Treatment for MSS is symptomatic and supportive including physical and occupational therapy, speech therapy, and special education. Cataracts must be removed when vision is impaired, generally in the first decade of life. Hormone replacement therapy is needed if hypogonadism is present.

The recurrence of DOOR in siblings and the finding of DOOR syndrome in a few families with consanguinity suggest that the condition is an autosomal recessive genetic condition. Mutations in TBC1D24 have been identified in 9 families.

In terms of treatment/management for those with Mulibrey nanism should have routine medical follow-ups, additionally the following can be done:

- Growth hormone treatment

- Regular pelvic exams

- Pericardiectomy

Treatments are usually based on the individuals symptoms that are displayed. The seizures are controlled with anticonvulsant medication. For the behavior problems, the doctors proscribe to a few medications and behavioral modification routines that involve therapists and other types of therapy. Even if mental retardation is severe, it does not seem to shorten the lifespan of the patient or to get worse with age.

There are no cures for FHS. Close monitoring of growth in the first few years is essential, as well as annual general health screening and tests listed below. An FHS diagnosis will affect the individual and those there to support them.

Managing symptoms and features of FHS involves maintaining a close watch on the patient's physical as well as mental health. This would include:

- Sequencing of SRCAP exons 31–34 in all suspected cases

- Complete assessments of auditory and visual systems

- Renal and urinary tract ultrasound

- Orthopedic assessment of hip dysplasia and clavicle abnormalities

- Neurologic assessment if there is a suspicion of seizures

- Dental hygiene to prevent cavities and to monitor for malocclusion

- Evaluation for growth hormone deficiency at baseline, to be repeated if loss of growth velocity occurs

- Monitoring of bone age and pubertal timing in case of precocious puberty

- Psychoeducational assessments corrected for deficiencies in expressive language and sensory issues

- Monitoring of behavioral disturbances and provision of early intervention

- Counseling for families regarding recurrence risk and the offspring of individuals with FHS

Special education programs and vocational training to address developmental disabilities are highly recommended, as well as communication rehabilitation with sign language or alternative means of communication. Behavior management strategies could also include referrals to behavior specialists or psychologists for help. For those concerned, genetic counseling can be sought for issues related to testing of at-risk relatives.

Treatment usually involves plastic and reconstructive surgery. Surgery may be needed to correct undescended testes or hernias.

There is currently no cure for GAPO syndrome, but some options are available to reduce the symptoms. Nearsightedness, which affects some sufferers of the disease, can be treated by corrective lenses. Unfortunately, optic atrophy as a result of degradation of the optic nerve (common with GAPO syndrome) cannot be corrected. Corticosteroids have been proposed as a treatment for optic nerve atrophy, but their effectiveness is disputed, and no steroid based treatments are currently available.

Worldwide, it has been documented in 110 persons, 85 of them Finnish. It is a recessive genetic disease. Many people with Mulibrey nanism have parents who are closely related, consanguine. Signs and symptoms are variable, siblings who suffer this disease sometimes do not share the same symptoms.

In a study published in 2012 in the "Journal of Pediatric Endocrinology", a group of scientists reported the long-term effects of a patient diagnosed with FHS undergoing growth hormone therapy from the age of 3.5 years to 9 years old. While the GH seemed to work initially, the patient's growth after the first couple years slowed significantly and the patient reached a stable height far below the target or standard height. The results on GH therapy remain inconclusive.

Recent research mostly centers around the search and confirmation of the gene responsible for FHS. As discussed in the mechanisms section, though the mutation of SRCAP is a widely accepted indicator of a patient diagnosed with FHS, it is not the cause in every case.

Marinesco–Sjögren syndrome (MSS), sometimes spelled Marinescu–Sjögren syndrome, is a rare autosomal recessive disorder.

DOOR (deafness, onychdystrophy, osteodystrophy, and mental retardation) syndrome is a genetic disease which is inherited in an autosomal recessive fashion. DOOR syndrome is characterized by mental retardation, sensorineural deafness, abnormal nails and phalanges of the hands and feet, and variable seizures. A similar deafness-onychodystrophy syndrome is transmitted as an autosomal dominant trait and has no mental retardation. Some authors have proposed that it may be the same as Eronen Syndrome, but since both disorders are extremely rare it is hard to make a determination.

There are no treatment to return to its normal functions. However, there are treatments for the different symptoms.

For the Developmental symptoms, Educational intervention and speech therapy beginning in infancy could help to reduce the high risk for motor, cognitive, speech, and language delay

For theSkeletal features, referral to an orthopedist for consideration of surgical release of contractures. In addition,early referral to physical therapy could help increase joint mobility.

Lastly, Thyroid hormone replacement could help out the thyroid dysfunction

In 2011, it was demonstrated that "de novo" mutations in the gene KAT6B caused YSS.

Hennekam syndrome also known as intestinal lymphagiectasia–lymphedema–mental retardation syndrome, is an autosomal recessive disorder consisting of intestinal lymphangiectasia, facial anomalies, peripheral lymphedema, and mild to moderate levels of growth and intellectual disability.

It is also known as "lymphedema-lymphangiectasia-mental retardation syndrome".

In a subset of patients it is associated with CCBE1 according research published by its namesake, Raoul Hennekam. Other causal mutations were found in the FAT4 gene. Previously, mutations in the FAT4 gene had been only associated with van Maldergem syndrome. The molecular mechanism of the lymphedema phenotype in CCBE1-associated cases was identified as a diminished ability of the mutated CCBE1 to accelerate and focus the activation of the primary lymphangiogenic growth factor VEGF-C.

First reported from Saudi Arabia in 1988, Sanjad-Sakati syndrome, also known as "Hypoparathyroidism-Retardation-Dysmorphism (HRD) syndrome", or less commonly as the "Middle East syndrome", is a very rare genetically inherited disorder seen in the Middle East and children of Middle Eastern origin elsewhere in the world.The condition is named after Sami A. Sanjad and Nadia Awni Sakati.

This disorder is present at birth, however, it may not be understood until several years after birth. Acrodysostosis affects males and females in almost similar numbers. It is difficult to determine the frequency of acrodysostosis in the population as many cases of this disorder cannot be diagnosed properly.

Young–Simpson syndrome (YSS) is a rare congenital disorder with symptoms including hypothyroidism, heart defects, facial dysmorphism, cryptorchidism in males, hypotonia, mental retardation and postnatal growth retardation.

Other symptoms include transient hypothyroidism, macular degeneration and torticollis. The condition was discovered in 1987 and the name arose from the individuals who first reported the syndrome. An individual with

YSS has been identified with having symptoms to a similar syndrome known as Ohdo Blepharophimosis syndrome, showing that it is quite difficult to diagnose the correct condition based on the symptoms present. Some doctors therefore consider these syndromes to be the same.

The mode of inheritance has had mixed findings based on studies undertaken. One study showed that the parents of an individual with YSS are unrelated and phenotypically normal, indicating a sporadic mutation, thus making it difficult to base the cause of the condition on genetic makeup alone. However, another study was done of an individual with YSS who had first cousins as parents, giving the possibility of autosomal recessive inheritance.

There does not yet exist a specific treatment for IP. Treatment can only address the individual symptoms.

Sanjad-Sakati syndrome is a rare autosomal recessive genetic condition seen in offspring of Middle Eastern origin. It was first described in Saudi Arabia, but has been seen in Qatari, Kuwaiti, Omani and other children from the Middle East as well as elsewhere. The condition is caused by mutations or deletions in the TBCE gene of Chromosome No.1.

The condition is characterised by a triad of growth and mental retardation, hypoparathyroidism and dysmorphism.

Some researchers suggest that HGF is transmitted as a Mendelian trait since both autosomal dominant and autosomal recessive transmission has been reported since the early 1970s. (SOURCE 1) In more recent scientific literature, there is evidence in which pedigree analyses confirm autosomal dominant, autosomal recessive or even as X-linked inherited cases of the HGF trait.

In 2002, researchers described the SOS1 gene and proved for the first time that a single-nucleotide–insertion mutation of the SOS1 gene on codon 1083 is the preliminary cause of HGF1 in humans. (Source 1) Later on in 2010, there was a case study done on a 16-year-old male with severe gingival overgrowth, almost covering all teeth. Researchers approached this issue with periodontics - a partial gingivectomy and flap surgery. This case study concluded that surgery followed by regular follow-ups is a good way to treat HGF despite the fact that the risks of re-occurrence of the condition remain high.

Even more recently, a study was done in 2013 on a family that showed history of autosomal recessive inheritance of HGF. The study did not dismiss the return of HGF after treatment but did claim that general surgical intervention after scaling and root planning of teeth supplemented with good oral hygiene is good enough to prevent the re-occurrence of HGF. This case study also acknowledged how HGF can be part of a multi-system syndrome associated with disorders such as Zimmermann Laband syndrome (ear, nose, bone, and nail defects with hepatosplenomegaly), Rutherford syndrome (microphthalmia, mental retardation, athetosis, and hypopigmentation), Murray-Puretic Drescher syndrome and Ramon syndrome.

Treatment is symptomatic, often addressing indicators associated with peripheral pulmonary artery stenosis. Laryngotracheal calcification resulting in dyspnea and forceful breathing can be treated with bronchodilators including the short and long-acting β2-agonists, and various anticholinergics. Prognosis is good, yet life expectancy depends on the severity and extent of diffuse pulmonary and arterial calcification.

This disease has not been shown to be life-threatening or the cause of death in patients. However, treatment is necessary to maintain a healthy lifestyle.

While many cases of HPMRS are caused by mutations in the PIGV gene, there may be genetic heterogeneity in the spectrum of Mabry syndrome as a whole. PIGV is a member of the molecular pathway that synthesizes the glycosylphosphatidylinositol anchor. The loss in PIGV activity results in a reduced anchoring of alkaline phosphatase to the surface membrane and an elevated alkaline phosphatase activity in the serum.

VLDLR-associated cerebellar hypoplasia (VLDLRCH; alternative names: dysequilibrium syndrome, DES; nonprogressive cerebellar disorder with mental retardation) is a rare autosomal recessive condition caused by a disruption of the VLDLR gene. First described as a form of cerebral palsy in the 1970s, it is associated with parental consanguinity and is found in secluded communities, with a number of cases described in Hutterite families.

Because MOMO is such a rare disorder, very few studies have been conducted into its causes. Current research suggests that it is linked to a de novo (new) autosomal dominant mutation.