RESUMO
BACKGROUND: Hypophosphatasia (HPP) is a rare inborn error of metabolism that results from a dysfunctional tissue non-specific alkaline phosphatase enzyme (TNSALP). Although genotype-phenotype correlations have been described in HPP patients, only sparse information is currently available on the genetics of mild type HPP. METHODS: We investigated 5 Japanese patients from 3 families with mild HPP (patients 1 and 2 are siblings; patient 4 is a daughter of patient 5) who were referred to Fujita Health University due to the premature loss of deciduous teeth. Physical and dental examinations, and blood, urine and bone density tests were conducted. Genetic analysis of the ALPL gene was performed in all patients with their informed consent. RESULTS: After a detailed interview and examination, we found characteristic symptoms of HPP in some of the study cases. Mobile teeth or the loss of permanent teeth were observed in 2 patients, and 3 out of 5 patients had a history of asthma. The serum ALP levels of all patients were 30% below the lower limit of the age equivalent normal range. ALPL gene analysis revealed compound heterozygous mutations, including Ile395Val and Leu520Argfs in family 1, Val95Met and Gly491Arg in family 2, and a dominant missense mutation (Gly456Arg) in family 3. The 3D-modeling of human TNSALP revealed three mutations (Val95Met, Ile395Val and Gly456Arg) at the homodimer interface. Severe collisions between the side chains were predicted for the Gly456Arg variant. DISCUSSION: One of the characteristic findings of this present study was a high prevalence of coexisting asthma and a high level serum IgE level. These characteristics may account for the fragility of tracheal tissues and a predisposition to asthma in patients with mild HPP. The genotypes of the five mild HPP patients in our present study series included 1) compound heterozygous for severe and hypomorphic mutations, and 2) dominant-negative mutations. All of these mutations were at the homodimer interface, but only the dominant-negative mutation was predicted to cause a severe collision effect between the side chains. This may account for varying mechanisms leading to different effects on TNSALP function.
RESUMO
AIMS: Previous studies have reported that the incidence of obstructive sleep apnea syndrome (OSAS) in patients with depression is higher than in the general population. We examined the risk factors to predict OSAS in mood disorder patients with depressive symptoms. METHOD: We conducted polysomnography for patients who satisfied the following criteria: (i) diagnosis of major depressive disorder or bipolar disorder according to the Mini-International Neuropsychiatric Interview (MINI); (ii) a score of > or =10 on the Hamilton Rating Scale for Depression (HAM-D); (iii) fulfillment of either (a) or (b) below: (a) at least one of the following: severe snoring, witnessed apnea during sleep, excessive daytime sleepiness; (b) at least one of the following plus an oxygen desaturation index of 4% > or =5 times/h by pulse oximeter: mild snoring, sleep disturbance, headache, high blood pressure. The patients with apnea hypopnea index > or =5 were diagnosed with OSAS. RESULTS: Of the 32 mood disorder patients who met the subject conditions, 59.4% had OSAS. The diagnosis rate with our criteria was significantly higher than the previously reported incidence of OSAS in patients with depression. There was no significant difference among diagnosis rates as to individual risk factors or the number of risk factors. A multiple regression test showed no significant association between apnea-hypopnea index and other clinical factors including depression severity. CONCLUSION: The present results showed that OSAS can be detected at a remarkably higher rate by considering appropriate OSAS risk factors in mood disorder patients, and suggested that there is a high rate of undetected and therefore untreated OSAS among mood disorder patients.
