A case of novel mutation in ANOS1 (KAL1) gene and review of Kallmann syndrome

Summary

Kallmann syndrome (KS) is a genetically heterogeneous condition characterized by hypogonadotropic hypogonadism with coexisting anosmia or hyposmia along with potential other phenotypic abnormalities depending on the specific genetic mutation involved. Several genetic mutations have been described to cause KS. The ANOS1 (KAL1) gene is responsible for 8% of mutations causing KS. A 17-year-old male presented to our clinic with delayed puberty and hyposmia, along with a family history suggestive of hypogonadism in his maternal uncle. Genetic testing for KS revealed complete exon 3 deletion in the ANOS1 gene. To the best of our knowledge, this specific mutation has not been previously described in the literature.

Learning points

Missense and frameshift mutations in the KAL1 or ANOS1 gene located in the X chromosome are responsible for 8% of all known genetic mutations of Kallmann syndrome. Exon 3 deletion is one of the ANOS1 gene is a novel mutation, not reported before. Targeted gene sequencing for hypogonadotropic hypogonadism can be employed based on the phenotypic presentation.

Evidence That the Etiology of Congenital Hypopituitarism Has a Major Genetic Component but Is Infrequently Monogenic

Purpose

Congenital hypopituitarism usually occurs sporadically. In most patients, the etiology remains unknown.

Methods

We studied 13 children with sporadic congenital hypopituitarism. Children with non-endocrine, non-familial idiopathic short stature (NFSS) (n = 19) served as a control group. Exome sequencing was performed in probands and both unaffected parents. A burden testing approach was used to compare the number of candidate variants in the two groups.

Results

First, we assessed the frequency of rare, predicted-pathogenic variants in 42 genes previously reported to be associated with pituitary gland development. The average number of variants per individual was greater in probands with congenital hypopituitarism than those with NFSS (1.1 vs. 0.21, mean variants/proband, P = 0.03). The number of probands with at least 1 variant in a pituitary-associated gene was greater in congenital hypopituitarism than in NFSS (62% vs. 21%, P = 0.03). Second, we assessed the frequency of rare, predicted-pathogenic variants in the exome (to capture undiscovered causes) that were inherited in a fashion that could explain the sporadic occurrence of the proband's condition with a monogenic etiology (de novo mutation, autosomal recessive, or X-linked recessive) with complete penetrance. There were fewer monogenic candidates in the probands with congenital hypopituitarism than those with NFSS (1.3 vs. 2.5 candidate variants/proband, P = 0.024). We did not find any candidate variants (0 of 13 probands) in genes previously reported to explain the phenotype in congenital hypopituitarism, unlike NFSS (8 of 19 probands, P = 0.01).

Conclusion

Our findings provide evidence that the etiology of sporadic congenital hypopituitarism has a major genetic component but may be infrequently monogenic with full penetrance, suggesting a more complex etiology.

Severe hyperthyroidism without symptoms due to nonthyroidal illness in a child with acute hepatitis: case report and literature review

While liver enzyme changes are frequently reported in hyperthyroidism, liver dysfunction itself can lead to alterations in thyroid hormone metabolism. However, the exact relationship between hyperthyroidism and liver dysfunction is unclear. We report an 11-year-old boy presenting with acute hepatitis of unknown etiology, who was incidentally found to have asymptomatic biochemical hyperthyroidism. Despite significant total and free T4 elevation, clinical evidence of thyrotoxicosis was absent. Thyroid I-123 uptake was also reduced. Additional testing revealed slight T3 elevation and significant rT3 elevation. Graves' and Hashimoto's thyroiditis testing was negative. We hypothesize that the biochemical hyperthyroidism was due to transient thyroiditis. Although an etiology for the boy's hepatitis was never determined, and an undiagnosed infectious etiology causing subacute thyroiditis was considered, subsequent testing showing positive thyroid peroxidase antibodies, suggesting autoimmune Hashimoto's thyroiditis as the likely cause of the hyperthyroidism. We believe, furthermore, that the absence of symptoms was the result of concurrent nonthyroidal illness resulting in the biochemical findings of slight T3 elevation and significant rT3 increase despite significant T4 elevation.

SAT-289 Evidence That Combined Pituitary Hormone Deficiency Frequently Has a Digenic/Oligogenic Etiology

Congenital hypopituitarism usually occurs in a child without a family history of pituitary disease. Explanations for such sporadic occurrence include: 1) monogenic inheritance (recessive or de novo), 2) digenic/oligogenic inheritance, and/or 3) nongenetic factors. To help distinguish these possibilities, we studied 9 children with hypopituitarism (HP)(small anterior pituitary gland, ectopic posterior pituitary, and either isolated GH deficiency (n=1) or combined with other pituitary hormone deficiencies(n=8)), with non-consanguineous parents and no family history of pituitary disease. SNP array analyses confirmed paternity and non-consanguinity and excluded significant copy-number variation. Exome sequencing was performed in probands and parents. Candidate variants (coverage >10, confirmed by examining BAM files, population frequency <1%, <2 homozygous subjects in gnomAD, and pathogenic prediction by at least 2 out of 3 prediction algorithms (SIFT, MutationTaster, PolyPhen2)) were identified. Children with non-familial non-endocrine idiopathic short stature (ISS) (n=19, sequenced at the same laboratory followed by simultaneous data processing with HP patients), served as a control group. To assess the frequency of genetic (mono-, di-, or oligogenic) HP cases, we identified heterozygous variants (regardless of inheritance) in 42 genes previously reported to be associated with pituitary development. The average number of variants per proband was greater in HP than in ISS (1.1 vs 0.26, P = 0.04). Similarly, the number of probands with at least 1 variant in a pituitary-associated gene was greater in HP than in ISS (67% vs 21%, P = 0.035). These data suggest that sporadic hypopituitarism is frequently genetic. To assess the number of monogenic cases, we counted the number of candidate variants (in any gene in the genome, to capture undiscovered causes) that were inherited in a fashion that could explain the sporadic occurrence with a monogenic etiology (de novo mutation, autosomal recessive, X-linked recessive). There were fewer monogenic candidates in subjects with HP than ISS (1.6 vs 2.6 candidates/proband, P = 0.03). These data are consistent with approximately 1.6 non-causative variants/proband in both groups plus approximately 1 causative monogenic variant in ISS vs approximately 0 causative monogenic variants in HP. Candidate variants in genes previously reported to explain the phenotype were identified in 0 out of 9 trios with HP and in 8 of 19 trios with ISS (42%). These findings suggest that a monogenic inheritance is less common in HP than in ISS. In conclusion, the findings suggest that sporadic congenital hypopituitarism is frequently genetic but infrequently monogenic, implying a likely digenic/oligogenic etiology.

MON-067 A Perplexing Case of Hyponatremia and Abdominal Pain

Previously healthy 20-year-old female presented with diffuse lower abdominal pain, cramping in nature, multiple episodes of emesis as well as urinary frequency. On day 2 of symptoms, she was treated for a urinary tract infection with antibiotics, as well as NSAIDs and opiates for pain relief. Her serum sodium was 133 mmol/L at this time. On day 3 of symptoms, a CT scan of the abdomen was performed however did not reveal pathology. Her serum sodium was 129 mmol/L at this time. She presented to our ED, on day 5 of symptoms, where serum sodium was down to 122 mmol/L. Despite IV fluids, her sodium continued to decrease to a nadir of 117 mmol/L. Further testing, including a serum osmolality of 242 mOsm/kg, urine osmolality of 540 mOsm/kg, and urine sodium of 207 mmol/L, was consistent with a diagnosis of SIADH. Given persistence of abdominal symptoms along with SIADH further imaging studies, including US abdomen, CT brain and Chest XR, were ordered and returned unremarkable. The constellation of SIADH along with persistent abdominal pain, with negative imaging, lead to consideration of acute intermittent porphyria as a diagnosis. Random urine porphobilinogen was found to be elevated to 147.2 mcmol/L (≤ 2.4) leading to the presumptive diagnosis of acute intermittent porphyria presenting as a neurovisceral attack. Biochemical and genetic testing is being pursued to confirm her diagnosis.

Acute intermittent porphyria is an autosomal dominant hematologic disorder characterized by deficiency in porphobilinogen deaminase, an enzyme in the heme synthesis cascade. Acute attacks are caused by accumulation of porphyrin resulting in autonomic and peripheral neuropathy which can present as abdominal pain, urinary retention, polyneuropathy, dark urine and psychiatric disturbance. Hyponatremia is present in 25–60% of cases which is caused by SIADH or sometimes renal and gastrointestinal sodium loss. Triggers for acute attacks include medications, starvation, infections, hormonal changes and alcohol. Treatment includes avoidance of triggers, IV dextrose and high carbohydrate diet. In severe attacks, IV hemin is used.

Our patient’s urinary tract infection likely triggered her acute symptoms, which was further exacerbated by treatment with NSAIDS and opiates. She developed SIADH which improved with hypertonic saline and fluid restriction.

This case illustrates the need to consider acute intermittent porphyria in the differential diagnosis of SIADH presenting with abdominal pain of unknown etiology.

Diagnosis and management of hypopituitarism

PURPOSE OF REVIEW

This review summarizes pituitary function, and the clinical presentation and treatment of hypopituitarism.

RECENT FINDINGS

Updates in the field include new guidelines and meta-analyses on the diagnosis and treatment of select hormone deficiencies, novel treatment options, and advances in next generation sequencing technology.

SUMMARY

Hypopituitarism is defined as partial or complete loss of a single or multiple pituitary hormones. The clinical presentation of hypopituitarism varies depending on the number and severity of hormone deficiencies. Treatment involves the physiologic replacement of the individual end-organ hormone deficiencies and requires close lifelong monitoring.

Veganism as a cause of iodine deficient hypothyroidism

BACKGROUND

Iodine deficiency is the most common cause of acquired hypothyroidism worldwide. Although uncommon in the Western world, the incidence of iodine deficiency may be rising due to the increased use of restrictive diets.

CASE PRESENTATION

We present a 23-month-old boy diagnosed with iodine deficiency hypothyroidism, induced by a vegan diet.

CONCLUSIONS

This case highlights the risk for iodine deficiency in children on a vegan diet after discontinuation of breast/formula feeding that could lead to acquired hypothyroidism.

Grid-immunoblotting

Grid-immunoblotting is a fast, simple, and efficient method for simultaneously testing multiple allergens utilizing small amount of antibody.

Passive transfer of antibodies to the linear epitope 60 kD Ro 273-289 induces features of Sjögren's syndrome in naive mice

Sjögren's syndrome (SS) is an autoimmune inflammatory disease that primarily affects the lacrimal and salivary glands causing dry eyes and mouth. Antibodies to Ro60 are observed frequently in patients with SS; however, the role of these antibodies in SS initiation and progression remains unclear. The sequence Ro60 273-289 (Ro274) is a known B cell epitope of Ro60 and antibodies to this epitope have been observed in a subset of SS patients and in animals immunized with Ro60 protein. Animals immunized with Ro274 linear peptide develop a Sjögren's-like illness. We hypothesized that passive transfer of anti-Ro274-specific immunoglobulin (Ig)G would induce a Sjögren's-like phenotype. To evaluate this hypothesis, we adoptively transferred affinity-purified Ro274 antibodies into naive BALB/c animals, then evaluated salivary gland histology, function and IgG localization 4 days post-transfer. At this time-point, there was no demonstrable mononuclear cell infiltration and salivary glands were histologically normal, but we observed a functional deficit in stimulated salivary flow of animals receiving Ro274 antibodies compared to animals receiving control IgG. Cellular fractionation and enzyme-linked immunosorbent assay revealed Ro274-specific antibodies in the nucleus and cytoplasmic fractions of isolated parotid salivary gland cells that was confirmed by immunohistochemistry. These data support the hypothesis that antibodies to Ro274 deposit in salivary glands can enter intact salivary gland cells and are involved in the dysregulation of salivary flow in SS.

Grid-immunoblotting

Grid-Immunoblotting is a fast, simple, and efficient method for simultaneously testing multiple allergens utilizing small amount of antibody.

The neuropsychology of cocaine addiction: recent cocaine use masks impairment

Individuals with current cocaine use disorders (CUD) form a heterogeneous group, making sensitive neuropsychological (NP) comparisons with healthy individuals difficult. The current study examined the effects on NP functioning of four factors that commonly vary among CUD: urine status for cocaine (positive vs negative on study day), cigarette smoking, alcohol consumption, and dysphoria. Sixty-four cocaine abusers were matched to healthy comparison subjects on gender and race; the groups also did not differ in measures of general intellectual functioning. All subjects were administered an extensive NP battery measuring attention, executive function, memory, facial and emotion recognition, and motor function. Compared with healthy control subjects, CUD exhibited performance deficits on tasks of attention, executive function, and verbal memory (within one standard deviation of controls). Although CUD with positive urine status, who had higher frequency and more recent cocaine use, reported greater symptoms of dysphoria, these cognitive deficits were most pronounced in the CUD with negative urine status. Cigarette smoking, frequency of alcohol consumption, and dysphoria did not alter these results. The current findings replicate a previously reported statistically significant, but relatively mild NP impairment in CUD as compared with matched healthy control individuals and further suggest that frequent/recent cocaine use [corrected] may mask underlying cognitive (but not mood) disturbances. These results call for development of pharmacological agents targeted to enhance cognition, without negatively impacting mood in individuals addicted to cocaine.