Lower urinary tract symptoms and prostatic calculi: A rare presentation of alkaptonuria

The influence of prostatic calculi on lower urinary tract symptoms and sexual dysfunction: a narrative review

Prostatic calculi (PC) are commonly found in patients who present for urologic consultation. However, the effect of PC on urinary symptoms remains controversial. In this study, we searched the Embase and PubMed databases for literature related to the following keywords: “prostatic calculi”, “prostatic stone”, “prostatic lithiasis” and “prostatic calcification”, along with the limits, “lower urinary tract symptoms”, “sexual dysfunction”, “erectile dysfunction”, “erectile function”, and “premature ejaculation”. According to the literature, there are various subtypes of PC based on X-ray or ultrasound findings, including type I/II, type A/B, and endogenous PC/extrinsic PC. Furthermore, the formation of PC remains unclear, and more importantly, the ability of PC to cause lower urinary tract symptoms (LUTS) and sexual dysfunction (SD) is worth exploring. We retrospectively reviewed all available literature and found that most studies agreed that PC are associated with LUTS. The factors which may play an important role in the pathogenesis of LUTS include the size and location of PC, induced inflammation, and the blood flow of the prostate. Similarly, SD was also examined in the patients with PC, and psychological factors cannot be ignored in this regard. However, more in-depth study of the molecular mechanisms, including prospective, controlled, longitudinal, and large- sample studies, are needed in the future.

Founder effects of the homogentisate 1,2-dioxygenase (HGD) gene in a gypsy population and mutation spectrum in the gene among alkaptonuria patients from India

INTRODUCTION

Alkaptonuria (AKU) is a rare metabolic disease. The global incidence is 1:100,000 to 1:250,000. However, identification of a founder mutation in a gypsy population from India prompted us to study the prevalence of AKU in this population and to do molecular typing in referred cases of AKU from the rest of India.

OBJECTIVE

To determine the prevalence of AKU in the gypsy population predominantly residing in the seven districts of Tamil Nadu. To determine the molecular characteristic of AKU cases referred to our clinic from various parts of India.

METHOD

Urine spot test to detect homogentisic acid followed by quantitative estimation using high-performance liquid chromatography in 499 participants from the gypsy population and confirming the founder mutation in those with high levels by sequencing. Sequence the homogentisate 1,2-dioxygenase (HGD) gene to identify mutations and variants in 29 AKU non-gypsy cases.

RESULTS

The founder mutation was detected in homozygous state in 41/499 AKU-affected individuals of the gypsy community giving a high prevalence of 8.4%. Low back pain, knee pain, and eye and ear pigmentation were the most common symptoms and signs respectively. The commonest mutation identified in the non-gypsy AKU cases was p.Ala122Val.

CONCLUSION

High prevalence of AKU in the inbred gypsy population at 8.4% was detected confirming the founder effect. Urine screening provided a cost-effective method to detect the disease early. Mutation spectrum is varied in the rest of the Indian population. This study identified maximum number of mutations in exon 6 of the HGD gene. Key Points • High prevalence (8.4%) of alkaptonuria (AKU) in the gypsy population due to founder mutation in the HGD gene. • Inbreeding exemplifies the founder effects of this rare genetic disorder. • Urinary screening is a cost-effective method in this community for early detection of AKU and intervention. • The mutation spectrum causing AKU is diverse in the rest of the Indian population.

Prostatic Calculi: Do They Matter?

INTRODUCTION

Prostatic calculi (PC) are frequently detected at computed tomography or ultrasound in men attending the health center or the urology outpatient department. PC have attracted more attention from urologists, but the clinical significance of PC is unknown.

AIM

To review the available literature on the effects of PC on prostatic diseases and sexual function in men.

METHODS

Relevant clinical trials were identified by searching the PubMed, Embase, and Cochrane Library databases. Results were classified, summarized, and analyzed.

MAIN OUTCOME MEASURES

Transabdominal and rectal ultrasonography; urodynamics analysis; International Prostate Symptom Score; pathologic examination of prostatic tissue; prostate-specific antigen; and expressed prostatic secretion.

RESULTS

PC can not only prolong the duration of bothersome symptoms but also decrease the cure rate of antibacterial therapy in patients with chronic prostatitis. Patients with PC usually have more severe lower urinary tract symptoms (LUTS), and some studies reported that moderate to marked PC are a predisposing factor for moderate to severe LUTS. Studies also reported that the serum level prostate-specific antigen is not influenced by PC. In addition, the presence of PC is not associated with an increased risk of prostate cancer. However, the correlation between PC in the peripheral zone and prostate cancer is statistically significant. In addition, the association between PC and Gleason scores is controversial. Some novel studies suggested that PC might play an important role in sexual impairment in middle-age men or men with chronic pelvic pain syndrome or chronic prostatitis. Recently, PC were found to increase the incidence of severe LUTS, urinary retention, and hematospermia after transrectal ultrasound-guided prostate biopsy.

CONCLUSION

PC can aggravate LUTS, chronic prostatitis, and sexual dysfunction in men, but the association between PC and prostate cancer is still controversial. Cao J-J, Huang W, Wu H-S, et al. Prostatic Calculi: Do They Matter? Sex Med Rev 2018;6:482-491.

Extensive prostatic calculi in alkaptonuria: An unusual manifestation of rare disease

Extensive prostatic calculi in a young man should always elicit the suspicion of alkaptonuria. Although prostatic calculi are seen in chronic prostatitis, chronic pelvic pain syndrome and benign prostate hyperplasia, none of these have prostatic calculi or calcification as extensive as in alkaptonuria. A 36 years young man who had severed obstructive lower urinary tract symptoms with extensive prostatic calculi was found to be alkaptonuric on further evaluation.

Mutation screening of the HGD gene identifies a novel alkaptonuria mutation with significant founder effect and high prevalence

Alkaptonuria (AKU) is an autosomal recessive disorder; caused by the mutations in the homogentisate 1, 2-dioxygenase (HGD) gene located on Chromosome 3q13.33. AKU is a rare disorder with an incidence of 1: 250,000 to 1: 1,000,000, but Slovakia and the Dominican Republic have a relatively higher incidence of 1: 19,000. Our study focused on studying the frequency of AKU and identification of HGD gene mutations in nomads. HGD gene sequencing was used to identify the mutations in alkaptonurics. For the past four years, from subjects suspected to be clinically affected, we found 16 positive cases among a randomly selected cohort of 41 Indian nomads (Narikuravar) settled in the specific area of Tamil Nadu, India. HGD gene mutation analysis showed that 11 of these patients carry the same homozygous splicing mutation c.87 + 1G > A; in five cases, this mutation was found to be heterozygous, while the second AKU-causing mutation was not identified in these patients. This result indicates that the founder effect and high degree of consanguineous marriages have contributed to AKU among nomads. Eleven positive samples were homozygous for a novel mutation c.87 + 1G > A, that abolishes an intron 2 donor splice site and most likely causes skipping of exon 2. The prevalence of AKU observed earlier seems to be highly increased in people of nomadic origin.