Autosomal recessive polycystic kidney disease (ARPKD) is the recessive form of polycystic kidney disease. It is associated with a group of congenital fibrocystic syndromes. Mutations in the PKHD1 (chromosomal locus 6p12.2) cause ARPKD. Signs and symptoms
Symptoms and signs include abdominal discomfort, polyuria, polydipsia, incidental discovery of hypertension, and abdominal mass. The classic presentation for ARPKD is systemic hypertension with progression to end-stage kidney disease (ESKD) by the age of 15. In a typical presentation, a small number of individuals with ARPKD live to adulthood with some kidney function; but with significant deterioration in liver function. This outcome is postulated to result from expression of the polycystic kidney and hepatic disease gene PKHD1, which is located on chromosome 6p. In severe cases, a fetus will present with oligohydramnios and as a result, may present with Potter sequence. Genetics
The cause of ARPKD is linked to mutations in the PKHD1 gene. PKHD1 gene codes forfibrocystin. Fibrocystin is found in the epithelial cells of both the renal tubule and the bile ducts; deficiency leads to the characteristic polycystic dilation of both structures

ARPKD is a significant hereditary renal disease in that appears in childhood. The prevalence is estimated to be of 1 in 20,000 live births, with a reported carrier frequency of up to 1:70. The single gene mutation called PKHD1 is fully responsible for the disease presentation of ARPKD. This PKHD1 is located on the human chromosome region 6p21.1–6p12.2.
Salpingitis isthmica nodosa (SIN), also known as diverticulosis of the Fallopian tube, is nodular thickening of the narrow part of the  uterine tube, due to inflammation. Signs and symptoms
SIN is associated with infertility and ectopic pregnancy, and may present as either. Pathology
It is characterized by nodular thickening of the tunica muscularis of the narrow (isthmic) portion of the Fallopian tube. In severe cases, it leads to complete obliteration of the tubal lumen. It is uncommonly bilateral.Gross Findings:

One or more nodules 1–2 mm, spanning up to 2 cm
Smooth serosaMicroscopic Findings:

Glandular epithelium within tubal muscularis propria, in continuation with mucosa or (more commonly) discontinuous
Haphazard distribution (akin to adenomyosis) or pseudoinfiltrative
Banal epithelium with tubal differentiation

Diagnosis
Hysterosalpingography, a common technique in the work-up of infertility, is reliable in the diagnosis of SIN, which is seen as small globular collections within the tubal wall, either discontinuous or in continuity with the tubal lumen. Tubal obstruction and hydrosalpinx are commonly seen as well. Other techniques include laparoscopic chromopertubation, salpingoscopy, and transvaginal hydrolaparoscopy (the latter allows visualization of the tubal mucosa)

Treatment
Once suspected clinically and radiologically, patients with infertility and SIN can be managed with segmental resection with tubo-cornual anastomosis, and recanalization if tubal obstruction is detected. Success with gonadotrophin-releasing hormone analogues (GnRH-a) has been documented in terms of remission of nodularity and tubal patency. If fertility preservation is not desired, salpingectomy is recommended. See also
Vasitis nodosa
Salpingitis


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