characterize disease-associated abnormalities on synaptic, cellular, neurocircuitry, and behavioral levels. We performed a high-resolution MRI analysis of mutant mice compared with wild-type littermates. Our analysis revealed a striking similarity in the specific volumetric changes of Df(16)A(+/-) mice compared with human 22q11.2 deletion carriers, including in cortico-cerebellar, cortico-striatal and cortico-limbic circuits. In addition, higher resolution magnetic resonance imaging compared with neuroimaging in human subjects allowed the detection of previously unknown subtle local differences. The cerebellar findings in Df(16)A(+/-) mice are particularly instructive as they are localized to specific areas within both the deep cerebellar nuclei and the cerebellar cortex. Our study indicates that the Df(16)A(+/-)mouse model recapitulates most of the hallmark neuroanatomical changes observed in 22q11.2 deletion carriers. Our findings will help guide the design and interpretation of additional complementary studies and thereby advance our understanding of the abnormal brain development underlying the emergence of 22q11.2 deletion-associated psychiatric and cognitive symptoms.

Delayed-onset hypoparathyroidism in an adolescent with chromosome 22Q11 deletion syndrome

OBJECTIVE

To describe the first case of established chromosome 22q11 deletion syndrome with late onset presentation of hypocalcemia secondary to hypoparathyroidism.

METHODS

We present the history, clinical and laboratory investigations, and management of a 17-year-old adolescent boy who presented with 3 separate seizures secondary to hypocalcemia. This patient had an established diagnosis of chromosome 22q11 deletion syndrome at the time of the seizure presentations, but had previously normal calcium levels.

RESULTS

Hypocalcemia was noted during each seizure, with corrected calcium levels ranging from 6.64 to 7.76 mg/dL (reference range, 8.52 to 10.52 mg/dL). The hypocalcemia was secondary to hypoparathyroidism, with parathyroid hormone levels < 2.75 pg/mL (reference range, 22.9 to 68.75 pg/mL). He was treated with calcitriol, 0.5 μg daily, and calcium carbonate, 2,400 mg daily, leading to normalization of serum calcium and resolution of seizures.

CONCLUSION

Chromosome 22q11 deletion syndrome is a relatively common genetic disorder with a wide variety of phenotypic manifestations including cardiac abnormalities, abnormal facies, thymic dysfunction, cleft palate, and hypocalcemia. This case shows that medical practitioners should be aware that hypocalcemia can present after an established diagnosis, which has implications for the management of this disorder.